Source Control

Usually the most effective way to improve indoor air quality is to eliminate individual sources of pollution or to reduce their emissions. Some sources, like those that contain asbestos, can be sealed or enclosed; others, like gas stoves, can be adjusted to decrease the amount of emissions. 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. Specific sources of indoor air pollution in your home are listed later in this section.

Ventilation Improvements

Another approach to lowering the concentrations of indoor air pollutants in your home is to increase the amount of outdoor air coming indoors. Most home heating and cooling systems, including forced air heating systems, do not mechanically bring fresh air into the house. 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. Local bathroom or kitchen fans that exhaust outdoors remove contaminants directly from the room where the fan is located and also increase the outdoor air ventilation rate.

It is particularly 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 for example, painting, paint stripping, heating with kerosene heaters, cooking, or engaging in maintenance and hobby activities such as welding, soldering, or sanding. You might also choose to do some of these activities outdoors, if you can and if weather permits.

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). For more information about air-to-air heat exchangers, contact the Conservation and Renewable Energy Inquiry and Referral Service (CAREIRS), PO Box 3048, Merrifield, VA 22116; (800) 5232929.

Air Cleaners

There are many types and sizes of air cleaners on the market, ranging from relatively inexpensive tabletop models to sophisticated and expensive whole house systems. Some air cleaners are highly effective at particle removal, while others, including most tabletop models, are much less so. Air cleaners are generally not designed to remove gaseous pollutants.

The effectiveness of an air cleaner depends on how well it collects pollutants from indoor air (expressed as a percentage efficiency rate) and how much air it draws through the cleaning or filtering element (expressed in cubic feet per minute). 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. Tabletop air cleaners, in particular, may not remove satisfactory amounts of pollutants from strong nearby sources. People with a sensitivity to particular sources may find that air cleaners are helpful only in conjunction with concerted efforts to remove the source.

Over the past few years, there has been some publicity suggesting that house plants have been shown to reduce levels of some chemicals in laboratory experiments. There is currently no evidence, however, that a reasonable number of houseplants remove significant quantities of pollutants in homes and offices. Indoor houseplants should not be over watered because overly damp soil may promote the growth of microorganisms which can affect allergic individuals.

At present, EPA does not recommend using air cleaners to reduce levels of radon and its decay products. The effectiveness of these devices is uncertain because they only partially remove the radon decay products and do not diminish the amount of radon entering the home. EPA plans to do additional research on whether air cleaners are, or could become, a reliable means of reducing the health risk from radon. EPA s booklet, Residential Air Cleaning Devices, provides further information on air cleaning devices to reduce indoor air pollutants

For most indoor air quality problems in the home, source control is the most effective solution. This section takes a source by source look at the most common indoor air pollutants, their potential health effects, and ways to reduce levels in the home. (For a summary of the points made in this section, see the chart in the middle of this booklet titled Reference Guide to Major Indoor Air Pollutants in the Home. )

RADON

The most common source of indoor radon is uranium in the soil or rock on which homes are built. As uranium naturally breaks down, it releases radon gas which is a colorless, odorless, radioactive gas. Radon gas enters homes through dirt floors, cracks in concrete walls and floors, floor drains, and sumps. When radon become strapped in buildings and concentrations build up indoors, exposure to radon becomes a concern.

Any home may have a radon problem. This means new and old homes, well sealed and drafty homes, and homes with or without basements.

Sometimes radon enters the home through well water. In a small number of homes, the building materials can give off radon, too. However, building materials rarely cause radon problems by themselves.

Health Effects of Radon

The predominant health effect associated with exposure to elevated levels of radon is lung cancer. Research suggests that swallowing water with high radon levels may pose risks, too, although these are believed to be much lower than those from breathing air containing radon. Major health organizations (like the Centers for Disease Control and Prevention, the American Lung Association (ALA), and the American Medical Association) agree with estimates that radon causes thousands of preventable lung cancer deaths each year. EPA estimates that radon causes about 14,000 deaths per year in the United States however, this number could range from 7,000 to 30,000 deaths per year. If you smoke and your home has high radon levels, your risk of lung cancer is especially high.

Reducing Exposure to Radon in Homes

Measure levels of radon in your home.

You can t see radon, but it s not hard to find out if you have a radon problem in your home. Testing is easy and should only take a little of your time.

There are many kinds of inexpensive, do-it-yourself radon test kits you can get through the mail and in hardware stores and other retail outlets. Make sure you buy a test kit that has passed EPA s testing program or is state certified. These kits will usually display the phrase Meets EPA Requirements. If you prefer, or if you are buying or selling a home, you can hire a trained contractor to do the testing for you. The EPA Radon Measurement Proficiency (RMP) Program evaluates testing contractors. A contractor who has met EPA s requirements will carry a special RMP identification card. EPA provides a list of companies and individual contractors to state radon offices. You can call your state radon office to obtain a list of qualified contractors in your area (call 800-SOS-RADON for a list of state radon offices).

