Here’s What Gives Pools That Chlorine-y Smell (Spoiler: It’s Gross)

“If we don’t shower before we get in the water, we’re going to carry in whatever’s sitting on our skin,” says Michele Hlavsa, RN, MPH, an epidemiologist and the chief of Healthy Swimming and Waterborne Disease Prevention at the CDC. That includes natural oils, sweat, makeup and other personal care products, urine and, yep, fecal matter.