Indoor Air Pollution

Sara Lance

Kim Kubera

Arsineh Hecobian

Rick Peltier

Introduction and Summary

Sources of Indoor Air Pollutants

Transportation/Movement

Unique Chemistry

Specific Health Effects

Indoor Air Pollution - Overview

People spend most of their time indoors.

The EPA has shown that indoor levels of some pollutants, such as formaldehyde, chloroform, and styrene, range from 2 to 50 times higher than outdoor levels.

Exposure to pollutants such as environmental tobacco smoke and radon occurs almost entirely indoors.

Indoor Air Pollution

Main Categories:1) toxic gases

e.g. carbon monoxide, ozone, formaldehyde

2) particulate matter e.g. candles, incense, smoke, pet dander

3) radiogenic species e.g. Radon-220, Polonium-210

4) biological organismse.g. mold, dust mites, bacteria

Some Specific Indoor Air Pollutants

Acetone - in cosmetics, fragrances, human breath Ammonia - in cleaning products Benzene - in laser printers, particle board, paint, tobacco Benzaldehyde - in detergents and fragrances Benzyl acetate - in air fresheners, fragrances Chloroform - in chlorinated tap water Formaldehyde - in particle boards, carpets, clothes, glue Limonene - in deodorants, disinfectants, fragrances Terpinen - in deodorants, fragrances Toulene - in glue, laser printers, paint and particle board Trichloroethyl - in photocopiers Xylene - in glue, laser printers, paint and particle board

Laser printers Photocopiers Fax machines

Ozone Generators touted as “Air Cleaning” devices

Indoor Sources of Ozone

EPA’s Stance on Ozone Generators

ozone generators are not effective at removing many of the most harmful chemicals--including carbon monoxide and formaldehyde--commonly found in indoor environments.

for many of the chemicals with which ozone does readily react, ozone forms a variety of harmful or irritating by-products, including aldehydes and other organic chemicals.

ozone does not remove particles (such as dust and pollen) from the air.

Coverage - up to 2,000 square feet Maximum Ozone Output - 750 mg/hr

Ozone Generator - http://www.purennatural.com

The “Ozone Zapper”- According to Specs

With “perfect mixing”, the maximum output rate (750 mg/hr) combined with the maximum area coverage (2,000 ft2) gives an ozone production rate of 920 ppb/hr.

Ozone concentrations will be greater near the “Ozone Zapper” source.

920 ppb O3 is more than 10 times the EPA’s eight-hour standard.

Lead Particulates - Candle Burning

The core of candle wicks may contain lead. Out of the molten wax, lead can be emitted as

particulate to the air. In an EPA study, of 100 sets of candles that

appeared to have metal-core wicks, 8% contained lead wicks.

Environmental Tobacco Smoke (ETS)

The EPA has classified environmental tobacco smoke as a class A carcinogen, responsible for approximately 3,000 lung cancer deaths and 62,000 heart disease deaths annually in U.S. non-smokers.

ETS includes toxic gases, particulate matter and radiogenic species.

Among the powerful poisons in Environmental Tobacco Smoke (ETS) are:

Carbon monoxide Nitrogen oxide Ammonia Methyl isocyanate Hydrogen cyanide Phenol Among the carcinogens in ETS are: Benzo [a] pyrene Nitrosamines Aromatic amines Benzene Formaldehyde Polonium-210 (radioactive)

Tobacco Toxins

Radon

A colorless, odorless, invisible radioactive gas, is released into the air from the uranium found naturally in rocks and soil.

Radon Entry Points – US EPA

Radon Exposure – EPA Guidelines

EPA Standard for Radon = 4 pCi/L

Out of 1,000 people exposed to 4 pCi/L over a lifetime, 2 non-smokers and 29 smokers are predicted to get lung cancer.

Smoking and radon gas exposure show a synergistic relationship with respect to lung cancer.

Estimated Fraction of Homes with Long-term, Living-Area Average Radon Concentrations over 4 pCi/L

Legionnaires’ Disease

“A bacterial disease commonly associated with water-based aerosols and often a result of poorly maintained air conditioning cooling towers and potable water systems.” (OSHA)

Cases have been reported in the US, Australia, Netherlands, UK…

Dust Mites

These microscopic insects excrete proteins that can trigger asthma and allergy attacks in people.

“Typical places to find mites are the mattress, and the carpeting next to the bed, because the bed is where we spend the majority of our time -- at least 8 hours a day sleeping, so we lose a lot of skin cells there,” said Glass. “The average person sheds enough skin cells every day to feed thousands of mites for a month.”

