In a grim development for allergy sufferers in North America, a new investigation warns that pollen seasons are getting longer and worse. Over the last three decades, the annual pollen season has expanded by nearly three weeks, accompanied by a 21% jump in pollen concentrations. A big underlying cause: climate change. “It is clear that…  read on >  read on >

The microbes on your toothbrush mostly come from your mouth — not your toilet — and provide insight into your oral health, researchers say. Their study was inspired by people’s concerns that flushing a toilet might create a cloud of aerosol particles that end up on toothbrushes and other bathroom surfaces. The researchers asked people…  read on >  read on >