national air toxics trends sites data characterization ... · national air toxics trends sites data...

National Air Toxics Trends Sites Data Characterization,

2004-2007Regi Oommen

Eastern Research Group, Inc (ERG)

1600 Perimeter Park

Morrisville, NC 27560

November 4, 2009

National Air Monitoring Conference – Nashville, TN

Acknowledgements• U.S. EPA

• Barbara Driscoll, Work Assignment Manager• Mike Jones

• ERG• Jaime Hauser• Julie Swift• Heather Perez• Karla Faught

• RTI –

Jennifer Lloyd• Work funded under U.S. EPA Contract EP-D-08-047


• Dave Dayton• Steve Mendenhall• Kerry Fountain• Jody Tisano

Oommen – pg 2

Overview of Presentation

• NATTS Overview

• Data Set

• Results

• Data Quality Challenges

• Next Steps

National Air Monitoring Conference – Nashville, TN Oommen – pg 3

NATTS•

Created to obtain long-term ambient air toxics concentration

data at specific fixed sites across the country

• Purpose: • Validating modeling results and emission inventories (NATA)

• Assessing current regulatory benchmarks

•

Establishing policies for reducing the risk of developing cancerous and noncancerous health effects

•

Evaluate two 3-year period averages for comparison (2004-06 and 2007-09)

• Used recently to help assess School Air Toxics data studyNational Air Monitoring Conference – Nashville, TN Oommen – pg 4

NATTS Sites• This presentation covers data from sites from 2004-2007


= Rural Site

2004-06: 23 sites2007: 25 sites2008: 28 sites

Oommen – pg 5

NATTS Sites (all)


Site Code AQS Code Location Site Code AQS Code Location

BOMA 25-025-0042 Boston, MA PLORb 41-051-0246 Portland, OR

BTUT 49-011-0004 Bountiful, UT PRRI 44-007-0022 Providence, RI

BXNY 36-005-0110 Bronx, NY PXSS 04-013-9997 Phoenix, AZ

CAMS 35 48-201-1039 Deer Park, TX RIVAb 51-087-0014 Richmond, VA

CAMS 85 48-203-0002 Karnack, TX ROCH 36-055-1007 Rochester, NY

CELAa 06-037-1103 Los Angeles, CA RUCAa 06-065-8001 Rubidoux, CA

CHSC 45-025-0001 Chesterfield, SC S4MO 29-510-0085 St. Louis, MO

DEMI 26-163-0033 Dearborn, MI SDGA 13-089-0002 Atlanta, GA

GLKYb 21-043-0500 Grayson Lake, KY SEWA 53-033-0080 Seattle, WA

GPCO 08-077-0017/18 Grand Junction, CO SJCA 06-085-0005 San Jose, CA

HAKYc 21-193-0003 Hazard, KY SKFL 12-103-0026 Pinellas Park, FL

LAOR 41-061-0119 La Grande, OR SYFL 12-057-3002 Tampa, FL

MVWI 55-027-0007 Mayville, WI UNVT 50-007-0007 Underhill, VT

NBIL 17-031-4201 Northbrook, IL WADC 11-001-0043 Washington, D.C.

a: Added 2007b: Added 2008c: Discontinued 2008

Oommen – pg 6

NATTS Pollutants• Pollutant Groups:

• VOCs

(TO-15)• Carbonyls (TO-11A)• Metals, PM10

(IO-3.5)• Hexavalent

Chromium (EPA-Approved)

• PAHs

(TO-13)

• PAHs

began sampling in 2007 (not included in this presentation)

• Hexavalent

Chromium began sampling in 2005

• Report focuses on HAPs

only


NATTS MQO HAPs• Method Quality Objective (MQO) HAPs

• Acetaldehyde• Acrolein• Arsenic• Benzene• Benzo(a)Pyrene• Beryllium• 1,3-Butadiene• Cadmium• Carbon Tetrachloride• Chloroform

• Naphthalene and benzo(a)pyrene

not included in this assessment


• Formaldehyde• Hexavalent

Chromium

• Lead• Manganase• Naphthalene• Nickel• Tetrachloroethylene• Trichloethylene• Vinyl Chloride

Oommen – pg 8

Data Retrieval• Phase VI Data Archive:

• Consisted of data from 1973-2007 from AQS, IMPROVE, etc.

• Large HAP archive of 26 million records

• NATTS sites are required to submit data into AQS

• Over 262,000 data records retrieved

• State-level files are posted at:http://www.epa.gov/ttn/amtic/toxdat.html


Question 1 –

What was the data completeness for the network?

