Although they make your home smell like pine needles, there’s nothing natural about most commercial air fresheners. In fact, research suggests that they contain chemicals that can harm our health. A recent analysis of two Glade air fresheners by Missoula, Mont.-based nonprofit Women’s Voices for the Earth (WVE) found that both contained allergens and one contained synthetic musks, which build up in our bodies and are potential hormone disrupters. In 2007, the Natural Resources Defense Council tested 14 common air fresheners and found phthalates in 12 of them. “By law, companies aren’t required to list the ingredients in their products, which means that most of them keep fragrance ingredients a secret,” says Cassidy Randall, director of outreach and engagement for WVE. “When fragrance makes up 70 to 80 percent of an air freshener, we really have no idea what we’re spraying in our homes.”