Indoor Pollution Transport

Indoor to Outdoor, Outdoor to Indoor Transport (basic methods/terminology)

How do you improve indoor air pollution

Basic Transportation

Infiltration

- flows into the house through openings, joints, and cracks in walls, floors, and ceilings, and around windows and doors.

Natural ventilation - air moves through opened

windows and doors.

(Air movement associated with infiltration and natural ventilation is caused by air temperature differences between indoors and outdoors and by wind.)

Transport - Continued

Mechanical ventilation - 1.outdoor-vented fans that

intermittently remove air from a single room

- 2. air handling systems that use fans and duct work to continuously remove indoor air and distribute filtered and conditioned outdoor air to strategic points throughout the house.

The rate at which outdoor air replaces indoor air is described as the air exchange rate. When there is little infiltration, natural ventilation, or mechanical ventilation, the air exchange rate is low and pollutant levels can increase.

Source Control

eliminate individual sources of pollution or to reduce their emissions.

- seal or enclose (asbestos) - adjust to decrease the amount of

emissions. (gas stoves) In many cases, source control is also a more

cost-efficient approach to protecting indoor air quality than increasing ventilation because increasing ventilation can increase energy costs.

Ventilation Improvements

increase the amount of outdoor air coming indoors.

- Opening windows and doors, operating window or attic fans, when the weather permits, or running a window air conditioner with the vent control open increases the outdoor ventilation rate.

Ventilation - Continued

important to take as many of these steps as possible while you are involved in short-term activities that can generate high levels of pollutants.

- painting, paint stripping, heating with kerosene heaters, cooking, or engaging in maintenance and hobby activities such as welding, soldering, or sanding.

Air Cleaners

many types and sizes of air cleaners on the market

- ranging from relatively inexpensive table-top models to sophisticated and expensive whole-house systems.

Some are highly effective at particle removal, while others, including most table-top models, are much less so.

Air cleaners are generally not designed to remove gaseous pollutants.

Air Cleaners - Continued

The effectiveness of an air cleaner depends on how well it collects pollutants from indoor air and how much air it draws through the cleaning or filtering element.

A very efficient collector with a low air-circulation rate will not be effective, nor will a cleaner with a high air-circulation rate but a less efficient collector.

The long-term performance of any air cleaner depends on maintaining it according to the manufacturer's directions.

Another important factor in determining the effectiveness of an air cleaner is the strength of the pollutant source.

Table-top air cleaners may not remove satisfactory amounts of pollutants from strong nearby sources.

Indoor Chemical Pollutants

Sources (physical and chemical)

Sinks (physical and chemical)

Reactions (chemical sources and sinks)

Some Chemical Air Pollutants

Sulfur DioxideCarbon MonoxideNitrogen DioxideParticulate MatterOzone

Some Volatile Organic CompoundsCompound Health Effects

Benzene Carcinogen; respiratory tract irritant

Xylenes Narcotic; irritant; affects heart, liver, kidney, and nervous system

Toluene Narcotic; possible cause of anemia

Styrene Narcotic; affects control of nervous system; probable human carcinogen

Toluene diisocyanate (TDI) Sensitizer; probable human carcinogen

Trichlaroethane Affects central nervous system

Ethyl benzene Severe irritation of eyes and respiratory tract; affects central nervous system

Dichloromethane Narcotic; affects nervous system; probable human carcinogen

1.4-Dichlorobenzene Narcotic; affect liver, kidney, and central nervous system; eye and respiratory tract irritant

Benzyl chloride Central nervous system depressant; affects liver and kidney; eye and respiratory tract irritant

2-Butanone (MEK) Irritant; central nervous system depressant

Petroleum distillates Affects central nervous system, liver, and kidneys

4-Phenylcyclohexene Eye and respiratory tract irritant; central nervous system

Source: U.S. Environmental Protection Agency (EPA). Introduction to Indoor Air Quality. Report no. EPA/400/3–91/ 003, Washington, DC: U.S. Environmental Protection Agency, 1991.

Reaction between -pinene and O3

Source: The significance of secondary organic aerosol formation and growth in buildings: experimental and computational evidence Golam Sarwar, Richard Corsi, David Allen and Charles Weschler

What Chemicals are IMPORTANT?

