What about the air in my home?

Indoor air can be even more polluted than outdoor air. Blame fuel oils, smoke, mold, pesticides, radon, and the chemicals used during the manufacture of everything from permanent-press clothing to particleboard. (For a more complete list of common household pollutants, go to Clean Air Information.) You can’t avoid indoor air pollution entirely, but there’s a lot you can do to reduce it.

Ban smoking, especially if you have kids. “The single most important thing you can do to improve the quality of your air is to not allow smoking in your home,” says Norman Edelman, M.D., chief medical officer of the American Lung Association.

Open the windows. When the weather is nice, let fresh air in to help dispel household fumes — except on air-alert days or if you live on a busy road. Leave doors open between rooms, and run freestanding and whole-house fans to keep air circulating.

Keep humidity in check. Install outside-venting fans in the kitchen, the bathrooms, and the laundry room; place a dehumidifier in the basement; and make sure the attic and crawl spaces are vented to help dry any excess moisture that could create a breeding ground for mold. Relative humidity in your home should be between 30 and 50 percent. Higher levels can lead to potentially toxic mold growth. Measure your level with an inexpensive hardware-store hygrometer.

Use fireplaces sparingly. Wood fires release particles, and wood smoke can irritate lungs and trigger infections and asthma attacks.

Maintain appliances. Clean air-conditioner filters every spring, and have the furnace, the fireplace, and the chimney checked every fall to make sure they’re operating and venting as they should. Water heaters and gas appliances should get an annual checkup, too.

Clean humidifiers and appliance drip trays regularly. If you don’t, they can become petri dishes for mold, germs, and other airborne toxins.

Don’t clean your air ducts. There’s no proof that it prevents health problems or even that dirty ducts add to indoor pollution. Cleaning can actually send debris into the air again. The EPA recommends duct cleaning only if dust is spewing from your vents or you have mold, a pest infestation, or a clog.

Don’t stir up dust. Feather dusting and sweeping send particles right back into the air. Instead, use a magnetic duster or an electrostatic cloth, which creates a static-electricity charge that traps dust (or you can use a damp rag), and vacuum rather than sweep.

Use chemicals with care. Open windows and doors and run a fan when you’re painting or using heavy-duty cleaners. Or try alternatives, like paints with few or no volatile organic compounds (VOCs), such as those made by Benjamin Moore and Sherwin-Williams. Buy cleaners in squeeze or pump bottles instead of aerosol cans. If you have pests, try traps before using bug sprays or bombs.