• 342 possible data sets for 2004-2007:• VOCs: 23 sites * 4 years = 92 data sets• Carbonyls: 23 sites * 4 years = 92 data sets• Metals: 23 sites * 4 years = 92 data sets• Hex Chrome: 22 sites * 3 years = 66 data sets

• 35 data sets did not meet 85% sampling criteria• NATTS Contract Laboratory: 4 data sets• Independent Laboratories: 31 data sets

• 28 expected data sets were not found in AQS

• 8 data sets “invalidated”

due to suspiciously high values


Data Completeness -

Overall


VOCs Carbonyls Metals Hex Chrome

Period A B C A B C A B C A B C

2004 1,158 1,273 91 1,026 1,167 88 771 819 94 NA NA NA

2005 1,263 1,354 93 1,113 1,251 89 981 1,022 96 874 915 96

2006 1,262 1,329 95 1,096 1,269 86 1,069 1,106 97 983 1,023 96

2007 1,092 1,172 93 1,168 1,372 85 1,134 1,202 94 1,099 1,155 95

Overall 4,775 5,128 93 4,403 5,059 87 3,955 4,149 95 2,956 3,093 96

A = Number of Valid SamplesB = Total Number of SamplesC = Percentage Completeness

Oommen – pg 11

# Data Sets > 85% completeness


Invalidated Data Sets by Site


Three of twenty-three sites had a data set that was not used in this analysis; a

total of 8 data sets were not used for this analysis.

Oommen – pg 13

Missing Data Sets by Site


Ten of twenty-three sites had an expected data set that was not found in AQS; a total of 28 data sets were not found.

Oommen – pg 14

Question 2 –

What HAPs

were detected most?


Detections -

Top 20 HAPs


Detections –

Middle 16 HAPs


Detections –

Bottom 20 HAPs


Question 3 –

As a network, what were the central tendencies and data distributions of the HAP data?


HAP Detectsa Averageb

(µg/m3)Minimum(µg/m3)

25th(µg/m3)

50th

(µg/m3)75th

(µg/m3)Maximum

(µg/m3)

Formaldehyde 4,741 3.15 ±

0.10 0.01 1.34 2.33 3.97 91.50

Acetaldehyde 4,733 1.94 ±

0.07 0.01 0.88 1.44 2.36 92.78

Benzene 4,482 1.13 ±

0.03 0.01 0.54 0.86 1.39 10.19

Toluene 4,221 2.71 ±

0.25 0.01 0.83 1.66 3.26 482.53

Xylene, m/p- 4,175 1.29 ±

0.05 0.02 0.39 0.78 1.56 21.41

Carbon Tetrachloride 4,060 0.59 ±

0.01 0.03 0.50 0.57 0.66 1.53

Chloromethane 4,059 1.21 ±

0.01 0.03 1.04 1.18 1.34 19.70

a: minimum 4,000 detectsb: includes confidence interval at alpha = 0.05

Oommen – pg 19

Question 4 –

How do the NATTS measurements compare to short-, intermediate-, and long-term health benchmarks?


• EPA’s Risk Screening Approach

• ATSDR’s

Minimal Risk Levels (MRLs)

• Cancer/Noncancer

Risk Approximations

Oommen – pg 20

Risk Evaluation –

Risk Screening


• Risk Screening Approach •

EPA has published a guidance document outlining a risk

screening approach that utilizes a risk-based methodology to perform an initial screen of ambient air toxics monitoring data sets.

•

This screening process provides a risk-based methodology for analysts and interested parties to identify which pollutants may pose a health risk in their area.

• Not all NATTS pollutants have screening values.

