Indoor asthma.

My asthma seems to act up more indoors than out. why might that be?

David L., email

There are a lot of asthma triggers indoors, dust or mold being two of the most well known. But a less-recognized trigger sits on counters and tables across the country--scented air fresheners. "This is a much bigger problem than people realize," said Stanley Fineman, M.D., president of the American College of Allergy, Asthma and Immunology. "About 34 percent of people with asthma report health problems from air fresheners."

Home fragrance products may smell fresh, but Dr. Fineman warns that many of these products contain volatile organic compounds (VOCs) and are merely covering up--not eliminating--odors in the home. VOCs commonly found in air fresheners include formaldehyde, petroleum distillates, limonene, esters, and alcohols. If asthma flares up every time you enter your house, maybe it's time to eliminate air fresheners and try letting your house go au naturel.