The Pennsylvania State University

The Graduate School

Department of Energy and Mineral Engineering

EFFECTS OF SAMPLE HOLDERS ON ACTIVATED CARBON SORBENT

TUBES WHEN MEASURING ORGANIC VAPOR CONCENTRATIONS

A Thesis in

Energy and Mineral Engineering

by

Brian S. Marpoe

2010 Brian S. Marpoe

Submitted in Partial Fulfillment

of the Requirements

for the Degree of

Master of Science

August 2010

ii

The thesis of Brian Marpoe was reviewed and approved* by the following:

William A. Groves

Associate Professor of Industrial Health and Safety

Thesis Advisor

R. Larry Grayson

Professor of Energy and Mineral Engineering

Mark S. Klima

Associate Professor of Mineral Processing and Geo-Environmental Engineering

Yaw D. Yeboah

Professor and Department Head of Energy and Mineral Engineering

*Signatures are on file in the Graduate School

iii

ABSTRACT

A study was conducted to examine whether there are significant differences

between organic vapor concentrations measured using activated carbon sorbent tubes

with three different sample holder configurations: no sample holder (open tube), and

using SKC- and Buck-brand sample holders. A two-level fractional factorial

experimental design was used with the following factors and levels: Vapor (low boiling

point, high boiling point), Pump Type (pulsating, continuous), Exposure Profile (variable,

constant), Flow Rate (30 mL/min, 200 mL/min), Duration (30 min, 80 min), and Sample

Placement (mannequin, free-hanging). Two of each sample holder configuration (six

total) were placed in an exposure chamber and a dynamic test-atmosphere generation

system was used to prepare atmospheres containing approximately 12 to 15 ppm n-

hexane (low b.p. vapor: 69º C) or m-xylene (high b.p. vapor: 139 ºC) with exposure

profiles and sampling conducted according to the run sheet generated from the

experimental design. A total of 24 runs were completed with six samples collected per

run, yielding 144 samples which were analyzed by GC/FID.

Concentration results for each pair of SKC- and Buck-brand sample holders were

averaged and normalized by dividing by the average result for the open-tube sampler

from the same run to eliminate the effect of daily variation in chamber concentrations.

The resulting ratio of sample tube holder and open tube concentrations was used as the

response variable. Results of ANOVA using the General Linear Model (MINITAB

Release 14) identified Flow Rate (p=0.006) and Sample Holder (p=0.021) as significant

iv

factors. However, the magnitude of the effect was small with the mean concentration

ratio ranging from 0.99 -1.04 for the Flow Rate effect, and from 0.99-1.03 for the Sample

Holder effect. These results suggest that exposure assessment errors resulting from use

of sorbent tube sample holders for organic vapor monitoring are relatively small and not

likely to be of practical importance.

v

TABLE OF CONTENTS

List of Figures................................................................................................................vii

List of Tables................................................................................................................. .ix

Acknowledgements..........................................................................................................x

Chapter 1 Introduction ................................................................................................. ...1

Chapter 2 Background ................................................................................................. ...4

2.1 Review of Literature ...................................................................................... ...4

2.1.1 History of Industrial Hygiene .............................................................. ...4

2.1.2 Personal Sampling Methods and Techniques ...................................... ...7

2.1.3 Solid Sorbent Gas and Vapor Samplers .............................................. .12

2.1.4 Error Associated With Sampling ......................................................... .17

2.2 Overall Benefits of the Study ........................................................................ .19

2.3 Specific Aims ................................................................................................. .20

Chapter 3 Methods ....................................................................................................... .21

3.1 Preliminary Test Atmosphere Generation Tests ............................................ .21

3.2 Equipment and Instrumentation ..................................................................... .23

3.2.1 SKC and Buck Sample Holders .......................................................... .23

3.2.2 Continuous and Pulsating Pumps ........................................................ .25

3.2.3 Photo Ionization Detector (PID) .......................................................... .27

3.2.4 Exposure Chamber and Gas Generation System ................................. .28

vi

3.3 Experimental Design ..................................................................................... .30

3.4 Experimental Procedure ................................................................................. .33

Chapter 4 Results and Discussion ................................................................................ .36

4.1 Individual Factor Results Using Measured Concentrations .......................... .36

4.2 Individual Factor Results Using a Ratio of Measured Concentrations.......... .44

4.3 Overall Sample Holder Results ..................................................................... .48

4.4 Comparing Sampled Concentration vs. Measured PID Concentration ......... .50

Chapter 5 Conclusions ................................................................................................. .53

References .................................................................................................................... .54

Appendix A Raw Data ................................................................................................ .56

vii

LIST OF FIGURES

Figure 1.1: SKC Sample Holder....................................................................................2

Figure 2.1: NIOSH Design of Charcoal Tube (Crisp, 1980) ....................................... 15

Figure 2.2: A.P. Buck Sample holder (left), open tube sample (center), and SKC

Sample Holder (right) ................................................................................... 16

Figure 3.1: SKC Sample Holder .................................................................................. 24

Figure 3.2: Adjustable Buck Sample Holder ............................................................... 25

Figure 3.3: Pulsating Pump (left), DryCal, and Continuous Pump (right) .................. 26

Figure 3.4: MiniRAE 2000 PID ................................................................................... 27

Figure 3.5: Water Bath With Gas Washing Bottle ...................................................... 29

Figure 3.6: Test Atmosphere Generation System ........................................................ 29

Figure 3.7: Actual Chamber Used in the Study ........................................................... 30

Figure 3.8: Mannequin and Free Hanging Stand ......................................................... 34

Figure 3.9: Constant Concentration Exposure Profile for Vapors ............................... 34

Figure 3.10: Variable Concentration Exposure Profile for Vapors ............................. 35

Figure 4.1: ANOVA Results for Concentration (PPM) as a Response Variable......... 38

viii

Figure 4.2: Interaction Plot for Vapor, Pump Type, and Duration Factors ................. 39

Figure 4.3: Measured PID Concentration for Run 4L In Experimental Design. ......... 40

Figure 4.4: Concentration Rise of Both Vapors in the Experimental Chamber...........42

Figure 4.5: Rate of Decrease in Vapor Concentration ................................................. 43

Figure 4.6: ANOVA Results for Ratio of Concentrations as a Response Variable ..... 45

Figure 4.7: Interaction Plot for Flow Rate and Sample Holder ................................... 47

Figure 4.8: Interval Plot Comparing Means of Measured Concentration and PID

Concentration.............................................................................................51

ix

LIST OF TABLES

Table 2.1: The Use of Solid Sorbents in Air Sampling from 1960-1980 ................... 14

Table 2.2: Required Accuracy For Specific Concentration Levels ............................. 18

Table 3.1: Chemical Properties and Exposure Limits for n-Hexane and m-Xylene ... 22

Table 3.2: Parameters For Test Atmosphere Generation ............................................. 23

Table 3.3: Effects Examined in Multi-Factorial Design .............................................. 31

Table 3.4: Study Design Matrix ................................................................................... 32

Table 4.1: Analysis of Variance Results for Concentration......................................... 37

Table 4.2: Analysis of Variance for Concentration with Interaction Terms ................ 379

Table 4.3: Analysis of Variance Results for Ratio of Concentrations ......................... 40

Table 4.4: Analysis of Variance Results for Ratio of Concentrations with

Interaction Terms ........................................................................................ 456

Table 4.5: Ratio's of Open Holder and Sample Holders..............................................469

Table 4.6: T-test Comparing Measured Concentration vs. PID Concentration...........50

Table 4.7: One-Sample T-test Comparing Ratio's of Measured and PID

Concentrations.............................................................................................51

x

ACKNOWLEDGEMENTS

I would like to express my sincere gratitude and thanks to my advisor Dr. William

Groves whose advice, encouragement, and support throughout my stay here at Penn State

from the initial to final level helped me to develop an understanding of the subject.

Support for this project by the National Institute for Occupational Safety and

Health (NIOSH) is gratefully acknowledged.

Lastly, I would like to thank my parents, Harold and Deb, for helping to support

me financially and emotionally, not only through my collegiate career, but throughout my

life.

1

Chapter 1

Introduction

When air sampling is needed to test for organic gases or vapors in a work place

the most common type of sampling uses a sampling train that consists of a pump and

carbon sorbent tube. The sorbent tube is filled with activated carbon where vapors can be

adsorbed. The sample can then be desorbed from the carbon using carbon disulfide (CS2)

into a solution and analyzed using gas chromatography. Gas chromatography coupled

with a Flame Ionization Detector (FID) is used to evaluate the solution so the sample

concentration can be calculated. When opening the glass sorbent tube before sampling,

the tips have to be broken off each end, leaving behind sharp glass edges. These glass

edges could easily harm a worker during personal sampling if they are not careful.

Sample holders have been designed to protect workers from the glass edges of carbon

sorbent tubes by placing the sample holder directly over the sorbent tube and still

allowing it to sample with no hindrances. There are different brands and types of sample

holders, but all are very similar. They usually are a plastic casing that screws directly

over the sample tube, and has a clip that allows it to be placed on a worker’s collar or

shirt as seen in Figure 1.1.

2

Figure 1.1: SKC Sample Holder

A previous study was done that involved sampling vapors in a chamber while a

subject was performing a physical test to evaluate a physiologic sampling pump (PSP)

(Lin et al., 2008; Lee et al., 2009; Lin et al., 2010) . From this study, the air samples

were taken using a sample holder or using an open sorbent tube. Although the purpose of

the experiment was to examine the performance of the PSP and its custom-designed

sample holder, results were also obtained using a traditional sampling pump with and

without a sample holder. These results suggested possible variations and a significant

difference, on the order of 10%, between sampled vapor concentrations with and without

a sample holder. This proposed the question, "Are sample holders affecting sampled

concentrations?" To address this problem, the National Institute for Occupational Safety

and Health (NIOSH) funded this research project to determine if sample holders were

affecting the measured concentrations, and if any underlying factors played a role in the

different concentrations.

3

The project focused on experimentally examining whether using three different

sample holder configurations would cause significant differences (>10%) between

concentrations measured using carbon sorbent tubes for organic vapors. The three types

of sample holder configurations were: a) no sample holder, b) using a SKC brand sample

holder, c) using an A.P. Buck brand sample holder. The project also aimed to identify

and characterize significant factors affecting concentrations such as the chemical and

physical properties of vapors, type of sampling pump, exposure profile, sampling flow

rate, and if the sample holder was placed on a mannequin or placed on a free-hanging

sampling stand. Lastly, if significant effects were identified, evaluating mechanisms that

governs the effects would be analyzed.

A fractional factorial experimental design was used to incorporate all of these

factors into 24 experiments. These experiments involved sampling organic vapors in a

chamber using sampling trains under the conditions given in the experimental design. A

vapor generation system put a known concentration of the vapor through the chamber,

while six samples were taken using different sample holders (two of each type) to

determine the differences in each measured concentration. From the previous study it

was hypothesized that sample holders were causing differences in measured

concentrations.

4

Chapter 2

Background

A review of the literature relevant to the history and background of this project is

presented in this chapter. An overview of the experiment done before this project that

helped in development of the experimental design is also described. Lastly, the overall

objectives and specific aims for this study will be discussed.

2.1 Review of Literature

This section presents a review of current literature on the history of gas and vapor

sampling, measuring with carbon sorbent tubes, and associated error while sampling. It

should be noted that not much research has occurred with sample holder designs and

uses.

2.1.1 History of Industrial Hygiene

Hippocrates recognized and recorded the very earliest signs of occupational

disease during the 4th century B.C by discovering the existence of lead toxicity in the

mining industry. Ulrich Ellenbog published a pamphlet on occupational diseases in 1473,

and Bernadino Ramazzini wrote the first full treatise on the same subject in 1700 (Cullis

and Firth, 1981), but very little concern was put forth to protect the health of workers

until the 19th century. It was not until 1833 that the Factory Acts of Great Britain were

passed because of the rapid increase of industrial diseases and accidents happening in

5

Great Britain. These acts were aimed more toward providing the workers with

compensation for accidents rather than preventing and controlling the causes, but are

considered the first effective legislative acts in industry that required concern for the

workers (Leidel, Busch, and Lynch, 1977).

