There’s something about the smell of the inside of a new car. That something many of us enjoy is actually the smell of volatile organic compounds given off by various interior materials, such as carpeting and upholstery. Within acceptable levels we may not notice any ill-effects, but a study in PNAS Nexus found the new car smell may reach toxic levels on hot days. Beijing researchers say when outside temperatures ranged between seventy-seven and one hundred fifteen degrees, new car interiors had higher-than-acceptable levels of various VOCs, including formaldehyde—sometimes double acceptable limits. Other than properly ventilating car interiors on hot days, authors suggest developing control systems for new cars of the future.