Clearing the air on home pollutants

Smelling noxious fumes on a busy highway or near an airport, you may wish you were safe at home breathing clean air. Actually, the air at home may be as much in need of a good cleanup as the air on the road or near a factory. A growing body of scientific evidence shows that the air you breathe at home, whether you live in the city, the country, or the suburb, is often more polluted than the air outside. Most people spend more time indoors than out, and more time at home than anywhere else. Some experts cite “the rule of 1,000.” This means that pollutants released indoors are 1,000 times more important in causing human exposure than the same pollutants outdoors.

Tobacco smoke is, by far, the worst pollutant, but even if you have a smoke-free home, many things can dirty the air, notably the following:

• Cooking, especially on a gas range; burning incense or candles; or any form of combustion.

• Air fresheners and deodorizers.

• Insecticides, including mothballs.

Should You Worry?

How much should you worry? Some indoor pollutants, such as carbon monoxide, are toxic and even lethal at high levels, and you should keep them under strict control. Others, such as the volatile substances that evaporate from dry cleaning or air fresheners, are potentially carcinogenic at high levels, but no one knows what effects they may have at the levels commonly measured in homes (see table). Nobody is saying that burning a scented candle will make you sick, let alone kill you. There’s no evidence that brief, low-level exposure even to powerful chemicals like DDT will cause any harm. Some researchers suspect that some home pollutants might promote heart attacks or breast cancer, but there is no evidence that this is so. People with asthma or those with lung or cardiovascular diseases are most susceptible to indoor pollutants. Even low levels of pollutants may actually make them sick.

There is a lot to learn. The link — if there is one — between air pollution in the home and health is of growing interest to scientists. In a two-year experiment, Dr. Lance Wallace, who works for the US Environment Protection Agency (EPA), used his own home as a laboratory; he lives in a town house with a basement and two upper floors. State-of-the-art equipment measured the levels and size of microscopic particles created by one of the biggest contributors to home pollution: cooking on a gas range, which produces large quantities of microscopic particles.

In the Wallace home, frying or sautéing on the gas stove produced high levels of such particles; even making a toast in a clean new toaster produced some. Wallace was not sure how the particles were formed — probably a combination of the fuel itself with the cooking oils and other foods, and in the case of the toaster, the coatings on the metal. The good news: Adequate ventilation and a central fan were able to remove the particles.

The moral of the story, in fact, is that it’s usually in your power to control or eliminate pollutants at home. We all have to cook, run the vacuum cleaner occasionally, or turn on the air conditioner. There’s no such thing as a combustion-free, dust-free, particle-free home. Carbon monoxide and tobacco smoke can and should be eliminated; other pollutants can be controlled. Sometimes it’s simple — for example, nobody really needs air fresheners or mothballs. Sometimes, it’s expensive, as with repairing a leaking roof or reducing radon in the basement. Sometimes, it’s a matter of following good practices — regularly cleaning ovens, air conditioners, and other home appliances.

How To Detect A Problem

Many pollutants are not visible or detectable by smell. Still, if you notice unpleasant smells, or if you constantly feel the need to cover up odors, you have a problem.

Ironically, if you live in a well-insulated, energy-efficient home where windows and doors fit tightly, you are more likely to have polluted air than if you live in a drafty house with poor insulation and old windows and doors. On the plus side, a new house is more likely to have vented range hoods and bathrooms with exhaust fans.

Physical signs of exposure include symptoms that hit more than one household member at once; headaches that seem to bother you when you’re at home but clear up when you leave; fatigue, irritated eyes, coughing, skin rashes, and dizziness. The adverse effects depend on individual sensitivities, as well as the levels and types of pollutants.

Ventilation Is The Key

Maintaining a flow of air in your living space is the basic way to combat indoor pollution. Open windows and doors as often as possible. The second step is to use venting systems in bathrooms, kitchens, and any room with woodstove or range. If you have no venting hood on your cook stove, at least open a window, turn on a window fan, or run the air conditioner with the vent open. Cut back on cooking methods that produce the most pollution, such as frying or sautéing.

Signs of poor ventilation include moisture collecting on windows or walls, an air conditioner that smells bad, items on a shelf or in a closet that turn musty, or perpetually stale bathroom air.

Other Steps To Better Indoor Air

• Don’t smoke or allow smoking in your room.

• Be sure all appliances are properly vented. If you have a vent fan, use it.

• Don’t use air fresheners, scented candles, incense, and the like. They mask rather than remove odors. Air fresheners actually pollute indoor air with such potential carcinogens as paradichlorobenzene and limonene; scented candles produce polyaromatic hydrocarbons (PAHs, like those produced by charbroiling).

• Avoid mothballs. They produce paradichlorobenzene and napthaline fumes, which, if inhaled in sufficient amounts, can make you sick. People sometimes wear sweaters (or sleep under blankets) that smell of mothballs — not a great idea. To combat moths, clean cloths before storing; wash washables and dry-clean woolens. Store clothes in airtight containers without mothballs.

• Newly dry-cleaned clothes can temporarily raise pollution levels. If you notice a chemical smell, remove the plastic bags and air the clothing out — outdoors if possible — before wearing.

• Wash new permanent-press and cotton fabrics (especially linens and towels) before use. Many labels direct you to do so. This gets rid of sizing and other chemicals.

• Use a high-quality doormat, since shoes can track in pesticides, dirt, and other kinds of pollutant.

• Vacuum floors and rugs frequently. If you have allergies – especially to dust, dander, dust mites, or pollen – get microfiltration bags for your vacuum cleaner. These have a two-ply design that can trap many of the smallest particles. Consider buying a vacuum cleaner with a HEPA (high-efficiency particulate-arresting) filter.

• If you are buying and/or installing new carpet, ask the retailer for carpet, padding, and adhesives that have the lowest emissions. Increase ventilation for two or three days after installation.

• Be sure your bathroom is properly vented, and use the fan when you’re showering or bathing. Open a window; run the vent fan to disperse bathroom smells; don’t use deodorants.

• Use hair spray, nail polish, polish removers, and spray perfume sparingly and in well-ventilated areas.

• Use pesticides sparingly, too. Investigate non-chemical methods. Consider using a pest control company for persistent problems. Ask in advance how it plans to minimize exposure for humans and pets.

• To control mold, keep indoor humidity as low as possible (below 50 percent). Use air conditioners in warm and humid weather.

• Don’t rely on air-cleaning machines. Though the best portable and in-duct machines can reduce some fine particles when used correctly, independent studies have shown that they do not remove gaseous pollutants or ultra-fine particles from indoor airs, destroy microbes, remove odors or control most allergens. No studies have clearly shown that these machines provide health benefits. In no case should portable devices be used in small, poorly ventilated rooms. They may produce ozone, a dangerous pollutant. According to the EPA, air-filtering machines are helpful only when combined with good ventilation and source control.