In 1908, the United States passed a compensation act (Federal Employers'

Liability Act; FELA) for injured employees of any interstate railroad, and in 1911 the

initial state worker's compensation laws were agreed upon by the government. Since

worker's compensation is administered on a state-by-state basis, individual states slowly

created their own worker's compensation laws, and by 1948 every state had some form of

worker's compensation to take care of injured employees. Employers started to become

more aware of health and safety incident rates over the next 20 years. The increase of

awareness with the ever-growing industrial type jobs led to the passing of multiple health

and safety acts in the 1960's. The largest movement made for the health and protection of

workers and prevention of diseases came from The Federal Coal Mine Health and Safety

Act of 1969 (Leidel, Busch, and Lynch, 1977). This act helped develop and set the basis

of what United States hygienists believe is the most important piece of federal legislation:

The Occupational Safety and Health Act of 1970 (Perkins, 1997).

Prior to 1970, very few states were regulating health and safety in the workplace.

Injury, accident, and death statistics were available, and people started to realize the

losses from every day work places. In 1968, the Secretary of Labor William Wirtz stated

that there will be 55 dead, 8,500 disabled, and 27,200 hurt every day in America's work

places (Mintz, 2002). The Occupational Safety and Health Act was developed in 1970 to

help govern the health and safety of workers in the private sector and federal government

6

in the United States. The Act's main goal was to keep the workplace safe by keeping it

free from any recognized hazards, such as excessive noise levels, unsanitary conditions,

toxic chemicals, and mechanical dangers. Taken directly from the purpose in the

preamble to the Act it states:

"To assure safe and healthful working conditions for working men and

women; by authorizing enforcement of the standards developed under

the Act; by assisting and encouraging the states in their efforts to assure

safe and healthful working conditions; by providing for research,

information, education, and training in the field of occupational safety

and health; and for other purposes." (Occupational Safety and Health

Act of 1970)

This act created a new administrative unit in the Department of Labor, the Occupational

Safety and Health Administration (OSHA). OSHA was to serve and regulate the work

places throughout the United States and ensure the safety of all employees. OSHA also

served to create the standards, rules, and regulations that every industry and work place

would have to comply with. The OSHA standards that became important to industrial

hygienists were the Permissible Exposure Limits (PEL) designed to control chemical

substance concentrations to keep workers safe (Perkins, 1997). In 1974, along with the

National Institute for Occupational Safety and Health (NIOSH), OSHA began putting

together tables of approximately 400 chemical substances. Health standards for each

chemical substance were created and included areas such as:

Measurement of employee exposure

Medical surveillance

7

Methods of compliance

Handling and use of liquid substances

Employee training

Recordkeeping

Sanitation and housekeeping (Leidel, Busch, and Lynch, 1977)

These standards could be followed using appropriate sampling and analytical methods for

measuring employee exposures that would be later developed by OSHA.

2.1.2 Personal Sampling Methods and Techniques

Personal sampling is the best way to monitor what and how much of a

contaminant an employee is being exposed to. Industrial hygiene programs' have one

main goal, and it is to accurately evaluate employees' occupational exposures to airborne

contaminants using sampling techniques (Leidel, Busch, and Lynch, 1977). OSHA has

developed many guidelines and rules to sample workers and work places for harmful

aerosols, gases, vapors, or dusts. Even though there are guidelines for sampling, there is

no generally accepted standardized procedure for air quality testing. Employers base

their monitoring responsibilities on several factors:

1) Industries will put forth different efforts and approaches to air monitoring

depending on the type of work done. A chemical company that deals with

toxic chemicals daily will put more effort into an air monitoring program

than a plant putting together automobile parts.

8

2) The safety manager or health professional in the company will have

different views on responsibility from company to company.

3) Air quality monitoring requires manpower, capital equipment,

laboratories, and a reasonably high level of expertise that a company will

have to afford. (Cullis and Firth, 1981)

In 1974, NIOSH and OSHA put together a book of guidelines for air sampling in

response for the need of standardized methods. One of the important requirements for

each air sampling method under consideration was to provide results on average within

±25% of the (true) concentration 95% of the time (Kennedy, Fischbach, Song, Eller, and

Shulman, 1996). These types of confidence intervals take into account many areas of

error with sampling and will be discussed later in the chapter.

Industrial hygiene analytical methods are directed towards personal sampling of a

worker. To prepare a method for personal sampling it is best to ask oneself the following

six questions: what, where, how long, when, who, and how many to sample? When

answering the question what to sample for, the response should be anything that may

cause harm or sickness to a worker or the surrounding environment in the workplace.

Where to sample is a difficult question that is important with this study which is

examining the use of sample holders. Studies have shown that there is bias whether or

not the sample is taken from the dominant or non-dominant side of the worker, and

similar studies have shown opposite results. Either way, hygienists still attach the

sampler on a worker's shirt or collar in the breathing zone, and if multiple samples are

needed it is suggested to alternate sides to eliminate any bias. The breathing zone is

defined by Perkins to be anywhere around the nose or mouth. How long to sample

9

should be based on what is being sampled. Does the hazard produce acute or chronic

effects? A time weighted average (TWA) over eight hours is the common answer, which

can then be compared to the occupational exposure limit (OEL). When to sample is

another difficult question. Hygienists are most likely to pick the worst-case sampling

time to determine if workers are being overexposed to the hazard and it is usually what is

done to ensure the safety of the worker. NIOSH developed a technique in 1977 called the

Recommended Employee Exposure Determination and Measurement Strategy, which

helped indentify who to sample in the work place (Perkins, 1997). The strategy

suggested choosing the worst-case exposure situation and sampling that worker. This

was to ensure that if the sample results come back in compliance there would be no need

for further sampling. Lastly, how many samples should be taken has had lengthy

considerations. Initially, large sample sizes were recommended to ensure enough

employees were being sampled, but today hygienists must consider adequate statistical

design of their sampling strategy to determine the number of samples needed (Perkins,

1997). All of these questions need to be answered to produce a good monitoring

program.

When developing a monitoring program, it is first helpful to understand the

reasons for sampling for air contaminants and how the resulting data will be used.

Reasons for air monitoring is given by Cullis (Cullis and Firth, 1981), and they are as

follows:

1) To protect the worker from sickness, impaired health, discomfort, and

inefficiency due to working conditions;

10

2) To fulfill the company's responsibilities under the local Health and

Safety legislation;

3) To ensure compliance with air quality standards;

4) To establish an ongoing record of employee exposure levels;

5) To indicate areas and operations where respiratory protection may be

necessary; and

6) To provide data for epidemiological surveys, where medical records are

analyzed with exposure data.

Cullis states that the main goal of an air monitoring program is to evaluate the average

exposure and range of exposures for every job situation in the company. Sample results

that are exceeding the recommended OEL's are a guide for safety professionals to

develop a plan to improve the conditions. Whether it means re-designing the work

practices, using a new type of engineering control, or the addition of personal protective

equipment (PPE); monitoring programs help to minimize worker's exposure (Cullis and

Firth, 1981). There are different personal monitoring techniques that can be used to

identify airborne contaminants.

There are diverse types of devices used to sample organic gases and vapors in a

work place. These types of instruments include dosimeters, chemical stain devices, and

time weighted average (TWA) sampling devices. This study focused on TWA sampling

devices for gases and vapors. TWA instruments sample for a known sampling time with

a known flow rate. Once the amount of contaminant sampled for is determined by

analysis, an average concentration can be determined by knowing the mass of the

contaminant and the amount of volume that passed through the TWA device. Different

11

types of TWA samplers include slow-filling containers, evacuated metal containers,

impingers, bubblers, and vapor adsorption tubes (Cullis and Firth, 1981).

It is less difficult to sample for gases and vapors rather than aerosols in an

occupational environment because at standard temperatures and pressures they follow the

ideal gas law and mix freely with air. This allows the gas or vapor to reach equilibrium

fairly quickly. Since gases and vapors are often used together, it should be noted there

are differences between the two. Gases are substances that at standard conditions (70°F

and 1 atm) are in their normal physical state. Vapors are gaseous forms of a substance

that under standard conditions may exist as a solid or liquid. Both gases and vapors are

collected with the same air sampling device and methods. The two techniques used to

sample for gases and vapors require laboratory analysis of collected samples, or use a

direct-reading instrument that is capable of sampling a volume of air (Peach and Carr,

1986). The two techniques are very different, and both have their pros and cons. A

direct-reading instrument can get immediate concentrations; while sampling using a

charcoal tube requires time between measurements and obtaining the results. However,

there are very few gases and vapors that OSHA allows Photo Ionization Detectors (PID's)

to be used for compliance measurements, so traditional laboratory analysis is most often

used to test a worker's safety. Both techniques are used in this study, but the main focus

is the method used that needs laboratory analysis, and more specifically solid sorbent gas

samplers.

12

2.1.3 Solid Sorbent Gas and Vapor Samplers

Gas and vapor adsorption tubes are the most widely used, and probably the most

convenient method for collecting TWA samples. Before 1936, filtration techniques were

being used to measure aerosols such as asbestos, coal dust, and silica in industrial

atmospheres, but gases and vapors also were causing diseases among workers. The

adsorption properties of activated carbon, silica gel, and alumina were documented in the

mid-1930's. Early attempts tried using gravimetric techniques to analyze these samples

but were unsuccessful due to water vapor and other contaminants also being adsorbed.

Initially, scientists could not determine ways to separate the gas or vapor from other

materials on the sample. This in turn led to additional weight on the samples, so the mass

could not be determined of the contaminant, which hindered calculating the TWA

concentrations. In 1952, a separation technique, gas chromatography (GC), became

available and by 1958, experiments were being done in conjunction with charcoal

sorbents and gas chromatography analysis (Perkins, 1997). The development of the small

battery-operated pump around 1960 helped push the use of charcoal to sample for gases

and vapors on a worker. The pump allowed for samples to be taken in the worker's

breathing zone and over an entire work shift (Rappaport and Kupper, 2008). Finally in

1964, carbon disulfide (CS2) was discovered to remove contaminants from the charcoal,

and not interfere with the analysis of other compounds in the GC column. Industrial

Hygienists could then unload a charcoal tube into a vial, and add a known amount of CS2

to prepare an injection sample for GC analysis. After this discovery was made, charcoal

became the solid sorbent of choice for sampling gases and vapors (Perkins, 1997).

13

The principle of adsorption is to pull a known volume of air at a constant flow

rate over the charcoal in a glass tube. As the air passes through the tube, the molecules of

gas can be adsorbed onto the charcoal while being chemically unchanged. The chemical

can then be desorbed using a liquid solvent and analyzed (Peach and Carr, 1986). To act

as an effective collecting medium a sorption material must fulfill several requirements:

1) It must be able to trap small concentrations of contaminant from a stream

of air, and retain it until an analysis can be made;

2) A convenient efficient method of desorption must be available;

3) The capacity of the sorbent within the sampler tube must be large enough

to retain an amount of contaminant sufficient to facilitate its analysis;

4) The sorbent must be such that no chemical change occurs to the

contaminant while stored; and

5) The sorbent should adsorb the contaminant in the presence of other

contaminants (Crisp, 1980).

Solid sorbents other than charcoal can be used to adsorb vapors and gases. Some

examples of such sorbents are porous polymers, gas-liquid chromatography

compositions, silica gel, clathrate silicates, and alumina (Crisp, 1980). These other

materials were introduced because activated carbon cannot adsorb some materials when

another sorbent can. For example, carbon does not bind well with alcohols or other polar

compounds in which case another sorbent would be used. Active charcoal and carbon are

the primary ones used as sorbents, but other applicable sorbents are listed in Table 2.1.

14

Table 2.1: The Use of Solid Sorbents in Air Sampling from 1960-1980 (Crisp, 1980)

Type of Sorbent Number of Compounds

Reported Adsorbed

Active Charcoal and Carbon 139

Porous Polymers 131

Silica Gel 84

Loaded Chromatographic Columns 43

Molecular Sieves 6

Alumina 6

Miscellaneous 3

The charcoal can be obtained from a variety of materials ranging from coconut

shells, coal, wood, peat, cotton, and Douglas fir (Levin and Carleborg, 1987). The main

advantage of using charcoal is that it has an extensive internal surface area. This area can

be as large as 10,000 sq. ft. per gram of material, which greatly enhances its adsorption

capacity (Peach and Carr, 1986). For industrial work, two types of charcoal have been

used most often. Coconut charcoal is the sorbent recommended by NIOSH and is

utilized the most, but charcoal made from petroleum is used the second highest (Perkins,

1997).

The first standardized miniature adsorbent tube was developed by NIOSH and the

design can be seen in Figure 2.1 (Anderson, Levin, Lindahl, and Nilsson, 1984).

