Regular use of household cleaning sprays and air freshener may increase the risk of adult-onset asthma, according to a new study published in the American Journal of Respiratory and Critical Care Medicine.

Researchers analyzed data from the European Community Respiratory Health Survey, which collected epidemiological data at 22 centers in 10 countries. They followed this up with face-to-face interviews of 3,503 people who did the cleaning in their home and were free of asthma when the study began. Participants answered questions about the frequency of their use of 15 kinds of cleaning products. the researchers then followed up nine years later, using an interview to determine the participants’ current asthma and wheeze levels, and the occurrence of physician-diagnosed asthma and allergy.

Those who used cleaning sprays at least once per week were 50 percent more likely to have increased asthma symptoms, wheeze, or asthma medication use in nine years than those who used such products less frequently. those who used sprays at least four times per week were significantly more likely to have been diagnosed with asthma by a physician than those who used them less frequently. the strongest association was found with air freshener, glass cleaners and furniture-cleaning sprays.

The researchers found no association between the use of non-spray cleaners, such as solvent stain removers and washing powders, and the incidence of asthma. there was also no apparent asthma increase associated with infrequently used spray products, such as oven cleaners.

“Even a small reduction in lung function may indicate some harm to the lungs,” said lead NIEHS researcher Stephanie London, M.D. “The best way to protect yourself, especially children who may have asthma or other respiratory illnesses, is to reduce the use of products and materials that contain these compounds.”

The study — published in Environmental Health Perspectives — analyzed the effect of volatile organic compounds (VOCs) such as 1,4 DCB on the lung function of 953 adult men and women. Of the chemicals studied, which included VOCs benzene, toluene and acetone, only 1,4 DCB was linked to a reduction in pulmonary function; a link found to be significant even when smoking was factored in.

The chemical 1,4 DCB is usually found in space deodorizing products, such as room fresheners, urinal cakes and toilet bowl fresheners, and is used as an insecticide for moth control, according to the HIEHS. it can also be found in things like tobacco smoke, paints, cleaning products and vehicle exhausts, and is detectable in 96 percent of population blood samples, with blacks showing the highest levels and non-Hispanic whites showing the lowest.

Many common consumer products contain dangerous chemicals that harm human health and promote cancer, says author Randall Fitzgerald in his book the Hundred-Year Lie. Numerous household products expose consumers to harmful chemicals, including air freshener, deodorant products, antibacterial soaps and many more.