Indoor Air Quality

Building a new home provides the opportunity for preventing indoor air problems. However, it can result in exposure to higher levels of indoor air contaminants if careful attention is not given to potential pollution sources and the air exchange rate.

Express your concerns about indoor air quality to your architect or builder and enlist his or her cooperation in taking measures to provide good indoor air quality. Talk both about purchasing building materials and furnishings that are low-emitting and about providing an adequate amount of ventilation.

The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) recommends a ventilation rate of 0.35 ach (air changes per hour) for new homes, and some new homes are built to even tighter specifications. Particular care should be given in such homes to preventing the build-up of indoor air pollutants to high levels.

Radon | Asbestos | Lead | Biologicals | Carbon Monoxide | Organic Gas | Pesticides | Respirable Particles | Formaldehyde | Additional Resources

Construction Tips:

Use radon-resistant construction techniques.
Obtain a copy of the EPA booklet, Model Standards and Techniques for Control of Radon in New Residential Buildings, from your state radon office or health agency, your state homebuilders' association, or your EPA regional office. [You can also visit EPA's Radon Resistant New Construction (RRNC)].
Choose building materials and furnishings that will keep indoor air pollution to a minimum.
There are many actions a homeowner can take to select products that will prevent indoor air problems from occurring - a couple of them are mentioned here. First, use exterior-grade pressed wood products made with phenol-formaldehyde resin in floors, cabinetry, and wall surfaces. Or, as an alternative, consider using solid wood products. Secondly, if you plan to install wall-to-wall carpet on concrete in contact with the ground, especially concrete in basements, make sure that an effective moisture barrier is installed prior to installing the carpet. Do not permanently adhere carpet to concrete with adhesives so that the carpet can be removed if it becomes wet.

Provide proper drainage and seal foundations in new construction.
Air that enters the home through the foundation can contain more moisture than is generated from all occupant activities.
Become familiar with mechanical ventilation systems and consider installing one.
Advanced designs of new homes are starting to feature mechanical systems that bring outdoor air into the home. Some of these designs include energy-efficient heat recovery ventilators (also known as air-to-air heat exchangers).
Ensure that combustion appliances, including furnaces, fireplaces, woodstoves, and heaters, are properly vented and receive enough supply air.
Combustion gases, including carbon monoxide, and particles can be back-drafted from the chimney or flue into the living space if the combustion appliance is not properly vented or does not receive enough supply air. Back-drafting can be a particular problem in weatherized or tightly constructed homes. Installing a dedicated outdoor air supply for the combustion appliance can help prevent backdrafting.

Reference Guide to Major Indoor Air Pollutants in the Home
The pollutants listed in this guide have been shown to cause the health effects mentioned. However, it is not necessarily true that the effects noted occur at the pollutant concentration levels typically found in the home. In many cases, our understanding of the pollutants and their health effects is too limited to determine the levels at which the listed effects could occur.

RADON (Rn)
Sources: Earth and rock beneath home; well water; building materials.

Health Effects: No immediate symptoms. Estimated to contribute to between 7,000 and 30,000 lung cancer deaths each year. Smokers are at higher risk of developing radon-induced lung cancer.

Levels in Homes: Based on a national residential radon survey completed in 1991, the average indoor radon level is 1.3 picocuries per liter (pCi/L). The average outdoor level is about 0.4 pCi/L.

Steps to Reduce Exposure:

Test your home for radon_it's easy and inexpensive.
Fix your home if your radon level is 4 picocuries per liter (pCi/L) or higher.
Radon levels less than 4 pCi/L still pose a risk, and in many cases may be reduced.
If you want more information on radon, contact your state radon office, or call 800-SOS-RADON.
ENVIRONMENTAL TOBACCO SMOKE (ETS)
Source: Cigarette, pipe, and cigar smoking.

Health Effects: Eye, nose, and throat irritation; headaches; lung cancer; may contribute to heart disease. Specifically for children, increased risk of lower respiratory tract infections, such as bronchitis and pneumonia, and ear infections; build-up of fluid in the middle ear; increased severity and frequency of asthma episodes; decreased lung function.

Levels in Homes: Particle levels in homes without smokers or other strong particle sources are the same as, or lower than, those outdoors. Homes with one or more smokers may have particle levels several times higher than outdoor levels.