• m/p-Xylene

and o-Xylene

were summed together

Oommen – pg 21

Risk Evaluation –

Risk Screening


Pollutant# of Failed

Screens

# ofMeasuredDetections

% ofFailed Screens

% of Total

Failures

Acetaldehyde 4,461 4,733 94.25% 11.09%

Benzene 4,421 4,482 98.64% 10.99%

Carbon Tetrachloride 4,056 4,060 99.90% 10.08%

Formaldehyde 3,977 4,741 83.89% 9.88%

Chromium Compounds 3,423 3,493 98.00% 8.51%

Arsenic Compounds 3,133 3,365 93.11% 7.79%

Butadiene, 1,3- 2,852 3,282 86.90% 7.09%

Tetrachloroethylene 1,894 3,401 55.69% 4.71%

Manganese Compounds 1,769 3,684 48.02% 4.40%

Dichlorobenzene, p- 1,678 2,436 68.88% 4.17%

Acrolein 1,470 1,471 99.93% 3.65%

Nickel Compounds 1,374 3,397 40.45% 3.41%

41 Other HAPs 5,729 71,019 8.07% 14.24%

TOTAL 40,237 113,564 35.43% NA

Oommen – pg 22

Risk Evaluation –

Risk Screening


• Summary • Twelve HAPs

contributed to the Top 85% of all failed screens

• Thirteen HAPs

did not fail any screens

• Ten HAPs

failed >90% of their screens:• Acetaldehyde• Benzene• Carbon Tetrachloride• Chromium compounds• Arsenic compounds

• Acrolein• 1,1,2,2-Tetrachloroethane• Ethylene Dibromide• Acrylonitrile• α-Chlorotoluene

Oommen – pg 23

Risk Evaluation –

MRLs


• Minimal Risk Levels (MRLs)•

An MRL is a concentration of a hazardous substance that

is “without appreciable risk of adverse noncancer health effects over a specified duration of exposure”

• MRLs

are intended to be used as screening tools

• ATSDR defines MRLs

for three durations of exposure:• acute (1 to 14 days)• intermediate (15 to 364 days)• chronic exposure (1 year or greater).

• Short-term MRL compared to 24-hour measurement

Oommen – pg 24

Risk Evaluation –

MRLs


• Intermediate MRL comparison: comparison with the Seasonal Average

• Seasonal Average: “Subseason

Zone”

Approach• e.g. Spring (March 21-June 20)

• Subseason

Zone 1: March 21-March 31• Subseason

Zone 2: April 1-April 12

• Subseason

Zone 3: April 13-April 24• Subseason

Zone 4: April 25-May 6

• Subseason

Zone 5: May 7-May 18• Subseason

Zone 6: May 19-May 30

• Subseason

Zone 7: May 31-June 11• Subseason

Zone 8: June 12-June 20

•

Must have at least 1 detect within six of eight zones to be valid; used NATTS background concentrations or ½

MDL for missing zones

Oommen – pg 25

Risk Evaluation –

non-Chronic


Pollutant

Acute Risk Intermediate Risk

ATSDR MRL

(µg/m3)# of

Exceedances

ATSDR MRL

(µg/m3)

# of Winter

Exceedances

# of Spring

Exceedances

# of Summer

Exceedances

# of Autumn

Exceedances

Formaldehyde 50 3/4,741 40 0/80 0/84 0/85 0/84

Acrolein 7 1/1,471 0.09 23/24 25/26 27/27 30/31

Exceedances

of the MRL

Oommen – pg 26

Risk Evaluation –

Chronic MRLs


• Chronic MRL comparison: comparison with the Annual Average

• Annual Average: average of at least 3 Seasonal Averages to be valid.

• No

annual averages were higher than its chronic MRL.

•

Sites that did not have enough acrolein

detects to calculate an Annual Average include: BXNY, CAMS 35, CHSC, HAKY, LAOR, MVWI, ROCH, SDGA, UNVT, and WADC.

Oommen – pg 27

Risk Evaluation –

Cancer Risk Approximations


•

Cancer risk is defined as the likelihood of developing cancer as a result of exposure over a 70-year period.

•

Presented as the number of people at risk for cancer per million people

•

Cancer risk approximations for 28 HAPs

were calculated in the following manner:

Cancer Risk Approximation = Annual Average * Cancer URE * 10E-6

• Nearly 45% of the Cancer Risk Approximations were ≤

1 in-a-million

Oommen – pg 28

Acetaldehyde Cancer Risk Approximations


Benzene Cancer Risk Approximations


Carbon Tetrachloride Cancer Risk Approximations


Ethylene Dibromide

Cancer Risk Approximations


Nickel Cancer Risk Approximations


Cumulative Cancer Risk Approximations


Risk Evaluation –

Noncancer

Risk Approximations


• Noncancer

risk is presented as the Noncancer

Hazard Quotient (HQ).

•

Noncancer

health effects target certain areas, such as respiratory, neurological, kidneys, and liver systems.

•

If the HQ is calculated to be less than 1.0, then no adverse health effects are expected as a result of exposure, if the HQ is greater than 1.0 the adverse health effects are possible.

