a compound (= a chemical that combines two or more elements) containing carbon that changes easily into a gas and that can be harmful to people's health or to the environment

Nitrogen oxide mixes in sunlight with chemical gases called volatile organic compounds, or VOCs, to form the smog ingredient ozone. 氮氧化物与一种被称为挥发性有机物，又称VOC的化学气体混合，在阳光下形成雾霾的成份臭氧。

The company has been using a citrus-based product with no volatile organic compounds or hazardous constituents. 这家公司一直在用一种由柑橘制成的产品，无需使用挥发性有机物或有害组份。