15

Figure 2.1: NIOSH Design of Charcoal Tube (Crisp, 1980)

NIOSH produced the charcoal tube to be made from glass 7-cm long, 4-mm i.d., and 5-

mm o.d., and made it so that both ends are sealed until sampling begins. There are two

sections of charcoal in the tube. The primary section contains 100 mg, and the second

section is 50 mg of charcoal. Each section is analyzed separately and the back section is

used to indicate breakthrough. To open the tube for sampling, each tip is broken off and

attached accordingly to a sampling pump with a rubber hose. Sample holders are placed

over the tube for two reasons. The first reason is ensure worker safety from the sharp

glass edges on the end. The second reason is the sample holder allows the charcoal tube

to be easily attached to the worker with a clip directly in the breathing zone, yet not

interfering with basic job tasks. After sampling, the charcoal tube should be sealed

effectively with plastic caps that come with the tubes, and then stored according to the

volatility and reactivity of the contaminant sampled until analysis can be done (Perkins,

1997).

Figure 2.2 shows two types of sample holders and an open tube. From the image

it is easy to see that sample holders are very similar. Other types of sample holders are

also available, but all operate the same way. Depending on the manufacturer of the

16

sample holder, a needle valve may be included on the sample holder to adjust the flow

rate, which also can be seen in Figure 2.2 on the open tube in the middle.

Figure 2.2: A.P. Buck Sample Holder (left), Open Tube Sample (center), and SKC

Sample Holder (right)

The analysis of solvent gas and vapors is typically done using gas

chromatography. Once the contaminant has been adsorbed onto charcoal, it can be

desorbed using a suitable solvent and analyzed using the gas chromatograph. Typically,

when measuring for a gas or vapor in a workplace other chemicals will be adsorbed onto

the charcoal also. What makes the gas chromatograph so helpful is the ability to

simultaneously separate and measure all the compounds in the solvent mixture (White,

Taylor, Mauer, and Kupel, 1970). NIOSH recommends flame ionization or electron

capture gas chromatography. Flame Ionization Detectors (FID) are a type of gas detector

that uses a flame to ionize the solution passing through the GC, while an Electron

Capture Detector (ECD) uses a radioactive beta particle emitter in place of the flame to

detect molecules by measuring the change in current between the collector anode and

17

cathode in the sample solution. The current is changed because electrons are being

captured, and these signals are what translates into the concentrations being measured.

Although complete recovery of the analyte from the sampler is desired, at a minimum,

the estimated recovery of the analyte from the collection medium should be greater than

or equal to 75% for concentrations equivalent to sampling 0.1, 0.5, 1.0, and 2.0 times the

exposure limit (Kennedy, Fischbach, Song, Eller, and Shulman, 1996). The disadvantages

of using GC analysis are the solvent desorption of the contaminants is not always 100%

and carbon disulfide is extremely toxic and flammable (Peach and Carr, 1986).

2.1.4 Error Associated With Sampling

During sampling and analysis for gases and vapors there is error introduced in

various steps of the methods. NIOSH's Guidelines for Air Sampling and Analytical

Method Development and Evaluation states that for any method to be considered valid, it

has to evaluate whether, on average, over a concentration range of 0.1-2.0 times the

exposure limit, the method will provide a result that is within ±25% of the true

concentration 95% of the time with the absolute bias being less than 10% (Kennedy,

Fischbach, Song, Eller, and Shulman, 1996). For example, if an experiment had a known

concentration of a contaminant to be 100 ppm, and an industrial hygienist were to

measure between 75 ppm and 125 ppm 95% of the time, then that method could be

considered acceptable. Exposure assessment consists of an evaluation of the method,

pre-sampling procedures, post-sampling procedures, and analysis of the sample. The pre-

and post-sampling procedures, along with the analysis of the sample have uncertainties

18

associated with them. NIOSH published a table in their Sampling Strategy Manual that

can be seen in Table 2.2. The table shows the required accuracy for a method at different

levels of concentrations. If the concentration is lower than the action level, a method

only needs to be 50% accurate.

Table 2.2: Required Accuracy For Specific Concentration Levels (Leidel, Busch, and

Lynch, 1977)

Concentration Required

Accuracy

Above Permissible Exposure Limit ±25%

At or below the Permissible Exposure

Limit and above the Action Level ±35%

At or below the Action Level ±50%

Crisp (1980) suggested seven criteria for a successful sampling procedure:

1) Accuracy and precision of combined analytical and collection procedures for

concentrations ranging from 0.1-2.0 TLV to be within ±16% of true

concentrations at the 95% confidence level;

2) Total recovery efficiency at least 75%;

3) Bias between total recovery and desorption efficiency less than ±10%;

4) Capability of taking 10-15 min samples at ceiling and excursion levels;

5) Minimum sampling time of 1 hour, preferred 4-8 hours for TWA;

6) Stored samples should compare within ±10% relative to initial samples after

being stored for 14 days; and

7) The flow rate of the sampling pump should be known with an accuracy of

±5%.

19

The value NIOSH derived for pump and calibration error is commonly assumed

to be 5% (Perkins, 1997). Other sources of error include loss of sample to the walls of

tubes and sample holders through adsorption. When first beginning to sample for an

organic gas or vapor, some of the molecules will adsorb to the walls of the rubber hose

until equilibrium is reached. Lastly, a comprehensive survey of several compounds over

the range of 0.6x TLV to its 15 minute short term exposure limit (STEL) was done, and it

concluded that total relative error was 12.7% split between analytical and sampling error

(Crisp, 1980).

2.2 Overall Benefits of the Study

The results of this study would indicate whether or not sample holders when used

to measure gases and vapors with carbon sorbent tubes were causing differences in

measured concentrations. It also would help show the effects of flow rate, pump type,

exposure profile, vapor properties, and if the sample holder is mounted on a mannequin

or free hanging stand, on measured concentrations. If the results determined that

measured concentrations had differences greater than 10% with and without a sample

holder, possible future research would be to provide models for adjustments that could be

made to adjust the concentrations.

20

2.3 Specific Aims

The specific aims of this study were as follows:

1.) Examine whether there are significant differences (>10%) between

concentrations measured using activated carbon sorbent tubes with three

different sample holder configurations: a) no sample holder - charcoal tube

facing upward with end open to ambient atmosphere, b) using an SKC-brand

sample holder, and c) using an A.P. Buck-brand sample holder.

2.) Characterize the nature of any significant effects by examining different

vapors spanning a range of chemical/physical properties (e.g., polarity, BP,

VP), different types of sampling pumps (pulsating stroke-counter type vs.

continuous type pumps), different vapor exposure profiles (variable vs.

relatively constant), and different sampling flow rates (200 mL/min vs. 30

mL/min).

3.) Propose and evaluate mechanisms governing any identified effects.

21

Chapter 3

Methods

This section outlines the instrumentation and procedure used in this study. Based

on a previous study using the vapor generation chamber, it was decided to use the same

conditions in the chamber for exposure profiles. The conditions had to be modified

slightly, and a preliminary test atmosphere generation test was done with the chamber to

ensure that both vapors being used were approximately the same concentration averaged

over time. The experimental setup included continuous and pulsating pumps to measure

the concentrations, and a PID to measure a reference concentration in the chamber, which

could be later used as a comparison. There were a total of 24 sample runs, which

combined all of the factors with one another. All of the samples were collected and then

analyzed using a gas chromatograph (GC) with a flame ionization detector (FID).

3.1 Preliminary Test Atmosphere Generation Tests

To compare the sampled concentrations between the two types of vapors being

used (n-hexane and m-xylene), preliminary tests were conducted to configure the vapor

generation system so that both vapors had the same average concentration over the

sampled time. To keep the experiment safe, 15 PPM was chosen as the target

concentration for both vapors, which was well below OSHA's PEL's (Table 3.1). To

produce these concentrations, changes in the water bath temperature and flow rate

through the gas washing bottle had to be adjusted.

22

Table 3.1: Chemical Properties and Exposure Limits for n-Hexane and m-Xylene

Property n-Hexane m-Xylene

Molecular Formula C6H14 C8H10

Molecular Weight 86.18 g/mol 106.16 g/mol

Vapor Pressure 124 mm Hg 8 mm Hg

Boiling Point 69 °C 139 °C

OSHA PEL 500 ppm 100 ppm

ACGIH TLV 50 ppm 100 ppm

The constant exposure profile for m-xylene was tested first. For a constant

exposure profile the vapor generation system was turned on at a specific setting, and the

concentration was allowed to reach equilibrium in the chamber. A PID was placed in the

chamber, visible through a window, to monitor the concentration. Initially, the

temperature and flow rate were used from the previous study to determine a baseline

concentration. The first concentration was found to be 35 PPM, so a reduction in the

flow rate was done, and trials continued until 15 PPM was reached. Since the variable

exposure profile consisted of the gas generation system being turned on for 10 minutes

and then off for 10 minutes; 20 minute trial runs were done so that the average PID

reading was 15 PPM. The same procedure was done with n-hexane.

It was determined that for m-xylene a water bath temperature of 55°C would be

used for both constant and variable exposure profiles. A flow rate of 1.85 L/min was

used for the constant exposure profile, while a flow rate of 4.07 L/min was turned on and

23

off for the variable profile. Since n-hexane is more volatile than xylene, lower

temperatures and flow rates were needed to reach the 15 PPM concentration. The

temperature of the water bath containing n-hexane was 27°C, just above room

temperature. The flow rate used for the constant exposure profile was 0.150 L/min, and

0.415 L/min for the variable exposure profile. The flow rates were adjusted using

LabVIEW and will be discussed later in the procedure.

Table 3.2: Parameters for Test Atmosphere Generation

Parameter m-xylene n-hexane

Water Bath Temperature 55 °C 27 °C

Flow Rate for Constant

Exposure Profile

1.85 L/min 0.150 L/min

Flow Rate for Variable

Exposure Profile

4.07 L/min 0.415 L/min

3.2 Equipment and Instrumentation

The following section will describe all of the equipment and instrumentation

used in this study. There were no human subjects used in this study.

3.2.1 SKC and Buck Sample Holders

The two types of sample holders chosen for this project were SKC- and A.P.

Buck-brand sample holders. The holders consisted of an adjustable flow holder where

the carbon sorbent tube was attached, and a plastic cover was used to go over the tube.

24

The adjustable flow holder used a needle valve to better regulate the flow passing through

the sorbent tube. One can use the sample pump to acquire approximately the target flow

rate, and make further adjustments using the needle valve to obtain the exact flow rate

needed.

The SKC holder (SKC Single Adjustable Low Flow Tube Holder #224-26-01)

was combined with a constant pressure controller (SKC Low Flow CPC #224-26CPC-10)

to be used for low-flow applications on the continuous pumps. The protective tube cover

(SKC Type B Protective Tube Cover #224-29B) can be seen in Figure 3.1. Each SKC

holder was labeled and used in both continuous and pulsating pump experiments.

Figure 3.1: SKC Sample Holder

Two types of Buck Holders were used because of the limitations with the flow

adjustments when combined with the pulsating pump. The valve inside the adjustable

low-flow sample holder (A.P. Buck Inc #APB-109030) would not operate correctly at

low flow rates with the pulsating pump, so a similar non-adjustable low-flow holder had

to be used (A.P. Buck Inc #APB-109032). Both sample holders looked and operated the

25

same; the only difference was one could not be adjusted and had to be used with the

pulsating pumps. Figure 3.2 shows an image of the adjustable buck sample holder.

Figure 3.2: Adjustable Buck Sample Holder

Activated carbon sorbent tubes (SKC #226-01) were used throughout the entire

study. Each tube was pre-labeled with the date, experiment run number, and a number

showing where it was positioned in the chamber. The location in the chamber indicates

where on the mannequin or free-hanging sampler the sample was hung. An example

label would be 9-6, indicating that the sorbent tube was used in experiment 9, and

positioned farthest to the right. The sorbent tubes were stored after sampling in a freezer

until analysis could be done.

3.2.2 Continuous and Pulsating Pumps

Six of each type of sampling pump (continuous, pulsating) were used for

measuring the concentrations in the chamber. The two models of pumps used were the

continuous pump (SKC AirLite #110-100) and pulsating pump (SKC 222 Series Pump

26

#222-3). Each pump was labeled to make it easier when pre- and post-calibrating the

pumps.

Calibrating the pumps was done using a primary standard before and after each

experimental run with a DryCal electronic flowmeter (BIOS DryCal DC-Lite DCL-M).

