Household cleaners, personal care products, perfumes, and other consumer and industrial products emit chemicals known as volatile organic compounds, or VOCs. Researchers led by scientists from the National Oceanic and Atmospheric Administration found that as cars have gotten cleaner, tailpipe emissions have gone down. As a result, the researchers estimate that emissions from consumer and industrial products now contribute half of the VOCs that cause air pollution.

Some studies have found that leaner people diagnosed with several different cancer types have a higher risk of dying than those who, according to their body mass index (BMI), are overweight or mildly obese. Similar findings have been reported in diseases other than cancer, and the phenomenon has come to be known as the “obesity paradox”—the idea that having some excess body fat offers a measure of protection against disease-related death.