急！请哪位英语高手帮忙翻译一下下面的一篇文章，机器翻译的止步！在线等，谢谢!

太长了，但还是杜绝机译，请楼主审阅，并加分。谢谢 Air Pollution 空气污染 There are many chemicals that pollute the air. 污染空气的化学品有好多种。In cities, the major source of pollution is carbon monoxide. Carbon monoxide is caused most of the time by gasoline-powered motor vehicles.在城市里，主要的