Refer to the EPA guidelines on how to test and interpret your test results.

You can learn more about radon through EPA s publications, A Citizen s Guide to Radon: The Guide to Protecting Yourself and Your Family From Radon and Home Buyer s and Seller s Guide to Radon, which are available from state radon offices.

Learn about radon reduction methods.

Ways to reduce radon in your home are discussed in EPA s Consumer s Guide to Radon Reduction. You can get a copy from your state radon office. There are simple solutions to radon problems in homes. Thousands of homeowners have already fixed radon problems. Lowering high radon levels requires technical knowledge and special skills. You should use a contractor who is trained to fix radon problems.

The EPA Radon Contractor Proficiency (RCP) Program tests these contractors. EPA provides a list of RCP contractors to state radon offices. A contractor who is listed by EPA will carry a special RCP identification card. A trained RCP contractor can study the problem in your home and help you pick the correct treatment method. Check with your state radon office for names of qualified or state certified radon reduction contractors in your area.

Stop smoking and discourage smoking in your home.

Scientific evidence indicates that smoking combined with radon is an especially serious health risk. Stop smoking and lower your radon level to reduce lung cancer risk.

Treat radon contaminated well water.

While radon in water is not a problem in homes served by most public water supplies, it has been found in well water. If you've tested the air in your home and found a radon problem, and you have a well, contact a lab certified to measure radiation in water to have your water tested. Radon problems in water can be readily fixed. Call your state radon office or the EPA Drinking Water Hotline (8004264791) for more information.

ENVIRONMENTAL TOBACCO SMOKE

Environmental tobacco smoke (ETS) is the mixture of smoke that comes from the burning end of a cigarette, pipe, or cigar, and smoke exhaled by the smoker. It is a complex mixture of over 4,000 compounds, more than 40 of which are known to cause cancer in humans or animals and many of which are strong irritants. ETS is often referred to as secondhand smoke and exposure to ETS is often called passive smoking.

Health Effects of Environmental Tobacco Smoke

In 1992, EPA completed a major assessment of the respiratory health risks of ETS (Respiratory Health Effects of Passive Smoking: Lung Cancer and Other Disorders EPA/600/690/006F). The report concludes that exposure to ETS is responsible for approximately 3,000 lung cancer deaths each year in non-smoking adults and impairs the respiratory health of hundreds of thousands of children.

Infants and young children whose parents smoke in their presence are at increased risk of lower respiratory tract infections (pneumonia and bronchitis) and are more likely to have symptoms of respiratory irritation like cough, excess phlegm, and wheeze. EPA estimates that passive smoking annually causes between 150,000 and 300,000 lower respiratory tract infections in infants and children under 18 months of age, resulting in between 7,500 and 15,000 hospitalizations each year. These children may also have a buildup of fluid in the middle ear, which can lead to ear infections. Older children who have been exposed to secondhand smoke may have slightly reduced lung function.

Asthmatic children are especially at risk. EPA estimates that exposure to secondhand smoke increases the number of episodes and severity of symptoms in hundreds of thousands of asthmatic children, and may cause thousands of non-asthmatic children to develop the disease each year. EPA estimates that between 200,000 and 1,000,000 asthmatic children have their condition made worse by exposure to secondhand smoke each year.

Exposure to secondhand smoke causes eye, nose, and throat irritation. It may affect the cardiovascular system and some studies have linked exposure to secondhand smoke with the onset of chest pain. For publications about ETS, contact EPA s Indoor Air Quality Information Clearinghouse (IAQ-INFO), 8004384318.

Reducing Exposure to Environmental Tobacco Smoke

Don t smoke at home or permit others to do so. Ask smokers to smoke outdoors.

The 1986 Surgeon General s report concluded that physical separation of smokers and nonsmokers in a common air space, such as different rooms within the same house, may reduce but will not eliminate nonsmokers exposure to environmental tobacco smoke.

If smoking indoors cannot be avoided, increase ventilation in the area where smoking takes place.

Open windows or use exhaust fans. Ventilation, a common method of reducing exposure to indoor air pollutants, also will reduce but not eliminate exposure to environmental tobacco smoke. Because smoking produces such large amounts of pollutants, natural or mechanical ventilation techniques do not remove them from the air in your home as quickly as they build up. In addition, the large increases in ventilation it takes to significantly reduce exposure to environmental tobacco smoke can also increase energy costs substantially. Consequently, the most effective way to reduce exposure to environmental tobacco smoke in the home is to eliminate smoking there.

Do not smoke if children are present, particularly infants and toddlers.

Children are particularly susceptible to the effects of passive smoking. Do not allow baby sitters or others who work in your home to smoke indoors. Discourage others from smoking around children. Find out about the smoking policies of the day care center providers, schools, and other care givers for your children. The policy should protect children from exposure to ETS.

CONTINUED IN  A GUIDE TO INDOOR AIR QUALITY Part 3