Free Radicals (OH)

Oxidizers (O3)

NOx

SourcesTransportCombustion Processes

Range: Indoor: 20-50 ppbOutdoor: 10-500 ppt (Ludwig et al, 1974)

O3+NO NO2+O2

The importance of NOx

O3+NO2 NO3+O2

NO3+RH HNO3+Ro

OH Radical

Outdoor to indoor transport

Reactions with VOC

Calculated rate constants for removal of hydroxyl radical

Source: Free radical chemistry and its concern with indoor air quality: an open problem, Giovanni Ingrosso

Source:Indoor Chemistry: Ozone and Volatile Organic Compounds Found in Tobacco Smoke Richard J. Shaughnessy, T. J. McDaniels, and Charles J. Weschler

Tobacco Smoke: Inert Chemicals

Source:Indoor Chemistry: Ozone and Volatile Organic Compounds Found in Tobacco Smoke Richard J. Shaughnessy, T. J. McDaniels, and Charles J. Weschler

Tobacco Smoke: Reactive Chemicals

Source:Indoor Chemistry: Ozone and Volatile Organic Compounds Found in Tobacco Smoke Richard J. Shaughnessy, T. J. McDaniels, and Charles J. Weschler

Chemicals Produced From Ozone Reactions

Surface Deposition

More surface areasDifferent types of surfacesRelative Humidity

The Bigger Picture: Impacts on Humanity

Americans spend majority of their day in an indoor environment.

Other cultures can spend more/less time indoors

Health Effects - Respiratory

Physiology affords a uniquely reactive environment

Direct pathways to internal systems

Although low in tidal volume, high in

frequency (69000 liter/day = 6900 m3/day

(= 13.2 kilogram at PM10 standard of 75g over

lifetime)

Health Effects - Cardiac

Peters et al. – strong correlation between ST segment elevation and PM2.5 mass.

Acid deposition (gas and particle) and linkage to cardiac ischemia???

Biogenic Air Pollutants

Chew et al. – Cockroach allergen and sensitivity to Asthma

Consistent 8-10 hour exposure to Epidermal detritus

Pet dander

Adequacy of Monitoring

Debatable whether or not EPA monitors reflect magnitude of exposures – monitors generally deployed near industrial facilities to monitor compliance.

Personal monitors currently best way to measure exposure (although far from perfect – “personal cloud”)

The Comforts of Home

Tolerance for ETS

Pesticide/herbicide application

Cooking

“workshop” products

A Special Health Concern:

Children Curiosity Developing High

metabolism Ground-level

activity

Non-Health Effects

Stress decreased job performance, missed time at work/school, etc.

Oxidants decaying possessions (i.e. artwork, food products)

Summary and Conclusions

SourcesHeterogeneous, numerous, etc.

TransportNot uniform throughout homes, critical to

understanding chemistry

ChemistryBoth oxidizing and reducing environments, wider

array of chemical species

EffectsHealth and other effects widespread, largely due

to “comforts of home”.

BibliographyBurge, H. Bioaerosols: Prevalence and Health Effects in the Indoor Environment. J Allergy and Clin Immunology: 86:5, 687-702, 1990.

Clean Air Amendments of 1970, Public Law 91–604, 84 Statute, December 31,1970. Air Standards Authorization implemented by U.S. Environmental Protection Agency, Washington, DC, April 30, 1971.

Chew G; Stelmach I; Jerzynska J; Stelmach W; Majak P; Gorski P; Kuna Cockroach allergy and exposure to cockroach allergen in Polish children with Asthma. Allergy, 2002 Aug, 57(8):701-5

Munir, A., Kjellman, M., Bjorksten, B. Exposure to Indoor Allergens in Early Infancy and Senstization. J Allergy and Clin Immunology. 100:2, 177-181, 1997.

Peters, A., D. Dockery, et al. (2001). "Increased Particulate Air Pollution and the Triggering of Myocardial Infarction." Circulation 103: 2810-2815.

Ritchie, Ingrid.; Martin, Stephen John. The Healthy Home Kit : Inspecting for Environmental Hazards, Working With Professionals to Avoid Risks, Cleaning Up Radon, Lead, Asbestos, and More!

U.S. Environmental Protection Agency (EPA). Introduction to Indoor Air Quality. Report no. EPA/400/3–91/ 003, Washington, DC: U.S. Environmental Protection Agency, 1991.

U.S. Environmental Protection Agency, Indoor Air Pollution: An Introduction for Health Professionals, No. 1994-523-217/81322, 1994