According to the Environmental Protection Agency, levels of indoor air pollution can be up to 5 times—and occasionally up to 100 times—higher than levels outside. Want to breathe easy? Try these quick, inexpensive solutions.

Change your air filter. Replace your standard filter with one that is pleated and electrostatic, suggests Robert Moffitt, communications director for the American Lung Association Health House program (online at www.healthhouse.org). Look for a minimum efficiency reporting value (MERV) rating of ten or higher.

Ventilate. If you have ventilation fans in the bathroom and kitchen, use them. High levels of humidity breed mold and mildew. Microscopic particles from these can trigger allergies, asthma attacks, and, in rare cases, lung infection or poisoning.

Pick cleaning products with care. A wide range of ingredients in air fresheners and cleaning agents are known causes of health problems, including cancer and respiratory ailments, says Samuel Epstein, MD, chairman of the Cancer Prevention Coalition. So go with nontoxic products (or make your own cleansers) whenever possible.

Purify with plants. Houseplants can remove common chemicals from the air, such as formaldehyde, benzene, and carbon monoxide. Some plants actually thrive on them! Peace lilies, bamboo, palms, English ivy, mums, and gerbera daisies are among the top air-purifying types.