Steps to Reduce Exposure:

Do not smoke in your home or permit others to do so.
Do not smoke if children are present, particularly infants and toddlers.
If smoking indoors cannot be avoided, increase ventilation in the area where smoking takes place. Open windows or use exhaust fans.

BIOLOGICALS
Sources: Wet or moist walls, ceilings, carpets, and furniture; poorly maintained humidifiers, dehumidifiers, and air conditioners; bedding; household pets.

Health Effects: Eye, nose, and throat irritation; shortness of breath; dizziness; lethargy; fever; digestive problems. Can cause asthma; humidifier fever; influenza and other infectious diseases.

Levels in Homes: Indoor levels of pollen and fungi are lower than outdoor levels (except where indoor sources of fungi are present). Indoor levels of dust mites are higher than outdoor levels.

Steps to Reduce Exposure:

Install and use fans vented to outdoors in kitchens and bathrooms.
Vent clothes dryers to outdoors.
Clean cool mist and ultrasonic humidifiers in accordance with manufacturer's instructions and refill with clean water daily.
Empty water trays in air conditioners, dehumidifiers, and refrigerators frequently.
Clean and dry or remove water-damaged carpets.
Use basements as living areas only if they are leak-proof and have adequate ventilation. Use dehumidifiers, if necessary, to maintain humidity between 30-50 percent.

CARBON MONOXIDE (CO)
Sources: Unvented kerosene and gas space heaters; leaking chimneys and furnaces; back-drafting from furnaces, gas water heaters, woodstoves, and fireplaces; gas stoves. Automobile exhaust from attached garages. Environmental Tobacco Smoke.

Health Effects: At low concentrations, fatigue in healthy people and chest pain in people with heart disease. At higher concentrations, impaired vision and coordination; headaches; dizziness; confusion; nausea. Can cause flu-like symptoms that clear up after leaving home. Fatal at very high concentrations.

Levels in Homes: Average levels in homes without gas stoves vary from 0.5 to 5 parts per million (ppm). Levels near properly adjusted gas stoves are often 5 to 15 ppm and those near poorly adjusted stoves may be 30 ppm or higher.

Steps to Reduce Exposure:

Keep gas appliances properly adjusted.
Consider purchasing a vented space heater when replacing an unvented one.
Use proper fuel in kerosene space heaters.
Install and use an exhaust fan vented to outdoors over gas stoves.
Open flues when fireplaces are in use.
Choose properly sized woodstoves that are certified to meet EPA emission standards. Make certain that doors on all woodstoves fit tightly.
Have a trained professional inspect, clean, and tune-up central heating system (furnaces, flues, and chimneys) annually. Repair any leaks promptly.
Do not idle the car inside garage.

NITROGEN DIOXIDE (NO2)
Sources: Kerosene heaters, unvented gas stoves and heaters. Environmental tobacco smoke. Health Effects: Eye, nose, and throat irritation. May cause impaired lung function and increased respiratory infections in young children.

Levels in Homes: Average level in homes without combustion appliances is about half that of outdoors. In homes with gas stoves, kerosene heaters, or unvented gas space heaters, indoor levels often exceed outdoor levels.

Steps to Reduce Exposure: See steps under carbon monoxide.

ORGANIC GASES
Sources: Household products including: paints, paint strippers, and other solvents; wood preservatives; aerosol sprays; cleansers and disinfectants; moth repellents and air fresheners; stored fuels and automotive products; hobby supplies; dry-cleaned clothing.

Health Effects: Eye, nose, and throat irritation; headaches, loss of coordination, nausea; damage to liver, kidney, and central nervous system. Some organics can cause cancer in animals; some are suspected or known to cause cancer in humans.

Levels in Homes: Studies have found that levels of several organics average 2 to 5 times higher indoors than outdoors. During and for several hours immediately after certain activities, such as paint stripping, levels may be 1,000 times background outdoor levels.

Steps to Reduce Exposure:

Use household products according to manufacturer's directions.
Make sure you provide plenty of fresh air when using these products.
Throw away unused or little-used containers safely; buy in quantities that you will use soon.
Keep out of reach of children and pets.
Never mix household care products unless directed on the label.

RESPIRABLE PARTICLES
Sources: Fireplaces, woodstoves, and kerosene heaters. Environmental tobacco smoke.

Health Effects: Eye, nose, and throat irritation; respiratory infections and bronchitis; lung cancer. (Effects attributable to environmental tobacco smoke are listed elsewhere.)

