Thursday’s column noted the history of car air-conditioning, dating back to 1933 and advances from 1940 to 1952. Vehicle components emit a cancer-causing carcinogen, benzene, that increases when parked cars are exposed to sunlight. Car manufacturers suggest vacating the internal heat by opening the windows first and activating the air conditioner second. I got a note to the column from a viewer who said researchers at ExxonMobil are extracting citrus oil from orange and lemon peels to eliminate benzene in vehicles. Using a hydrocarbon substitute involves manipulating molecules in similar ways that polymers are processed. As dashboards, steering wheels, seat covers and other plastic components have been implemented in the past, future vehicles may include the same components made from citrus products. Fastcast: Muggy, showers.