The pulsating pumps had re-chargeable batteries, which were fully charged after every

run. The continuous pumps operated on 4 AA batteries, which were swapped out after

approximately 250 minutes of operation. Figure 3.3 shows both pumps along with the

DryCal used in the study.

Figure 3.3: Pulsating Pump (left), DryCal, and Continuous Pump (right)

Initially, each pulsating pump was also calibrated using a bubble buret and stop

watch combination to determine the flow rate (mL/stroke). When calibrating the

pulsating pumps for trial runs, the beginning counter strokes were recorded along with

the final counter strokes after the experiment, and the volume was calculated. These

27

volumes were then compared with the volume calculated using the DryCal flow rates. In

every experiment both volumes sampled were within 5% and thereafter the flow rates

were determined using the DryCal only.

3.2.3 Photo Ionization Detector (PID)

A PID (MiniRAE 2000) was used to record chamber concentrations at one-second

intervals during experimental runs. The PID was calibrated before each run according to

manufacturer's instructions using 100 ppm isobutylene span gas, and then a correction

factor was used to adjust for the two vapors being used. A 10.6 eV lamp was used in the

PID, which gave correction factors of 4.3 and 0.43 for m-xylene and n-hexane,

respectively. After every run, the PID was connected to a computer, and a plot of

concentration versus time was displayed and saved. Details on each run were also saved

including the highest and average concentrations. An image of the PID used throughout

this study is shown in Figure 3.4.

Figure 3.4: MiniRAE 2000 PID

28

3.2.4 Exposure Chamber and Gas Generation System

The exposure chamber and gas generation system were the same used in the

previous study. The gas generation system was controlled using a program in LabVIEW

(Student Version 8.2) written by Brandon Lin (PhD - Industrial Engineering). The

designed program used a mass flow controller to control the flow rates being passed

through the gas bubbler. The vapors leaving the bubbler would then enter a dilution

stream to pass through the test chamber. The program allowed the user to enter voltages,

which related to specific flow rates that could be turned on for appropriate durations of

time. This is how the constant and variable exposure profiles were obtained.

An image of the water bath and gas washing bottle used can be seen in Figure 3.5.

Figure 3.6 is a schematic that shows how the chamber operated. The chemical being

used would be filled in a gas washing bottle and placed in the water bath set to the pre-

determined temperature. The mass flow controller, operated by LabVIEW, would send a

known flow rate through the gas washing bottle pushing the vapor into a diluted stream

of fresh air. The vapor was pushed through the chamber using a blower, and an exhaust

fan on the other side of the chamber would pull the air out into a hood.

29

Figure 3.5: Water Bath with Gas Washing Bottle

The frame of the chamber was made from wood and was 4.5 ft x 6 ft x 9 ft (243

ft3). It was sealed tightly with plastic vinyl wrap to minimize leakage from the chamber.

The supply and exhaust blowers were adjusted to keep the chamber under negative

pressure. This ensured that if there were any leaks the vapor would still stay in the

Dilution Air

Supply Blower

Compressed

Air

Dynamic Test Atmosphere

Generation System

Exposure Chamber

Exhaust Blower

Figure 3.6: Test Atmosphere Generation System

30

chamber. Inside the chamber was a light to see when setting up the sample trains and a

small stand to set the pumps on during operation. Figure 3.7 shows an image of the

actual chamber used.

Figure 3.7: Actual Chamber Used in the Study

3.3 Experimental Design

A multi-factorial analysis design was used for this study to account for the

different levels of each contributing factor in the experiment. This design was developed

in consultation with James Slaven (Biostatistics and Epidemiology Branch, HELD,

NIOSH). There were five effects, and each effect was broken into two levels as seen in

Table 3.3.

31

Table 3.3: Effects Examined in Multi-Factorial Design

Effect / Factor Level 1 ( - ) Level 2 ( + )

Vapor Low Boiling Point

(n-hexane)

High Boiling Point

(m-xylene)

Pump Type Pulsating Continuous

Exposure Profile Variable Constant*

Flow Rate Low (~30 mL/min) High (~200 mL/min)

Mannequin Yes No (free hanging)

*For constant exposure profile experiments short and long term samples were collected

A resolution V design was used to yield results so that all of the main effects or

two-factor interactions would not be aliased with any other main effect or two-factor

interaction. This type of design gives a study-design matrix with 16 experimental runs

noted in Table 3.4.

The last factor examined was the type of sample holder used. The three types of

sample holders were an open sorbent tube, a SKC brand sample holder, and a Buck brand

sample holder. To study the effect of each sample holder, two duplicate sampling units

for each of the three sample holder types were used in every experimental run resulting in

six measured concentrations per run. For example, Run 1 from Table 3.4 would include

n-hexane, a pulsating pump, variable concentration exposure profile, a low sampling flow

rate, and mounting the sampler on a mannequin. This experimental run will then have

six samplers, two each for the three sample holder types. The study design matrix is

given in Table 3.4, but the actual run order was randomized to transform any systematic

effects that could not be controlled.

32

Table 3.4: Study Design Matrix

Run Vapor Pump Exposure Flow Mannequin Long and Short

Duration Samples

1 - - - - + no

2 + - - - - no

3 - + - - - no

4 + + - - + no

5 - - + - - yes

6 + - + - + yes

7 - + + - + yes

8 + + + - - yes

9 - - - + - no

10 + - - + + no

11 - + - + + no

12 + + - + - no

13 - - + + + yes

14 + - + + - yes

15 - + + + - yes

16 + + + + + yes

When the exposure profile was constant, an additional factor, duration, was

included as a blocking effect. A regular run, whether it is variable or constant exposure,

is 81-minutes long. To identify whether sampling time affects the concentrations

measured with and without a sample holder, short sampling time data was collected just

for the constant exposure profile. The short experimental runs were 33-minutes long, and

there were 8 of these, which resulted in a combined 24 experimental runs for the entire

project.

33

3.4 Experimental Procedure

A test-atmosphere generation system and exposure chamber were used for the

evaluation of the sample holders and are depicted in Figure 3.6. The vapor was generated

using a gas washing bottle containing either n-hexane or m-xylene in a water bath kept at

a constant temperature. The temperature for each vapor was determined by trial runs to

get both vapor concentrations approximately 15 ppm. The mannequin or free hanging

sampler was placed in the exposure chamber according to the planned sampling designs.

The six different sample holders were also randomly placed two inches apart forming a

straight line across the mannequin or free hanging sampler for each scenario. The sample

holders were randomized by assigning each sample train an ID and using a random

number generator to choose the order they were placed on the mannequin or free hanging

stand. Figure 3.8 shows the mannequin and free hanging stand used with the six

sampling trains attached. The sample holders were oriented on the mannequin as they

would be in an industrial sampling scenario, and on each stand the level of air entry was

adjusted to be approximately four feet off the ground.

34

Figure 3.8: Mannequin and Free Hanging Stand

For constant exposure profiles the bubbler was turned on with a set flow rate and

allowed to run for 80 minutes for long runs and 30 minutes for short runs. A typical

exposure profile is presented in Figure 3.9. The variable exposure profile was generated

by turning on and off the compressed air through the bubbler every ten minutes to

produce a concentration profile similar to that shown in Figure 3.10.

Figure 3.9: Constant Concentration Exposure Profile for Vapors

0

4

8

12

16

0 10 20 30 40 50 60 70 80

Co

nce

ntr

atio

n (

PP

M)

Time (min)

35

Figure 3.10: Variable Concentration Exposure Profile for Vapors

Both types of air sampling pumps were pre- and post-calibrated using a Drycal for

every experiment. After the pumps were pre-calibrated for each run, a calibrated PID

was placed in the chamber to record the vapor concentration profile, which could be later

plotted for analysis and compared to sample results. The pumps were each given a

specific sample holder and a labeled carbon sorbent tube that was placed on each pump

connected by a rubber hose. The sample trains were then placed in the chamber and

either attached to the mannequin as they would be in real practice or placed on the free

hanging stand. An electronic thermometer was also placed in the chamber, and the

beginning and ending temperature and humidity was recorded. The selected test

atmosphere and pumps were then turned on for the duration of the experimental run.

Calibration standards and quality control samples were prepared and analyzed

with each set of experimental samples. The sorbent tubes were analyzed on site using a

Gas Chromatograph and Flame Ionization Detector. All statistical tests were compared

to a alpha value of 0.05. Once the results were obtained, a data summary table was sent

to James Slaven (Biostatistician, NIOSH) for statistical analysis.

0

5

10

15

20

25

30

0 20 40 60 80

Co

nce

ntr

atio

n (

PP

M)

Time (min)

36

Chapter 4

Results and Discussion

Sample holders are used every day by Industrial Hygienists when taking personal

samples in a workplace. No research has been presented on whether or not these sample

holders could be affecting measured concentrations. The purpose of this study was to

evaluate whether or not sample holders, when operating under specific conditions, will

give significantly different measured concentrations. The study first examined the

individual factors affecting the measured concentrations. Secondly, a test using a ratio of

the sample holder results combined with the open sample tube concentrations was used to

determine any differences in sample holder concentrations. Lastly, the study looks at

how a PID measuring real-time concentrations compares to actual measured samples.

4.1 Individual Factor Results Using Measured Concentrations

Individual effects on concentration were analyzed using the multi-factorial design.

Each effect had two levels, excluding the sample holder and positioning in the chamber,

which had three and six levels, respectively. The mean concentration for each level was

compared to the opposite levels (e.g. high vs. low flow rate) using an Analysis of

Variance. Table 4.1 summarizes the ANOVA results for every factor using the

measured concentrations. The three variables that gave significant results were the

duration of the experiment, the type of pump used, and the vapor that was used. All three

factors had p-values less than 0.0001.

37

Table 4.1: Analysis of Variance Results for Concentration (significant factors in bold)

Source DF Seq SS Adj SS Adj MS F p

Vapor 1 52.032 52.032 52.032 35.51 0.000

Pump Type 1 29.666 29.666 29.266 20.25 0.000

Exposure Profile 1 30.329 0.920 0.920 0.63 0.429

Flow Rate 1 0.039 0.039 0.039 0.03 0.871

Mannequin 1 1.392 1.392 1.392 0.95 0.331

Duration 1 58.064 58.064 58.064 39.63 0.000

Holder 2 5.474 4.880 2.440 1.67 0.193

Position 5 0.262 0.262 0.052 0.04 0.999

Error 130 190.465 190.465 1.465

Total 143 367.723

It can be noted that the sample holders had no significant difference when testing

the concentrations. Figure 4.1 is a main effects plot that shows how the concentrations

for each factor compare to one another. It shows the mean concentration for each level

and compares it to the opposite level. For example, when looking at the vapor factor, the

mean concentration of n-hexane was lower than the mean concentration of m-xylene.

38

Me

an

of

Co

nce

ntr

ati

on

PP

M

Xy leneHexane

14.4

13.6

12.8

PulsatingC ontinuous V ariableC onstant

LowHigh

14.4

13.6

12.8

YesNo 83 Min33 Min

SKCO pen TubeBuck

14.4

13.6

12.8

654321

V apor Pump Ty pe Exp. Profile

F low Rate Mannequin Duration

Holder Position

Main Effects Plot (data means) for Concentration PPM

Figure 4.1: ANOVA Results for Concentration (PPM) as a Response Variable

Another ANOVA was then done using the concentrations, but this time including

interaction terms using the three significant factors from Table 4.1. These results along

with an interaction plot can be seen in Table 4.2 and Figure 4.2. The only interaction

term that was significant was the vapor*duration term with a p-value equal to 0.000. An

interaction plots is a graph that measure the interaction between the means of two factors,

with the second factor held constant. Parallel lines in an interaction plot indicates no

interaction, while the larger the slopes of the two lines become, the higher the degree of

interaction.