Levels in Homes: Particle levels in homes without smoking or other strong particle sources are the same as, or lower than, outdoor levels.

Steps to Reduce Exposure:

Vent all furnaces to outdoors; keep doors to rest of house open when using unvented space heaters.
Choose properly sized woodstoves, certified to meet EPA emission standards; make certain that doors on all woodstoves fit tightly.
Have a trained professional inspect, clean, and tune-up central heating system (furnace, flues, and chimneys) annually. Repair any leaks promptly.
Change filters on central heating and cooling systems and air cleaners according to manufacturer's directions.

FORMALDEHYDE
Sources: Pressed wood products (hardwood plywood wall paneling, particleboard, fiberboard) and furniture made with these pressed wood products. Urea-formaldehyde foam insulation (UFFI). Combustion sources and environmental tobacco smoke. Durable press drapes, other textiles, and glues.

Health Effects: Eye, nose, and throat irritation; wheezing and coughing; fatigue; skin rash; severe allergic reactions. May cause cancer. May also cause other effects listed under "organic gases."

Levels in Homes: Average concentrations in older homes without UFFI are generally well below 0.1 (ppm). In homes with significant amounts of new pressed wood products, levels can be greater than 0.3 ppm.

Steps to Reduce Exposure:

Use "exterior-grade" pressed wood products (lower-emitting because they contain phenol resins, not urea resins).
Use air conditioning and dehumidifiers to maintain moderate temperature and reduce humidity levels.
Increase ventilation, particularly after bringing new sources of formaldehyde into the home.

PESTICIDES
Sources: Products used to kill household pests (insecticides, termiticides, and disinfectants). Also, products used on lawns and gardens that drift or are tracked inside the house.

Health Effects: Irritation to eye, nose, and throat; damage to central nervous system and kidney; increased risk of cancer.

Levels in Homes: Preliminary research shows widespread presence of pesticide residues in homes.

Steps to Reduce Exposure:

Use strictly according to manufacturer's directions.
Mix or dilute outdoors.
Apply only in recommended quantities.
Increase ventilation when using indoors. Take plants or pets outdoors when applying pesticides to them.
Use non-chemical methods of pest control where possible.
If you use a pest control company, select it carefully.
Do not store unneeded pesticides inside home; dispose of unwanted containers safely.
Store clothes with moth repellents in separately ventilated areas, if possible.
Keep indoor spaces clean, dry, and well ventilated to avoid pest and odor problems.

ASBESTOS
Sources: Deteriorating, damaged, or disturbed insulation, fireproofing, acoustical materials, and floor tiles.

Health Effects: No immediate symptoms, but long-term risk of chest and abdominal cancers and lung diseases. Smokers are at higher risk of developing asbestos-induced lung cancer.

Levels in Homes: Elevated levels can occur in homes where asbestos-containing materials are damaged or disturbed.

Steps to Reduce Exposure:

It is best to leave undamaged asbestos material alone if it is not likely to be disturbed.
Use trained and qualified contractors for control measures that may disturb asbestos and for cleanup.
Follow proper procedures in replacing woodstove door gaskets that may contain asbestos.

LEAD
Sources: Lead-based paint, contaminated soil, dust, and drinking water.

Health Effects: Lead affects practically all systems within the body. Lead at high levels (lead levels at or above 80 micrograms per deciliter (80 ug/dl) of blood) can cause convulsions, coma, and even death. Lower levels of lead can cause adverse health effects on the central nervous system, kidney, and blood cells. Blood lead levels as low as 10 ug/dl can impair mental and physical development.

Steps to Reduce Exposure:

Keep areas where children play as dust-free and clean as possible.
Leave lead-based paint undisturbed if it is in good condition; do not sand or burn off paint that may contain lead.
Do not remove lead paint yourself.
Do not bring lead dust into the home.
If your work or hobby involves lead, change clothes and use doormats before entering your home.
Eat a balanced diet, rich in calcium and iron.

DISCLAIMER: Links to other Federal Agencies on this page (designated with ) are pointers to other hosts and locations in the Internet. The information on this is provided here as a service. The U.S. Environmental Protection Agency does not endorse, approve or otherwise support these other Federal sites.

