空气污染源(2)

3. Road Transport
道路交通污染
Air pollution from motor vehicles has, in many countries, replaced coal smoke as the major cause for concern; and the continuing growth in vehicle use means that efforts to reduce emissions from inp>
机动车辆造成的空气污染在很多国家都已经超过了煤烟，成为了最大的空气污染源。持续增加的车辆使用数量也意味着：减少单部车辆排放的速度已经快要赶不上车流量增加的速度了。
The air pollutants produced as a result of the use of motor vehicles present a two-stage problem: primary and secondary pollutants. Primary pollutants produced by petrol-powered vehicles include carbon monoxide, nitric oxide, benzene, particulate matter and lead. Much of the lead emitted by vehicles burning leaded petrol emerges as particles. Secondary pollutants produced as a result of the use of petrol-engined vehicles include nitrogen dioxide and ozone.
机动车辆制造的空气污染会带来两个阶段的问题：一级污染物和二次污染物。一级污染物是由汽油动力车辆产生的，包括一氧化碳、氧化氮、苯、悬浮颗粒以及铅。很多消耗汽油的车辆所排放的铅最成为空气中的悬浮颗粒。二次污染物是由汽油引擎车辆产生的，包括二氧化氮和臭氧。
4. Domestic Sources
生活污染源
As temperatures across the region plummeted, domestic burning of coal across northern China becomes the primary source of air pollution. Other important domestic sources of air pollution are:
由于温度骤降，中国北部地区的家庭中燃煤，成为了一个主要的空气污染源。其他重要生活污染源有：
Stoves and cookers produce carbon monoxide. If ventilation is inadequate or appliances poorly maintained, CO may accumulate in dangerous concentrations. Nitrogen dioxide is also generated and concentrations in kitchens will usually exceed those outdoors when cookers are in use.
炉灶会产生一氧化碳。如果通风不佳或设备维护不周，一氧化碳有可能会在家中聚集，达到会造成危险的浓度。同时还会产生的是二氧化氮，使用炊具时，厨房内的二氧化氮浓度会比室外的浓度高。