•

Noncancer

risk approximations for 10 target areas were calculated in the following manner:

Noncancer

Risk HQ Approximation = Annual Average ÷

Noncancer

RfC

÷

1000

Oommen – pg 35

Neurological Noncancer

Risk Approximations


Reproductive Noncancer

Risk Approximations


Respiratory Noncancer

Risk Approximations


Question 5 –

What were the 3-year period averages?


• 3-Yr Period Average:• Average of annual averages• Need to have 2 annual averages to be valid• Could only be conducted for 2004-2006 timeframe• Conducted for only the MQO HAPs• Compared to the 2007 average for preliminary assessment

•

Results: Over 75% of the comparisons realized a decrease in period average concentrations (not statistically significant)

•

Problem: Potential of nearly 400 period averages…only 200 were calculated.

Oommen – pg 39

Question 6 –

How can the results of this assessment be improved?


• Challenges with NATTS Data:• Parameter Occurrence Codes: multiple to choose from

• Missing pollutant group data sets

• Questionable data were invalidated

• Under-reporting of pollutants

• MDL Reporting

• MDL Ranges

Oommen – pg 40


2004 HAKY = 1,283.62005 HAKY = 1,542.5

0.0

5.0

10.0

15.0

20.0

25.0

BO

MA

BTU

T

BX

NY

CA

MS

35

CA

MS

85

CH

SC

DEM

I

GPC

O

HA

KY

LAO

R

MV

WI

NB

IL

PRR

I

PXSS

RO

CH

S4M

O

SDG

A

SEW

A

SJC

A

SKFL

SYFL

UN

VT

WA

DC

Can

cer

Ris

k A

ppro

xim

atio

n (in

-a-m

illio

n)

2004200520062007

0.0

1.0

2.0

3.0

4.0

5.0

BO

MA

BTU

T

BX

NY

CA

MS

35

CA

MS

85

CH

SC

DEM

I

GPC

O

HA

KY

LAO

R

MV

WI

NB

IL

PRR

I

PXSS

RO

CH

S4M

O

SDG

A

SEW

A

SJC

A

SKFL

SYFL

UN

VT

WA

DC

Can

cer

Ris

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ppro

xim

atio

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-a-m

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Questionable Data -

Examples

1,1,2-Trichloroethane cancer risk at LAOR: >4 in-a-million

Ethylene dibromide

cancer risk at HAKY: >1200 in-a-million

Oommen – pg 41

Under-reporting of Specific HAPs

Example


Benzene Detects by Site

Acrolein

Detects by Site

Oommen – pg 42

Number of HAPs

by Site


Under-reporting of Multiple HAPs

Example

Oommen – pg 43


MDL Reporting/Ranges• MDL Reporting:

•

Over 42% of the Independent Laboratories MDL values used in this analysis report were not populated in AQS.

• NATTS Contract Laboratory: 100%

• Selected MDL Ranges

Pollutant Units Minimum MDL

Maximum MDL

Average MDL

Average Federal MDL

Acrolein µg/m3 0.002 5.81 0.212 0.079

Benzene µg/m3 0.011 1.597 0.132 0.087

Methylene

Chloride µg/m3 0.035 17.368 0.637 0.322

Acetaldehyde ng/m3 0.004 1.333 0.220 0.221

Arsenic ng/m3 0.003 22 6.834 7.461

Manganese ng/m3 0.004 1.2 0.358 0.295

Nickel ng/m3 0.009 4 0.95 0.814

Oommen – pg 44


Next Steps• September 30, 2009 –

Draft 2004-2007 Assessment sent to EPA

• November 4, 2009 –

Report can be e-mailed to states/EPA-regional offices.

•

November 4, 2009 to December 31, 2009 –

Comments due/Opportunity for new/corrected data to be uploaded into AQS.

• December 2009 –

Quarterly NATTS conference call

• January 2, 2010 –

AQS data pull for NATTS data

• February 28, 2010 –

Finalize 2004-2007 Assessment

• August 2010 –

AQS data pull for 2008 and 2009 NATTS data

•

October 2010 –

Draft 2004-2009 Assessment completed; NATTS Network Assessment

Oommen – pg 45


Questions/Comments?Regi

OommenEastern Research Group, Inc.

Morrisville, NC919-468-7829

[email protected]

Barbara DriscollU.S. EPARTP, NC

[email protected]

Mike JonesU.S. EPARTP, NC

[email protected]

Oommen – pg 46

mailto:[email protected]



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