Federal Information Sources for Indoor Air Quality
Federal agencies with indoor air quality information may be contacted as follows:U. S. Environmental Protection Agency (U.S. EPA)

INDOOR AIR QUALITY - Information Clearinghouse (IAQ INFO)
P.O. Box 37133
Washington, DC 20013-7133
(800) 438-4318; (703) 356-4020
(fax) 703-356-5386 or e-mail: iaqinfo@aol.com
Operates Monday to Friday from 9a.m. to 5p.m. Eastern Standard Time (EST). Distributes EPA publications, answers questions on the phone, and makes referrals to other nonprofit and governmental organizations.

NATIONAL RADON HOTLINES
(800) SOS-RADON
[(800) 767-7236]
Information recording operates 24 hours a day.

NATIONAL LEAD INFORMATION CENTER
(800) LEAD-FYI
[(800) 532-3394]
Operates 24 hours a day, seven days a week. Callers may order an information package. To speak to an information specialist, call (800) 424-5323. Operates Monday to Friday from 8:30a.m. to 5p.m. EST.

NATIONAL PESTICIDES TELECOMMUNICATIONS NETWORK
National toll-free number: (800) 858-PEST
[In Oregon - (800) 858-7378]
Operates Monday to Friday from 6:30a.m. to 4:30p.m. Pacific Time. Provides information about pesticides to the general public and the medical, veterinary, and professional communities. Medical and government personnel may call 800-858-7377.

SAFE DRINKING WATER HOTLINE
(800) 426-4791
Operates Monday to Friday from 8:30a.m. to 5p.m. EST. Provides information on regulations under the Safe Drinking Water Act, lead and radon in drinking water, filter information, and a list of state drinking water offices.

TSCA ASSISTANCE INFORMATION SERVICE
(202) 554-1404
Operates Monday to Friday from 8:30a.m. to 5p.m. EST. Provides information on regulations under the Toxic Substances Control Act and on EPA's asbestos program.

U.S. Consumer Product Safety Commission (CPSC) [http://www.cpsc.gov/]

Washington, DC 20207-0001
Product Safety Hotline: (800) 638-CPSC
Teletypewriter for the hearing impaired (outside Maryland): (800) 638-8270;
Maryland only: (800) 492-8104.
Recorded information is available 24 hours a day when calling from a touch-tone phone. Operators are on duty Monday to Friday from 10:30 to 4 EST to take complaints about unsafe consumer products.

U.S. Department of Housing and Urban Development [http://www.hud.gov/]

Office of Energy and the Environment, Washington, DC 20410
HUD USER National toll-free number: (800) 245-2691
In Washington, DC area: (301) 251-5154

U.S. Department of Energy [http://www.doe.gov/]

Office of Conservation and Renewable Energy
1000 Independence Ave., SW, Washington, DC 20585

Conservation and Renewable Energy Inquiry and Referral Service (CAREIRS)
PO Box 3048, Merrifield, VA 22116
Operates Monday to Friday from 9 to 5 EST. Provides consumer information on conservation and renewable energy in residences.

U.S. Public Health Service

Division of Federal Occupational Health
Office of Environmental Hygiene, Region III, Room 1310
3535 Market St., Philadelphia, PA 19104
(215) 596-1888; fax: 215-596-5024
Provides indoor air quality consultative services to federal agency managers.

Centers for Disease Control and Prevention [http://www.cdc.gov]

Lead Poisoning Prevention Branch
Centers for Disease Control and Prevention
4770 Buford Highway, NE (F-42)
Atlanta, GA 30341-3724
(800) 488-7330

State and Local Organizations
Your questions or concerns about indoor air problems can frequently be answered by the government agencies in your state or local government. Responsibilities for indoor air quality issues are usually divided among many different agencies. Calling or writing the agencies responsible for health or air quality control is the best way to start getting information from your state or local government. To obtain state agency contacts, write or call EPA's IAQ Information Clearinghouse, (800) 438-4318, (703) 356-4020 in the Washington, D.C. area.

Other Organizations
The following organizations have information specifically discussed in this booklet. Call the IAQ Information Clearinghouse at (800) 438-4318 for the names of a variety of organizations that have more information on specific and general indoor air quality issues.

