Air May Be Much Dirtier Inside Than Out


Indoor air pollution can be just as bad as or even worse than outdoor air pollution.

Studies by the Environmental Protection Agency of human exposure to air pollutants indicate that indoor air levels of many pollutants may be two to five times, and occasionally more than 100 times, higher than outdoor levels. It’s estimated that most people spend as much as 90% of their time indoors--making home, school and the workplace potentially hazardous to one’s health.

Further, laws designed to improve energy efficiency by cutting down on drafts don’t improve indoor air quality. Tightly sealed homes constructed in the last couple of decades might have diminished the use of fossil fuels, but have wreaked havoc with Americans’ respiratory systems. Homes that can’t “breathe” can’t dilute pollutants contained in building and decorating products.

Indoor pollution sources that release gases or particles into the air are the primary cause of indoor air-quality problems. Inadequate ventilation can increase indoor pollutant levels by not bringing in enough outdoor air to dilute emissions from indoor sources, and by not carrying indoor air pollutants out of the home. This allows concentrations to build up. All these pollutants have one thing in common: They contain chemicals that are part of a larger class of chemicals known as volatile organic compounds or VOCs. VOCs are organic (carbon-based) chemicals that evaporate readily at room temperature. VOCs typically are found in high indoor concentrations in dry-cleaned clothing; chloroform from chlorinated water; benzene from tobacco smoke; (formaldehyde from fabrics, pressed wood products and insulation; styrene found in adhesives, foam, lubricants, plastics, carpets and insulation; methylene chloride from paint strippers; and carbon tetrachloride from paint removers.


Other potential sources of indoor air pollution are central heating, cooling and dehumidification systems, household cleaning and maintenance products, outdoor sources such as pesticides, and biological contaminants such as animal dander, mold and cockroaches.

While indoor air pollution affects people differently, in general, short-term exposure might cause immediate effects such as headaches, dizziness and allergies. Long-term exposures can result in respiratory disease, heart disease and cancer.

Building-related illness is an identifiable disease or illness that can be traced to a specific pollutant or source within a building. In contrast, the term “sick building syndrome” is used to describe situations in which building occupants experience acute health and comfort effects that appear to be linked to time spent in a building, but where no specific illness or cause can be identified. Both syndromes are associated with acute or immediate health problems.

Awareness is the first step in creating a more healthful indoor environment. Your best defense against indoor air pollution is a strong offense. First, identify and control sources of pollution to reduce and prevent indoor air contamination.

This can range from changing housecleaning products to airing out freshly dry-cleaned clothing to tossing out formaldehyde-containing furniture. Equally important is improving ventilation. Proper ventilation--the mixing of indoor air with outdoor air--can revitalize the air in your home.

Because cigarette smoke is one of the single greatest contributors to indoor air pollution, smoking indoors is inadvisable. Similarly, fireplaces and other fuel-burning appliances (water heaters, furnaces, stoves, etc.) should be properly adjusted and vented to the exterior. Doing so will prevent carbon monoxide poisoning and improve efficiency of the appliance.


Adequately sized exhaust fans should be used wherever moisture and combustion are present in the bathroom, laundry and kitchen. A bath fan, for example, will help to dissipate chloroform gas, which is a byproduct of chlorinated water.

There are other indoor air pollutants that deserve your attention, such as asbestos, lead and radon. The first two were used pervasively in building products before being outlawed by the EPA in the late 1970s. The rule with asbestos and lead is that it is best left alone if it is not peeling or crumbling.

Asbestos or lead should not be scraped or sanded and should be removed only by a professional abatement contractor with the proper equipment. Moreover, testing should be performed after the abatement process to ensure the air quality is safe.

Radon, on the other hand, is a naturally occurring gas derived from uranium in the ground. Radon can make its way into a home through cracks in the foundation or basement walls. Small amounts of radon can be controlled by sealing cracks with a caulking or patching compound. Higher levels might require the installation of an exhaust system.

For more information on indoor air pollution and what to do about it, visit the EPA’s Web site at or the American Lung Assn. Web site at


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