39

Table 4.2: Analysis of Variance for Concentration with Interaction Terms

Source DF Seq SS Adj SS Adj MS F p

Vapor 1 52.032 52.032 52.032 90.87 0.000

Pump Type 1 29.666 29.666 29.266 21.80 0.000

Exposure Profile 1 30.329 0.920 0.920 0.94 0.335

Flow Rate 1 0.039 0.039 0.039 0.04 0.843

Mannequin 1 1.392 1.392 1.392 1.42 0.236

Duration 1 58.064 58.064 58.064 59.12 0.000

Holder 2 5.474 4.880 2.440 2.48 0.087

Position 5 0.262 0.262 0.052 0.05 0.998

Vapor*Pump Type 1 0.397 0.397 0.397 0.40 0.526

Vapor*Duration 1 63.019 63.019 63.019 64.17 0.000

Pump Type*Duration 1 2.326 2.326 2.326 2.37 0.126

Error 127 190.465 124.723 0.982

Total 143 367.723

VaporVapor

15.0

13.5

12.0

Pump T ypePump T ype

DurationDuration

83 Min33 Min

PulsatingC ontinuous

15.0

13.5

12.0

Xy leneHexane

15.0

13.5

12.0

Vapor

Hexane

Xylene

Pump Type

Continuous

Pulsating

Duration

33 Min

83 Min

Interaction Plot (data means) for Concentration PPM

Figure 4.2: Interaction Plot for Vapor, Pump Type, and Duration Factors

40

For the duration results, the longer the run was the higher the mean concentration

was in the chamber. This effect most likely happened because the concentration in the

chamber would slowly drift higher the longer the sample ran, and this drifting could not

be controlled. The concentrations were attempted to be balanced out using the LabVIEW

software and slowly decreasing the flow rate through the bubbler as time progressed, but

doing this only added small fluctuations in the concentration profile. During the

preliminary test runs, the profiles were designed to average 15 ppm over the sampling

time. Figure 4.3 shows the PID concentration in the chamber for a long run (81 min).

Over the 81-minute experiment, the vapor concentration continues to rise until the end of

the experiment when the gas generation system was turned off, yet it yielded an average

concentration of 15.6 PPM.

Figure 4.3: Measured PID Concentration for Run 4L in Experimental Design.

The graph shows the constant drift in concentration as time progressed.

0

2

4

6

8

10

12

14

16

18

20

0 10 20 30 40 50 60 70 80

Concentr

ation (

PP

M)

Time (Minutes)

41

The pump type had a significant effect on the concentration, resulting in the

continuous pump giving an overall higher mean concentration than the pulsating pump.

At first, differences in flow rates between the pumps were thought to be causing this, but

flow rates were shown to provide almost the exact same mean concentration. Evidence

for this pump type effect could not be determined.

The vapor factor concentrations may have differed due to the higher volatility of

n-hexane when compared with m-xylene. Since n-hexane has a higher volatility than m-

xylene, one would believe that n-hexane would reach equilibrium faster in the chamber

resulting in higher concentrations. However, the interaction plot above shows n-hexane

has a lower average concentration than m-xylene. The time it took for both vapor

concentrations to reach approximate equilibrium has been plotted in Figure 4.4. It is

difficult to tell actually when equilibrium was reached because of the constant drift in the

chamber, but from the graphs it can be noted that around six minutes into n-hexane's run

the concentration started flattening out. M-xylene's concentration started to flatten out

after approximately eight minutes. Both experiments were 81-minute runs, and the data

shows that n-hexane does indeed reach equilibrium faster than m-xylene. These results

would lead one to believe that n-hexane should have a higher average concentration than

m-xylene, which was not the case. The decay of concentration was then examined to see

how fast each vapor exited the chamber once the vapor generation system was turned off.

42

Figure 4.4: Concentration Rise of Both Vapors in the Experimental Chamber

During phases in the experiment when the gas generation system would be turned

off, the PID showed the concentration of hexane would drop faster than xylene. This

could cause n-hexane to have a much lower overall mean concentration, and would

explain the significant differences between the two concentrations. Figure 4.5 shows

how fast the concentration of n-hexane and m-xylene would decrease after the vapor

generation system was turned off. N-hexane would reach approximately 0 ppm about

two minutes faster than m-xylene. Volatility is one possible explanation for the

differences in vapor concentrations.

0

2

4

6

8

10

12

14

0 5 10

Co

nce

ntr

atio

n (

PP

M)

Time (Minutes)

m-Xylene

0

2

4

6

8

10

12

14

16

0 5 10

Co

nce

ntr

atio

n (

PP

M)

Time (Minutes)

n-Hexane

43

Figure 4.5: Rate of Decrease in Vapor Concentration

Lastly, when looking at the interaction terms from Table 4.2 the Vapor*Duration

interaction term was significantly different. This could also support the above statements

indicating a difference in volatility and time a sample was in the chamber. This

difference could be from each vapor taking longer to reach maximum in a chamber

(Figure 4.4), the vapor taking longer to dissipate from the chamber (Figure 4.5), or a

combination of both.

The significant differences when looking at just the concentrations of the vapors

is hard to designate whether they are significant, because the vapor generation system

differed from day-to-day experiments. All experiments were done during the summer

months when temperature and humidity were fluctuating, and this resulted in the chamber

producing different concentrations ranging from 12-16 PPM each day. It was decided to

use a ratio of concentrations for each separate day to further analyze the results using the

open tube sampler as a reference tube.

0

5

10

15

20

25

30

35

0 50 100 150 200

Co

nce

ntr

atio

n (

PP

M)

Time (Seconds)

Xylene

Hexane

44

4.2 Individual Factor Results Using a Ratio of Measured Concentrations

After noting these significant results, each effect was then tested using a ratio of

concentrations between the SKC or A.P. Buck sample holder and the open sample tube.

By using this ratio, the open sample tube becomes the reference tube concentration to

which the other two sample holders can be compared. By doing this, it negates the day-

to-day variations in the chamber concentrations. All factors, including the sample

holders, were then analyzed using an ANOVA test. Table 4.3 shows the results of the

ANOVA test, indicating flow rate and the sample holders to have significant differences

with p-values equal to 0.006 and 0.021, respectively. A main effects plot, Figure 4.6,

shows the graphical results of the ANOVA comparing the two levels of each factor.

Using this ratio method, the factors that were significant when looking at just the

concentrations are no longer significant, and this method shows that sample holders may

be causing differences in measured concentrations.

45

Table 4.3: Analysis of Variance Results for Ratio of Concentrations (significant factors in

bold)

Source DF Seq SS Adj SS Adj MS F p

Vapor 1 0.001 0.001 0.001 0.25 0.618

Pump Type 1 0.006 0.006 0.006 2.27 0.139

Exposure Profile 1 0.006 0.008 0.008 3.04 0.089

Flow Rate 1 0.023 0.023 0.023 8.43 0.006

Mannequin 1 0.000 0.000 0.000 0.08 0.782

Duration 1 0.002 0.002 0.002 0.85 0.361

Holder 1 0.015 0.015 0.015 5.77 0.021

Error 40 0.107 0.107 0.003

Total 47 0.160

Me

an

of

Ra

tio

Xy leneHexane

1.05

1.00

0.95

PulsatingC ontinuous V ariableC onstant

30 mL/min200 mL/min

1.05

1.00

0.95

YesNo 80 min30 min

SKCBuck

1.05

1.00

0.95

V apor Pump Ty pe Exposure Profile

F low Rate Mannequin Duration

Holder

Main Effects Plot (fitted means) for Ratio

Figure 4.6: ANOVA Results for Ratio of Concentrations as a Response Variable

46

Interaction terms between the two significant factors were also examined and can

be seen in Table 4.4. In this case, the interaction between flow rate and the type of sample

holder was not significant, but an interaction plot can also be seen in Figure 4.7 to

compare the two factors.

Table 4.4: Analysis of Variance Results for Ratio of Concentrations with Interaction

Terms

Source DF Seq SS Adj SS Adj MS F p

Vapor 1 0.001 0.001 0.001 0.25 0.618

Pump Type 1 0.006 0.006 0.006 2.27 0.139

Exposure Profile 1 0.006 0.008 0.008 3.04 0.089

Flow Rate 1 0.023 0.023 0.023 8.43 0.006

Mannequin 1 0.000 0.000 0.000 0.08 0.782

Duration 1 0.002 0.002 0.002 0.85 0.361

Holder 1 0.015 0.015 0.015 5.77 0.021

Flow Rate*Holder 1 0.003 0.003 0.003 1.26 0.269

Error 39 0.104 0.104 0.003

Total 47 0.160

47

Flow RateFlow Rate

HolderHolder

SKCBuck

1.06

1.04

1.02

1.00

0.98

30 mL/min200 mL/min

1.06

1.04

1.02

1.00

0.98

Flow Rate

200 mL/min

30 mL/min

Holder

Buck

SKC

Interaction Plot (data means) for Ratio

Figure 4.7: Interaction Plot for Flow Rate and Sample Holder

The flow rate was a significant factor in both sample holder cases and was

believed to be caused from a decrease in flow for the high flow rate experiments. In both

sample holder cases, the higher flow rate resulted in smaller ratios when compared to the

low flow rate. When pre- and post-calibrating for the low flow rate the pumps seemed to

stay consistent throughout the entire experiment. During high flow rate runs, it was noted

that sometimes the post calibration flow rate would drop 2% to 5%. Fluctuations of flow

rates of less than 5% is allowable according to NIOSH's methods. These differences in

flow rates could lead to smaller measured concentrations, resulting in the average flow

rate being smaller than it was intended to be. This drop in flow rate may have resulted

from batteries losing charge during the experiment. The pulsating pumps had

rechargeable battery packs that could be charged to full at the end of every day. The

48

continuous pumps used four AA batteries and would be swapped out every 3 runs. It is

possible that during the third run, diminishing battery lives began to affect the flow rate

of the pump.

Lastly, the ratio ANOVA test did show a significant difference between sample

holders, and this was one of the main points of this research. A closer look using a T-test

study will examine these differences in the next section.

4.3 Overall Sample Holder Results

The following results determined if either of the two sample holders were

measuring a significantly different concentration when compared to the open sample

holder. This was done by taking the ratio between the open holder concentration and the

other two sample holder concentrations. A T-test was performed to see if the

concentration ratios were one, meaning no difference in concentrations. Table 4.6 gives

the mean ratio of concentrations, standard deviation, and T-test p-value, which was

compared to a significant value of 0.05. The p-value for the ratio between open holder

and buck holder was 0.0382, indicating that the ratio of concentrations differ significantly

enough from one. The mean value of the ratio was 1.02, showing that the Buck holder

usually gave a larger concentration than the open holder. The opposite is true for the

mean ratio between the open holder and SKC holder. It had a smaller value than one, but

the p-value was 0.0651, indicating insignificance.

49

Table 4.5: Ratio of Open and Sample Holder

SKC Holder/Open Holder Buck Holder/Open Holder

Mean Ratio 0.99 1.02

Standard Deviation 0.04 0.08

T-test p-value 0.0651 0.0382

This first set of data shows that the Buck sample holder is in fact giving larger

readings than an open-faced sorbent tube. This table did not take into account any other

factors besides the sample holder used. Even though the Buck holder did give a

significant difference in concentration, the difference of 2% is small when compared to

other sources of error associated when sampling for vapors. NIOSH’s Occupational

Exposure Sampling Strategy Manual estimates the error associated with pump and

calibration is 5%. There is also error introduced when using the Gas Chromatograph and

Flame Ionization Detector that varies from 5% to 10% depending on the equipment used.

Overall, a method of measuring air concentration should be within ±25% of the true

concentration 95% of the time. There is error built into these sampling strategies, and the

small 2% from these results is not large enough to state that sample holders caused the

differences in measured concentrations.

The statistical results do say that the difference is significant, but in real world

industrial hygiene applications a difference of more than 10% would have been around

the significance needed to indicate that sample holders were having an impact on

measured concentrations.

50

4.4 Comparing Sampled Concentration vs. Measured PID Concentration

The data collected during this study gives a good opportunity to test the

performance of a PID. Depending on the PID, error may be introduced by temperature,

humidity, other gases present, and calibration error. Two tests were done to determine if

the measured PID concentrations were equal to the sample concentration results to

examine the PID accuracy. The first test performed was a two sample T-test comparing

the measured concentrations with the PID concentrations. Table 4.7 shows the results of

the test, and Figure 4.8 gives an interval plot to show the range of concentrations. The p-

value was 0.000, indicating that the means of the two concentrations significantly

differed.

Table 4.6: T-test Comparing Measured Concentration vs. PID Concentration

N Mean St. Dev. T-Value p-value

Measured Concentration 144 13.49 ppm 1.60 ppm 4.50 0.000

PID Concentration 144 14.34 ppm 1.59 ppm

51

Co

nce

ntr

ati

on

(P

PM

)

PID Conc.Concentration

15.0

14.5

14.0

13.5

13.0

Interval Plot of Concentration, PID Conc.95% CI for the Mean

Figure 4.8: Interval Plot Comparing Means of Measured Concentration and PID

Concentration

However, just as when studying the sample holders, day-to-day variations in the

vapor chamber concentrations could be affecting the means of both measured and PID

concentrations. A T-test was performed on the ratio (ratio = measured concentration/PID

concentration) of the two concentrations to examine if the PID and measured

concentrations were equal. Results of the T-test can be seen in Table 4.8. The 95%

confidence interval was equal to 0.93 to 0.97, and a p-value equal to 0.0001. This

indicates the ratio significantly differs from 1, and the PID concentrations are generally

larger than the sample concentration.