American Association of Poison Control Centers (AAPCC)
3800 Reservoir Road, NW
Washington, DC 20007

Association of Home Appliance Manufacturers (AHAM)
1111 19th Street, NW
Suite 402
Washington, DC 20036
(202) 872-5955

AHAM also provides information on air cleaners on their AHAM-certified Clean Air Delivery Rate site at www.cadr.org

American Society of Heating, Refrigerating, and Air-Conditioning (ASHRAE)
1791 Tullie Circle NE
Atlanta, GA 30329

World Health Organization (WHO)
Publications Center
49 Sheridan Avenue
Albany, NY 12210

Your Local American Lung Association (ALA)
National ALA Headquarters
1740 Broadway
New York, NY 10019
(800) LUNG-USA

Glossary of Terms

ACID AEROSOL: Acidic liquid or solid particles that are small enough to become airborne. High concentrations of acid aerosols can be irritating to the lungs and have been associated with some respiratory diseases, such as asthma.

ANIMAL DANDER: Tiny scales of animal skin.

ALLERGEN: A substance capable of causing an allergic reaction because of an individual's sensitivity to that substance.

ALLERGIC RHINITIS: Inflammation of the mucous membranes in the nose that is caused by an allergic reaction.

BUILDING-RELATED ILLNESS: A discrete, identifiable disease or illness that can be traced to a specific pollutant or source within a building. (Contrast with "Sick building syndrome").

CHEMICAL SENSITIZATION: Evidence suggests that some people may develop health problems characterized by effects such as dizziness, eye and throat irritation, chest tightness, and nasal congestion that appear whenever they are exposed to certain chemicals. People may react to even trace amounts of chemicals to which they have become "sensitized."

ENVIRONMENTAL TOBACCO SMOKE (ETS): Mixture of smoke from the burning end of a cigarette, pipe, or cigar and smoke exhaled by the smoker (also secondhand smoke or passive smoking).

FUNGI: Any of a group of parasitic lower plants that lack chlorophyll, including molds and mildews.

HUMIDIFIER FEVER: A respiratory illness caused by exposure to toxins from microorganisms found in wet or moist areas in humidifiers and air conditioners. Also called air conditioner or ventilation fever.

HYPERSENSITIVITY PNEUMONITIS: A group of respiratory diseases that cause inflammation of the lung (specifically granulomatous cells). Most forms of hypersensitivity pneumonitis are caused by the inhalation of organic dusts, including molds.

ORGANIC COMPOUNDS: Chemicals that contain carbon. Volatile organic compounds vaporize at room temperature and pressure. They are found in many indoor sources, including many common household products and building materials.

PICOCURIE (pCi): A unit for measuring radioactivity, often expressed as picocuries per liter (pCi/L) of air.

PRESSED WOOD PRODUCTS: A group of materials used in building and furniture construction that are made from wood veneers, particles, or fibers bonded together with an adhesive under heat and pressure.

RADON (Rn) AND RADON DECAY PRODUCTS: Radon is a radioactive gas formed in the decay of uranium. The radon decay products (also called radon daughters or progeny) can be breathed into the lung where they continue to release radiation as they further decay.

SICK BUILDING SYNDROME: Term that refers to a set of symptoms that affect some number of building occupants during the time they spend in the building and diminish or go away during periods when they leave the building. Cannot be traced to specific pollutants or sources within the building. (Contrast with "Building related illness").

VENTILATION RATE: The rate at which indoor air enters and leaves a building. Expressed in one of two ways: the number of changes of outdoor air per unit of time (air changes per hour, or "ach") or the rate at which a volume of outdoor air enters per unit of time (cubic feet per minute, or "cfm").

How Do I Order a Copy of This Booklet?
This document is in the public domain. It may be reproduced in part or in whole by an individual or organization without permission. Single copies of this booklet are available from:

EPA's IAQ Information Clearinghouse (IAQINFO)
(800) 438-4318; (703) 356-4020
P.O. Box 37133,
Washington, DC, 20013-7133
iaqinfo@aol.com

or, you can order these publications directly via EPA's National Service Center for Environmental Publications (NSCEP) (http://www.epa.gov/ncepihom/). web site. Your publication requests can also be mailed, called or faxed directly to:

U.S. Environmental Protection Agency
National Center for Environmental Publications (NSCEP)
P.O. Box 42419
Cincinnati, OH 42419
1-800-490-9198/(513) 489-8695 (fax)

Please use the EPA Document Number (# 402-K-93-007, April 1995), when ordering from NSCEP or from IAQ INFO.

Multiple copies may be purchased from the Government Printing Office. Call (202) 783-3238 or send check or money order for $44.00 (25 per package) to: Superintendent of Documents, P.O. Box 371954, Pittsburgh, PA, 15250-7954. Include the stock number 055-000-00441-2.

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