According to the American Lung Association of the Mid-Atlantic Web site, "hundreds of potentially harmful chemicals are emitted by household cleaning agents ... Such chemicals can cause dizziness, nausea, allergic reactions, eye, skin, respiratory tract irritation, and cancer."

Indoor air quality also can affect asthma, said Laura Quinn, communications director of the Mid-Atlantic region. May is Asthma Awareness Month. The lung association recommends ensuring adequate ventilation when using chemicals or finding an alternative to them.

"In Building Biology, we say, 'Open the windows' because you need fresh air inside your house," said Jeanne McLaughlin, certified as a building biology and ecology consultant with the Institute of Building Biology and Ecology, IEB.

In Western Pennsylvania, though, she adds a caveat to that statement. "We have to be careful here. Check the outside air quality on the Weather Channel before you open up your house. Sometimes the air outside is worse than the air inside."

Plants are natural air cleaners, yet some are better than others. Good for cleaning the air are spider plants and the peace lily for example, McLaughlin said. "The broader the leaf, the better," she said.

"I think it's very important to have plants inside. Some people say that plants will encourage mold but you can put aquarium stone on the top of the dirt in the pot to keep the moisture in and any mold down," McLaughlin said.

She also noted that plants are hygroscopic. "If there's too much humidity in the air then the plants will take it in. If there's not enough humidity, plants will release it," she explained.

Commercial air cleaners like Trane, SpaceGard and April Air are all good, McLaughlin said. "But those air cleaners are mostly to protect your furnace, not you."

So McLaughlin also uses a portable air cleaner, wheeling it from room to room periodically. She even moves it into closets once in a while to remove the glue and rubber smells from shoes and other odors.

Indoor air quality also can be affected by radon, a colorless, odorless gas that naturally comes from the ground.

"We do sit pretty much on a radon belt here, so it is advisable for people who live around here to have their homes tested," said Carole Toubakaris, family and consumer science educator with the Penn State Cooperative Extension office in Butler.

"I also want to say if you are buying a home and you see the venting and fan to remove a home's radon, that's not a scary thing. That's just a sign that it's already been taken care of," she added.