Table 4.7: One-Sample T-test Comparing Ratios of Measured and PID Concentrations

Variable N Mean St. Dev. 95% C.I.

Ratio of

Concentrations 144 0.95 0.13 0.93 - 0.97

52

Even though significantly different results have been shown for both T-tests

above, the PID typically measures within 5% of the measured sample concentration.

Since PID's are becoming more and more popular for sampling for gas and vapors in the

workplace, this result is promising that they are performing with respectable accuracy.

53

Chapter 5

Conclusions

The objective of this project was to study the effects sample holders have on gas

and vapor sampling with activated carbon sorbent tubes, and to identify factors that may

produce differences in concentrations when compared to a sample train without a sample

holder.

The results suggest that sample holders do affect measured concentrations, but

have such a small effect when considering the amount of error and uncertainty already

associated with the methods of sampling for vapors and gases. The A.P. Buck sample

holder measured a +2% difference in sample concentration when compared to an open

sorbent tube, while the SKC sample holder had a -1% difference. It cannot be

determined if this error came from the sample holder or is just part of the built-in error of

sampling and analytical error. It can be concluded that using a sample holder to protect a

worker from getting injured will not make a noticeable difference in the actual

concentration sampled.

Effects such as flow rate and pump type showed significant results when sampling

with sample holders, but again the difference is minimal and will not practically affect

the final concentrations being measured. It should also be noted that PID devices, such

as the MiniRAE 2000, give good representation to the actual concentrations of the air

being sampled.

54

References

Anderson, K., Levin, J.O., Lindahl, R., Nilsson, C.A. (1984). Influence of Air Humidity on

Sampling Efficiency of Some Solid Adsorbents Used for Sampling Organics from Work-

Room Air. Chemosphere , 13 (3), 437-444.

Crisp, S. (1980). Solid Sorbent Gas Samplers. The Annals of Occupational Hygiene , 47-76.

Cullis, C. F., Firth, J. G. (1981). Detection and Measurement of Hazardous Gases.

London: Heinemann.

Guenier, J., and Muller, J. (1984). Sampling of Gaseous Pollutants on Activated Charcoal with

900 mg Tubes. The Annals of Occupational Hygiene , 28 (1), 61-75.

Kennedy, E. R., Fischbach, T. J., Song, R., Eller, P. M., Shulman, S. A. (1996). Summary of

the NIOSH Guidelines for Air Sampling and Analytical Method Development and

Evaluation. The Analyst , 121, 1163-1169.

Lee, Larry, Flemmer, Michael, Lee, Eun Gyang, Harper, Martin, Lin, Ming-I, Groves, William,

Frievalds, Andris, Slaven, James. A Novel Physiologic Sampling Pump Capable of Rapid

Response Breathing. J. Environ. Monit., 2009, 11, 1020 - 1027, DOI: 10.1039/b816699d.

Leidel, N. A., Busch, K. A., Lynch, J. R. (1977). NIOSH. Occupational Exposure Sampling

Strategy Manual. Cincinnati: Superintendent of Documents.

Levin, J. O., Carleborg, L. (1987). Evaluation of Solid Sorbents for Sampling Ketones in Work-

Room Air. The Annals of Occupational Hygiene , 31 (1), 31-38.

Lin, Ming-I, Groves, William A., Freivalds, Andris., Lee, Eun Gyang, Harper, Martin, Slaven,

James E., and Lee, Larry. Exposure Assessment by Physiologic Sampling Pump -

Prediction of Minute Ventilation Using A Portable Respiratory Inductive

Plethysmograph System, J. Environ. Monit., 2008, 10, 1179 - 1186, DOI:

10.1039/b806292.

55

Lin, Ming-I, Groves, William A., Freivalds, Andris., Lee, Larry, Lee, Eun Gyang, , Slaven,

James E., and Harper, Martin. Laboratory Evaluation of a Physiologic Sampling Pump

(PSP). J. Environ. Monit., 2010, DOI: 10.1039/b923986c.

Mintz, Benjamin W. "History of the Federal Occupational Safety and Health

Administration."Fundamentals of Industrial Hygiene. By Barbara A. Plog and Patricia

Quinlan. Itasca: National Safety Council, 2002. 825-26.

Occupational Safety and Health Act of 1970: the OSH Act. Des Plaines, IL: U.S. Dept. of Labor,

Occupational Safety and Health Administration, Office of Training and Education, 1987.

Peach, M. J., Carr, W. G. (1986). Air Sampling and Analysis for Gases and Vapors. In

Occupational Respiratory Diseases (pp. 41-68).

Perkins, J. L. (1997). Modern Industrial Hygiene. New York: Van Nostrand Reinhold.

Rappaport, S. M., Kupper, L. L. (2008). Quantitative Exposure Assessment. El Cerrito, CA:

Stephen Rappaport.

White, L. D., Taylor, D. G., Mauer, P. A., Kupel, R. E. (1970). A Convienient Optimized Method

of the Analysis of Selected Solvent Vapors in the Industrial Atomsphere. American

Industrial Hygiene Association Journal , 31 (2), 225-232.

56

Appendix A

Raw Data

The following pages are the data sheets recorded for every experiment.

57

Experiment #__1__

Date ___7/02/09____

Vapor: Hexane

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder Type

CA

SKC 2

IM

Buck 1

CM

Open 2

83

SKC 1

IA

Open 1

82

Buck 2

Pre-Cal Flowrate

29.5 29.9 29 28.5 30.8 29.7

Post-Cal Flowrate

29.5 30 28.9 28.4 31.1 29.6

Initial Stroke Count

793082 95358 757270 626104 56931 845116

Final Stroke Count

798687 100453 762600 630896 62345 850146

Time Sampled 81:15

Charcoal Tube # 1 2 3 4 5 6

PID Average Concentration: ____16 PPM_____

Notes: Temperature: 70°F

Humidity: 17%

58

Experiment #__2__

Date ____7/06/09____

Vapor: ___Xylene____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No Sampling Time:

Short / Long

Pump ID & Sample Holder

Type

83 SKC 2

CM Open 2

IM Buck 2

CA Open 1

IA SKC 1

82 Buck 1

Pre-Cal Flowrate

28.1 28.9 29.6 29.3 31 29.5

Post-Cal Flowrate

28.1 29 30 29.4 31.1 29.6

Initial Stroke Count

631138 762874 100989 799122 62581 850796

Final Stroke Count

635868 768198 106081 804717 67973 856001

Time Sampled 81:19

Charcoal Tube # 1 2 3 4 5 6

PID Average Concentration: ____16.9 PPM___

Notes: Temperature: 73°F

Humidity: 16%

59

Experiment #_3S_

Date ____7/07/09____

Vapor: ____Hexane____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

B SKC 1

E Buck 2

D Open 2

A SKC 2

C Buck 1

F Open 1

Pre-Cal Flowrate 196.3 201.9 200 201.3 198.5 202.1

Post-Cal Flowrate

203.2 206.5 194.8 189.3 197.8 202.2

Initial Stroke Count

Final Stroke Count

Time Sampled 33:16

Charcoal Tube # 1S 2S 3S 4S 5S 6S

PID Average Concentration: ____12.1 PPM____

Notes: Temperature: 72°F

Humidity: 16%

60

Experiment #_3L_

Date ____7/07/09____

Vapor: ____Hexane____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

B SKC 1

E Buck 2

D Open 2

A SKC 2

C Buck 1

F Open 1

Pre-Cal Flowrate 198.6 200 200.7 201.2 200.8 198.5

Post-Cal Flowrate

200 199.1 199.6 199 200.1 199.2

Initial Stroke Count

Final Stroke Count

Time Sampled 83:50

Charcoal Tube # 1L 2L 3L 4L 5L 6L

PID Average Concentration: ____13.7 PPM___

Notes: Temperature: 73°F

Humidity: 22%

61

Experiment #_4S_

Date ____7/13/09____

Vapor: ___Hexane____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

D SKC 2

C Buck 1

B Open 2

E Buck 2

F SKC 1

A Open 1

Pre-Cal Flowrate 30.4 30 30.5 31.7 28.9 29.1

Post-Cal Flowrate 30.3 30.4 30.8 32.6 29 28.9

Initial Stroke Count

Final Stroke Count

Time Sampled 33:07

Charcoal Tube # 1S 2S 3S 4S 5S 6S

PID Average Concentration: ____13.1 PPM___

Notes: Temperature: 72°F

Humidity: 16%

62

Experiment #_4L_

Date ____7/13/09____

Vapor: ___Hexane____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

D SKC 2

C Buck 1

B Open 2

E Buck 2

F SKC 1

A Open 1

Pre-Cal Flowrate 30.3 30.4 30.8 32.6 29 28.9

Post-Cal Flowrate 30.1 29.9 30.7 33.3 28.7 28.6

Initial Stroke Count

Final Stroke Count

Time Sampled 84:00

Charcoal Tube # 1L 2L 3L 4L 5L 6L

PID Average Concentration: ___15.6 PPM____

Notes: Temperature: 73°F

Humidity: 17%

63

Experiment #__5__

Date ___7/14/09____

Vapor: ____Xylene____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

C Buck 1

B SKC 2

D Open 2

A Open 1

F SKC 1

E Buck 2

Pre-Cal Flowrate 30.8 31.8 28.6 29 32 29.4

Post-Cal Flowrate 29.6 31.3 28.1 28.2 31.9 29.1

Initial Stroke Count

Final Stroke Count

Time Sampled 81:05

Charcoal Tube # 1 2 3 4 5 6

PID Average Concentration: ___15.9 PPM___

Notes: Temperature: 75°F

Humidity: 15%

64

Experiment #__6__

Date ___7/14/09____

Vapor: ____Hexane____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

IA SKC 1

82 Buck 1

83 SKC 2

IM Buck 2

CA Open 2

CM Open 1

Pre-Cal Flowrate

201.4 201.4 201.4 200.8 197.5 201.7

Post-Cal Flowrate

197.9 199.4 200 200.9 197.6 199.6

Initial Stroke Count

69041 857021 637153 107052 807196 769923

Final Stroke Count

105091 893224 674477 141719 843858 806197

Time Sampled 81:02

Charcoal Tube #

1 2 3 4 5 6

PID Average Concentration: ____16.8 PPM___

Notes: Temperature: 72°F

Humidity: 16%

65

Experiment #__7__

Date ____7/15/09_____

Vapor: ____Hexane____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

B SKC 1

C Buck 1

E Buck 2

F Open 1

D Open 2

A SKC 2

Pre-Cal Flowrate 31.5 30.2 29.7 31.6 29.3 28.8

Post-Cal Flowrate 31.4 29.6 29.5 31.3 28.8 28.2

Initial Stroke Count

Final Stroke Count

Time Sampled 81:00

Charcoal Tube # 1 2 3 4 5 6

PID Average Concentration: ___16.1 PPM___

Notes: Temperature: 72°F

Humidity: 16%

66

Experiment #__8__

Date ___7/16/09____

Vapor: ____Xylene____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

82 Buck 2

83 Open 1

IM Buck 1

CA SKC 1

IA Open 2

CM SKC 2

Pre-Cal Flowrate

200.4 199.7 201.4 201.2 200.3 200.4

Post-Cal Flowrate

199.2 195.5 201 198.4 200.3 200.5

Initial Stroke Count

894377 676013 142747 845211 107261 808282

Final Stroke Count

930586 714374 177585 882956 144223 844842

Time Sampled 81:14

Charcoal Tube #

1 2 3 4 5 6

PID Average Concentration: ___15.5 PPM____

Notes: Temperature: 75°F

Humidity: 35%

67

Experiment #__9__

Date ____7/16/09_____

Vapor: ____Xylene____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

C Buck 1

F Open 1

D Open 2

B SKC 1

E Buck 2

A SKC 2

Pre-Cal Flowrate 200.4 198.5 199.8 201.1 200.2 200.6

Post-Cal Flowrate

200.2 201.5 199 202.1 199.9 198.7

Initial Stroke Count

Final Stroke Count

Time Sampled 81:15

Charcoal Tube # 1 2 3 4 5 6

PID Average Concentration: ___14.5 PPM____

Notes: Temperature: 73°F

Humidity: 18%

68

Experiment #_10S_

Date ___7/20/09____

Vapor: ____Xylene____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

IM Buck 2

CA SKC 2

CM SKC 1

82 Buck 1

IA Open 2

83 Open 1

Pre-Cal Flowrate 31.7 31.5 30.3 30.4 28.5 31.4

Post-Cal Flowrate 31.8 31.7 30.4 30.3 28.3 31.5

Initial Stroke Count

178085 883952 845358 931343 145151 715538

Final Stroke Count

180283 886229 847557 933447 147030 717706

Time Sampled 33:00

Charcoal Tube # 1S 2S 3S 4S 5S 6S

PID Average Concentration: ____16.3 PPM___

Notes: Temperature: 73°F

Humidity: 16%

69

Experiment #_10L_

Date ____7/20/09____

Vapor: ____Xylene____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

IM Buck 2

CA SKC 2

CM SKC 1

82 Buck 1

IA Open 2

83 Open 1

Pre-Cal Flowrate 31.8 31.7 30.4 30.3 28.3 32

Post-Cal Flowrate 31.9 31.9 30.2 30.3 28.4 31.8

Initial Stroke Count

180397 886354 847703 933614 147146 717957

Final Stroke Count

186014 892174 853290 938987 151926 723474

Time Sampled 84:00

Charcoal Tube # 1L 2L 3L 4L 5L 6L

PID Average Concentration: ___14.8 PPM___

Notes: Temperature: 73°F

Humidity: 16%

70

Experiment #_11S_

Date ____7/22/09____

Vapor: ____Xylene_____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

E Buck 2

D Open 1

B Open 2

F SKC 2

A SKC 1

C Buck 1

Pre-Cal Flowrate 198.9 200.9 199.8 200.2 199.3 198.1

Post-Cal Flowrate

197.9 198.6 201 198.1 197.1 197.4

Initial Stroke Count

Final Stroke Count

Time Sampled 33:00

Charcoal Tube # 1S 2S 3S 4S 5S 6S

PID Average Concentration: __12.0 PPM___

Notes: Temperature: 73°F

Humidity: 23%

71

Experiment #_11L_

Date ___7/22/09____

Vapor: ____Xylene____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

E Buck 2

D Open 1

B Open 2

F SKC 2

A SKC 1

C Buck 1

Pre-Cal Flowrate 201.1 200.4 201.1 199.7 200.4 199

Post-Cal Flowrate

196.3 200 199.9 198.6 198.3 187.4

Initial Stroke Count

Final Stroke Count

Time Sampled 84:55

Charcoal Tube # 1L 2L 3L 4L 5L 6L

PID Average Concentration: ___12.3 PPM____

Notes: Temperature: 71°F

Humidity: 25%

Pump C had a drop in flow rate of more than 5%

72

Experiment #_12S_

Date ___7/23/09___

Vapor: ___Xylene_____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

B Open 2

D SKC 1

C Buck 1

F Open 1

E Buck 2

A SKC 2

Pre-Cal Flowrate 28.1 32.3 29 28.9 30.3 31.1

Post-Cal Flowrate 28.3 32.5 28 28.6 29.4 30.5

Initial Stroke Count

Final Stroke Count

Time Sampled 33:00

Charcoal Tube # 1S 2S 3S 4S 5S 6S

PID Average Concentration: ___13.3 PPM___

Notes: Temperature: 72°F

Humidity: 23%

73

Experiment #_12L_

Date ____7/23/09____

Vapor: ____Xylene____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

B Open 2

D SKC 1

C Buck 1

F Open 1

E Buck 2

A SKC 2

Pre-Cal Flowrate 28.3 32.5 28.2 28.6 28.3 30.5

Post-Cal Flowrate 28.3 32.5 28.2 28.2 28.1 30.2

Initial Stroke Count

Final Stroke Count

Time Sampled 83:00

Charcoal Tube # 1L 2L 3L 4L 5L 6L

PID Average Concentration: ___14.8 PPM___

Notes: Temperature: 73°F

Humidity: 32%

74

Experiment #_13S_

Date ___7/27/09____

Vapor: ____Hexane____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

IA SKC 2

82 Buck 1

CA Open 2

83 SKC 1

CM Open 1

IM Buck 2

Pre-Cal Flowrate 30.9 30.3 28.7 30.6 29.3 29.8

Post-Cal Flowrate 31.6 31.2 28.9 31.4 29.1 30

Initial Stroke Count

152552 939314 892544 723824 990427 186439

Final Stroke Count

154770 941509 894596 726082 992719 188584

Time Sampled 34:00

Charcoal Tube # 1S 2S 3S 4S 5S 6S

PID Average Concentration: ___14.8 PPM___

Notes: Temperature: 70°F

Humidity: 24%

75

Experiment #_13L_

Date ___7/27/09____

Vapor: ____Hexane____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

IA SKC 2

82 Buck 1

CA Open 2

83 SKC 1

CM Open 1

IM Buck 2

Pre-Cal Flowrate 32 31.4 28.9 31.9 29.1 30

Post-Cal Flowrate

31.3 30.6 28.9 31.8 28.4 30.7

Initial Stroke Count

154877 941624 894661 726254 992833 188691

Final Stroke Count

160237 946940 899655 731758 998390 193900

Time Sampled 83:15

Charcoal Tube # 1L 2L 3L 4L 5L 6L

PID Average Concentration: ___12.8 PPM____

Notes: Temperature: 72°F

Humidity: 22%

76

Experiment #_14_

Date ____7/28/09____

Vapor: ____Hexane____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

E Buck 2

C Buck 1

B SKC 2

D Open 2

F SKC 1

A Open 1

Pre-Cal Flowrate 198.4 200.1 198.6 199.5 199.5 199.3

Post-Cal Flowrate

197 198.3 198.6 199.1 199 198

Initial Stroke Count

Final Stroke Count

Time Sampled 81:15

Charcoal Tube # 1 2 3 4 5 6

PID Average Concentration: __14.4 PPM___

Notes: Temperature: 73°F

Humidity: 22%

77

Experiment #_15S_

Date ____7/29/09____

Vapor: ____Xylene____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

IM Buck 2

CA Open 1

82 Buck 1

IA Open 2

CM SKC 2

83 SKC 1

Pre-Cal Flowrate 200.1 200.2 198 199.5 199.4 201.5

Post-Cal Flowrate

199.7 197.5 197.2 198.1 198.4 197.7

Initial Stroke Count

196167 900882 948176 161788 999038 733008

Final Stroke Count

210027 916636 962508 176894 1014317 749067

Time Sampled 33:15

Charcoal Tube # 1S 2S 3S 4S 5S 6S

PID Average Concentration: ___15.2 PPM____

Notes: Temperature: 73°F

Humidity: 32%

78

Experiment #_15L_

Date ___7/29/09___

Vapor: ____Xylene____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

IM Buck 2

CA Open 1

82 Buck 1

IA Open 2

CM SKC 2

83 SKC 1

Pre-Cal Flowrate 200.5 200.8 199.1 198.7 198 198.4

Post-Cal Flowrate

200.8 202 201.3 200.1 200.1 198

Initial Stroke Count

210796 917573 963464 177416 15074 750232

Final Stroke Count

246131 956808 1000086 215449 53529 789281

Time Sampled 83:30

Charcoal Tube # 1L 2L 3L 4L 5L 6L

PID Average Concentration: ___12.5 PPM___

Notes: Temperature: 73°F

Humidity: 31%

79

Experiment #_16S_

Date ___7/30/09___

Vapor: ____Hexane____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

83 SKC 2

82 Buck 2

CM SKC 1

IA Open 2

IM Buck 1

CA Open 1

Pre-Cal Flowrate

199 199.4 200.8 200 200.4 200.3

Post-Cal Flowrate

197.2 199.1 200.9 200.1 200.8 198.8

Initial Stroke Count

790590 962 54975 216883 246797 957563

Final Stroke Count

806819 15665 71002 232224 260960 973370

Time Sampled 33:15

Charcoal Tube # 1S 2S 3S 4S 5S 6S

PID Average Concentration: __12.0 PPM____

Notes: Temperature: 72°F

Humidity: 24%

80

Experiment #_16L_

Date ____7/30/09____

Vapor: ____Hexane____

Pump Type: Pulsating / Continuous

Exposure: Constant / Variable

Pump Flow Rate: Low / High

Mannequin: Yes / No

Sampling Time: Short / Long

Pump ID & Sample Holder

Type

83 SKC 2

82 Buck 2

CM SKC 1

IA Open 2

IM Buck 1

CA Open 1

Pre-Cal Flowrate 199 199 200.8 198.8 200.8 198.8

Post-Cal Flowrate 192.4 198.3 198.8 197.9 200.8 196.9

Initial Stroke Count

807462 15948 71750 232871 261429 973717

Final Stroke Count

846906 52728 111079 270994 296948 1012814

Time Sampled 83:30

Charcoal Tube # 1L 2L 3L 4L 5L 6L

PID Average Concentration: ___12.8 PPM___

Notes: Temperature: 72°F

Humidity: 24%

81

Table A1: Raw Data With Individual Sample Results and Sampler Positions on Mannequin or Stand

Run Conc.

(ppm) Vapor Pump Type

Exp.

Profile Flow Rate Mannequin Duration Holder Position

PID Conc.

(ppm) Temp. °F RH %

1 14.6 Hex Pulse Var Low No 83 Min SKC 1

16.0 70 17

1 14.1 Hex Pulse Var Low No 83 Min Buck 2

1 13.9 Hex Pulse Var Low No 83 Min Open 3

1 14.2 Hex Pulse Var Low No 83 Min SKC 4

1 14.0 Hex Pulse Var Low No 83 Min Open 5

1 13.5 Hex Pulse Var Low No 83 Min Buck 6

2 13.7 Xyl Pulse Var Low Yes 83 Min SKC 1

16.9 73 16

2 12.5 Xyl Pulse Var Low Yes 83 Min Open 2

2 14.8 Xyl Pulse Var Low Yes 83 Min Buck 3

2 13.5 Xyl Pulse Var Low Yes 83 Min Open 4

2 14.4 Xyl Pulse Var Low Yes 83 Min SKC 5

2 13.3 Xyl Pulse Var Low Yes 83 Min Buck 6

3S 11.1 Hex Cont Const High Yes 33 Min SKC 1

12.1 72 16

3S 11.4 Hex Cont Const High Yes 33 Min Buck 2

3S 10.6 Hex Cont Const High Yes 33 Min Open 3

3S 10.5 Hex Cont Const High Yes 33 Min SKC 4

3S 11.2 Hex Cont Const High Yes 33 Min Buck 5

3S 11.6 Hex Cont Const High Yes 33 Min Open 6

3L 13.7 Hex Cont Const High Yes 83 Min SKC 1

13.7 72 16

3L 14.2 Hex Cont Const High Yes 83 Min Buck 2

3L 14.2 Hex Cont Const High Yes 83 Min Open 3

3L 14.2 Hex Cont Const High Yes 83 Min SKC 4

3L 14.6 Hex Cont Const High Yes 83 Min Buck 5

3L 14.9 Hex Cont Const High Yes 83 Min Open 6

82

Table A1: Raw Data With Individual Sample Results and Sampler Positions on Mannequin or Stand (cont.)

Run Conc.

(ppm) Vapor Pump Type

Exp.

Profile Flow Rate Mannequin Duration Holder Position

PID Conc.

(ppm) Temp. °F RH %

4S 12.0 Hex Cont Const Low No 33 Min SKC 1

13.1 72 16

4S 13.8 Hex Cont Const Low No 33 Min Buck 2

4S 10.8 Hex Cont Const Low No 33 Min Open 3

4S 12.6 Hex Cont Const Low No 33 Min Buck 4

4S 10.5 Hex Cont Const Low No 33 Min SKC 5

4S 11.3 Hex Cont Const Low No 33 Min Open 6

4L 12.6 Hex Cont Const Low No 83 Min SKC 1

15.6 73 17

4L 14.5 Hex Cont Const Low No 83 Min Buck 2

4L 13.3 Hex Cont Const Low No 83 Min Open 3

4L 14.9 Hex Cont Const Low No 83 Min Buck 4

4L 12.6 Hex Cont Const Low No 83 Min SKC 5

4L 13.0 Hex Cont Const Low No 83 Min Open 6

5 15.4 Xyl Cont Var Low No 83 Min Buck 1

15.9 75 15

5 13.1 Xyl Cont Var Low No 83 Min SKC 2

5 13.2 Xyl Cont Var Low No 83 Min Open 3

5 13.3 Xyl Cont Var Low No 83 Min Open 4

5 13.4 Xyl Cont Var Low No 83 Min SKC 5

5 15.3 Xyl Cont Var Low No 83 Min Buck 6

6 14.2 Hex Pulse Var High Yes 83 Min SKC 1

16.8 72 16

6 14.2 Hex Pulse Var High Yes 83 Min Buck 2

6 14.1 Hex Pulse Var High Yes 83 Min SKC 3

6 14.3 Hex Pulse Var High Yes 83 Min Buck 4

6 14.3 Hex Pulse Var High Yes 83 Min Open 5

6 14.4 Hex Pulse Var High Yes 83 Min Open 6

83

Table A1: Raw Data With Individual Sample Results and Sampler Positions on Mannequin or Stand (cont.)

