You wouldn't knowingly eat a dangerous substance, so why would you want to breathe one in? According to a recent paper published by the Natural Resources Defense Council (NRDC), chemicals called phthalates (pronounced “thalates”) were found in 86 percent of commercially available air fresheners tested. Manufacturers use phthalates to help air-freshener and perfume droplets stay suspended in air. They are also used as softening agents in everything from lotion to nail polish to plastic toys. Unfortunately, phthalates are suspected endocrine disruptors that have been linked to the abnormal development of male reproductive systems.

“Phthalates have a lot of uses, which is why they are in so many consumer products,” says Gina Solomon, MD, MPH, a senior scientist at the NRDC. “And they are only rarely included in ingredients lists, so this creates a buyer-beware situation in which you can't assume that products have been regulated and tested for safety.” Last October, California became the first state to ban children's products that contain more than one tenth of 1 percent of phthalates.

Instead of spraying an air freshener in a smelly room, Solomon suggests eliminating the odor's source by opening a window, taking out the trash, or using baking soda or natural cleaning agents.