Carbon monoxide (CO) is a colorless, odorless, poisonous gas, slightly lighter than air, that is produced by the incomplete burning of carbon in fuels. The main sources are internal combustion engines, mostly in motor vehicles.

• 一氧化碳（co）是一种无色无味的有毒气体，比空气稍轻，这是由燃料中的炭不能完全燃烧生成的，主要来源是内燃机，大多产生于机动车辆。