Run Conc.

(ppm) Vapor Pump Type

Exp.

Profile Flow Rate Mannequin Duration Holder Position

PID Conc.

(ppm) Temp. °F RH %

7 13.9 Hex Cont Var Low Yes 83 Min SKC 1

16.1 72 16

7 16.8 Hex Cont Var Low Yes 83 Min Buck 2

7 15.9 Hex Cont Var Low Yes 83 Min Buck 3

7 13.6 Hex Cont Var Low Yes 83 Min Open 4

7 13.5 Hex Cont Var Low Yes 83 Min Open 5

7 13.5 Hex Cont Var Low Yes 83 Min SKC 6

8 13.2 Xyl Pulse Var High No 83 Min Buck 1

15.5 75 35

8 13.2 Xyl Pulse Var High No 83 Min Open 2

8 12.9 Xyl Pulse Var High No 83 Min Buck 3

8 12.8 Xyl Pulse Var High No 83 Min SKC 4

8 13.6 Xyl Pulse Var High No 83 Min Open 5

8 13.2 Xyl Pulse Var High No 83 Min SKC 6

9 14.5 Xyl Cont Var High Yes 83 Min Buck 1

14.5 73 18

9 15.0 Xyl Cont Var High Yes 83 Min Open 2

9 14.3 Xyl Cont Var High Yes 83 Min Open 3

9 14.2 Xyl Cont Var High Yes 83 Min SKC 4

9 14.2 Xyl Cont Var High Yes 83 Min Buck 5

9 13.8 Xyl Cont Var High Yes 83 Min SKC 6

10S 15.1 Xyl Pulse Const Low No 33 Min Buck 1

16.3 73 16

10S 15.6 Xyl Pulse Const Low No 33 Min SKC 2

10S 15.2 Xyl Pulse Const Low No 33 Min SKC 3

10S 14.3 Xyl Pulse Const Low No 33 Min Buck 4

10S 15.3 Xyl Pulse Const Low No 33 Min Open 5

10S 15.6 Xyl Pulse Const Low No 33 Min Open 6

84

Table A1: Raw Data With Individual Sample Results and Sampler Positions on Mannequin or Stand (cont.)

Run Conc.

(ppm) Vapor Pump Type

Exp.

Profile Flow Rate Mannequin Duration Holder Position

PID Conc.

(ppm) Temp. °F RH %

10L 13.1 Xyl Pulse Const Low No 83 Min Buck 1

14.8 73 16

10L 13.5 Xyl Pulse Const Low No 83 Min SKC 2

10L 13.4 Xyl Pulse Const Low No 83 Min SKC 3

10L 13.0 Xyl Pulse Const Low No 83 Min Buck 4

10L 13.6 Xyl Pulse Const Low No 83 Min Open 5

10L 13.1 Xyl Pulse Const Low No 83 Min Open 6

11S 13.8 Xyl Cont Const High No 33 Min Buck 1

12.0 73 23

11S 14.3 Xyl Cont Const High No 33 Min Open 2

11S 13.4 Xyl Cont Const High No 33 Min Open 3

11S 13.3 Xyl Cont Const High No 33 Min SKC 4

11S 13.6 Xyl Cont Const High No 33 Min SKC 5

11S 14.2 Xyl Cont Const High No 33 Min Buck 6

11L 15.1 Xyl Cont Const High No 83 Min Buck 1

12.3 71 25

11L 14.8 Xyl Cont Const High No 83 Min Open 2

11L 14.8 Xyl Cont Const High No 83 Min Open 3

11L 13.6 Xyl Cont Const High No 83 Min SKC 4

11L 14.1 Xyl Cont Const High No 83 Min SKC 5

11L 14.5 Xyl Cont Const High No 83 Min Buck 6

12S 13.8 Xyl Cont Const Low Yes 33 Min Open 1

13.3 72 23

12S 13.6 Xyl Cont Const Low Yes 33 Min SKC 2

12S 14.5 Xyl Cont Const Low Yes 33 Min Buck 3

12S 14.1 Xyl Cont Const Low Yes 33 Min Open 4

12S 14.1 Xyl Cont Const Low Yes 33 Min Buck 5

12S 13.9 Xyl Cont Const Low Yes 33 Min SKC 6

85

Table A1: Raw Data With Individual Sample Results and Sampler Positions on Mannequin or Stand (cont.)

Run Conc.

(ppm) Vapor Pump Type

Exp.

Profile Flow Rate Mannequin Duration Holder Position

PID Conc.

(ppm) Temp. °F RH %

12L 16.6 Xyl Cont Const Low Yes 83 Min Open 1

14.8 73 32

12L 16.0 Xyl Cont Const Low Yes 83 Min SKC 2

12L 17.0 Xyl Cont Const Low Yes 83 Min Buck 3

12L 16.3 Xyl Cont Const Low Yes 83 Min Open 4

12L 16.5 Xyl Cont Const Low Yes 83 Min Buck 5

12L 16.3 Xyl Cont Const Low Yes 83 Min SKC 6

13S 9.2 Hex Pulse Const Low Yes 33 Min SKC 1

14.8 70 24

13S 9.0 Hex Pulse Const Low Yes 33 Min Buck 2

13S 9.5 Hex Pulse Const Low Yes 33 Min Open 3

13S 9.4 Hex Pulse Const Low Yes 33 Min SKC 4

13S 9.4 Hex Pulse Const Low Yes 33 Min Open 5

13S 9.4 Hex Pulse Const Low Yes 33 Min Buck 6

13L 11.7 Hex Pulse Const Low Yes 83 Min SKC 1

12.8 72 22

13L 11.4 Hex Pulse Const Low Yes 83 Min Buck 2

13L 12.1 Hex Pulse Const Low Yes 83 Min Open 3

13L 12.0 Hex Pulse Const Low Yes 83 Min SKC 4

13L 12.6 Hex Pulse Const Low Yes 83 Min Open 5

13L 12.0 Hex Pulse Const Low Yes 83 Min Buck 6

14 15.2 Hex Pulse Var High No 83 Min Buck 1

14.4 73 22

14 15.0 Hex Pulse Var High No 83 Min Buck 2

14 14.6 Hex Pulse Var High No 83 Min SKC 3

14 15.3 Hex Pulse Var High No 83 Min Open 4

14 15.3 Hex Pulse Var High No 83 Min SKC 5

14 15.7 Hex Pulse Var High No 83 Min Open 6

86

Table A1: Raw Data With Individual Sample Results and Sampler Positions on Mannequin or Stand (cont.)

Run Conc.

(ppm) Vapor Pump Type

Exp.

Profile Flow Rate Mannequin Duration Holder Position

PID Conc.

(ppm) Temp. °F RH %

15S 12.4 Xyl Pulse Const High Yes 33 Min Buck 1

15.2 73 32

15S 12.4 Xyl Pulse Const High Yes 33 Min Open 2

15S 12.8 Xyl Pulse Const High Yes 33 Min Buck 3

15S 13.0 Xyl Pulse Const High Yes 33 Min Open 4

15S 13.1 Xyl Pulse Const High Yes 33 Min SKC 5

15S 12.9 Xyl Pulse Const High Yes 33 Min SKC 6

15L 14.2 Xyl Pulse Const High Yes 83 Min Buck 1

12.5 73 31

15L 14.2 Xyl Pulse Const High Yes 83 Min Open 2

15L 14.0 Xyl Pulse Const High Yes 83 Min Buck 3

15L 14.2 Xyl Pulse Const High Yes 83 Min Open 4

15L 14.2 Xyl Pulse Const High Yes 83 Min SKC 5

15L 13.7 Xyl Pulse Const High Yes 83 Min SKC 6

16S 10.9 Hex Pulse Const High No 33 Min SKC 1

12.0 72 24

16S 11.4 Hex Pulse Const High No 33 Min Buck 2

16S 11.3 Hex Pulse Const High No 33 Min SKC 3

16S 11.1 Hex Pulse Const High No 33 Min Open 4

16S 11.3 Hex Pulse Const High No 33 Min Buck 5

16S 11.3 Hex Pulse Const High No 33 Min Open 6

16L 13.4 Hex Pulse Const High No 83 Min SKC 1

12.8 72 24

16L 13.6 Hex Pulse Const High No 83 Min Buck 2

16L 13.4 Hex Pulse Const High No 83 Min SKC 3

16L 13.7 Hex Pulse Const High No 83 Min Open 4

16L 13.7 Hex Pulse Const High No 83 Min Buck 5

16L 13.4 Hex Pulse Const High No 83 Min Open 6

87

Table A2: Run Table With Results For Concentration Ratio Run Vapor Pump

Type Exp. Prof. Flow Rate Mannequin Holder Duration Conc.

Ratio

1 Hex Pulse Var Low No SKC Long 1.03

2 Xyl Pulse Var Low Yes SKC Long 1.08

3 Hex Cont. Con High Yes SKC Short 0.97

4 Hex Cont. Con High Yes SKC Long 0.96

5 Hex Cont. Con Low No SKC Short 1.02

6 Hex Cont. Con Low No SKC Long 0.96

7 Xyl Cont. Var Low No SKC Long 1.00

8 Hex Pulse Var High Yes SKC Long 0.99

9 Hex Cont. Var Low Yes SKC Long 1.01

10 Xyl Pulse Var High No SKC Long 0.97

11 Xyl Cont. Var High Yes SKC Long 0.96

12 Xyl Pulse Con Low No SKC Short 1.00

13 Xyl Pulse Con Low No SKC Long 1.01

14 Xyl Cont. Con High No SKC Short 0.97

15 Xyl Cont. Con High No SKC Long 0.94

16 Xyl Cont. Con Low Yes SKC Short 0.99

17 Xyl Cont. Con Low Yes SKC Long 0.98

18 Hex Pulse Con Low Yes SKC Short 0.98

19 Hex Pulse Con Low Yes SKC Long 0.96

20 Hex Cont. Var High No SKC Long 0.96

21 Xyl Pulse Con High Yes SKC Short 1.02

22 Xyl Pulse Con High Yes SKC Long 0.98

23 Hex Pulse Con High No SKC Short 0.99

24 Hex Pulse Con High No SKC Long 0.99

1 Hex Pulse Var Low No Buck Long 0.99

2 Xyl Pulse Var Low Yes Buck Long 1.08

3 Hex Cont. Con High Yes Buck Short 1.02

4 Hex Cont. Con High Yes Buck Long 0.99

5 Hex Cont. Con Low No Buck Short 1.19

6 Hex Cont. Con Low No Buck Long 1.12

7 Xyl Cont. Var Low No Buck Long 1.16

8 Hex Pulse Var High Yes Buck Long 0.99

9 Hex Cont. Var Low Yes Buck Long 1.21

10 Xyl Pulse Var High No Buck Long 0.97

11 Xyl Cont. Var High Yes Buck Long 0.98

12 Xyl Pulse Con Low No Buck Short 0.95

13 Xyl Pulse Con Low No Buck Long 0.98

14 Xyl Cont. Con High No Buck Short 1.01

15 Xyl Cont. Con High No Buck Long 1.00

16 Xyl Cont. Con Low Yes Buck Short 1.03

17 Xyl Cont. Con Low Yes Buck Long 1.02

18 Hex Pulse Con Low Yes Buck Short 0.97

19 Hex Pulse Con Low Yes Buck Long 0.95

20 Hex Cont. Var High No Buck Long 0.97

21 Xyl Pulse Con High Yes Buck Short 0.99

22 Xyl Pulse Con High Yes Buck Long 0.99

23 Hex Pulse Con High No Buck Short 1.01

24 Hex Pulse Con High No Buck Long 1.01