空氣污染知多少:細數5大空氣污染源

1. Power Generation
1. 發電污染

Siting fossil fuel power stations in mainly rural areas and distributing the pollution produced more evenly via tall chimneys has resulted in improved urban air quality, though they still remain a major source of pollution, mainly sulphur dioxide and nitrogen oxides.
將化石燃料發電站建在郊區，造高煙囪讓污染物更平均地分佈在各處，這些當然能讓城市的空氣變得更好。不過，發電依舊是一個很大的污染源，主要的污染物是二氧化硫和一氧化氮。

Better dispersion of pollutants emitted by tall chimneys leads to better dilution in the air and thus lower local concentrations of pollutants. This has however led to pollution being dispersed more widely and to transboundary air pollution.
高的煙囪能夠讓污染物在空氣中散佈得更均勻，可以更好地稀釋污染物，讓污染物的濃度降低。然而，這卻致使污染物分佈得更廣泛，並且會使空氣污染向其他區域傳播。

2. Other Industry and waste disposal
2. 其他工業和廢物污染源

Although fossil fuel power plants are the major source of industrial air pollution in many countries, all industry and many businesses, large and small, can be significant local sources of a wide range of air pollutants.
雖然化石燃料發電站是很多國家最主要的工業造成的空氣污染，但是所有工業以及其他很多行業，無論大小，都有可能成爲當地各種類型空氣污染的源頭。

All waste has the potential to affect the environment adversely by contaminating the air, soil or water. Poorly managed waste disposal sites (landfill or incineration) can also pose a danger to public health, through all these routes.
所有的廢棄物都有可能對環境產生不利影響，污染空氣、土壤和水質。如果不對廢物處理處（垃圾填埋場或焚燒廠）善加處理，這些廢物也有可能通過各種途徑對公衆的健康造成影響。3. Road Transport
3. 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 individual vehicles are in danger of being overtaken by increases in the volume of traffic.
機動車輛造成的空氣污染在很多國家都已經超過了煤煙，成爲了最大的空氣污染源。持續增加的車輛使用數量也意味着：減少單部車輛排放的速度已經快要趕不上車流量增加的速度了。

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.
機動車輛製造的空氣污染會帶來兩個階段的問題：一級污染物和二次污染物。一級污染物是由汽油動力車輛產生的，包括一氧化碳、氧化氮、苯、懸浮顆粒以及鉛。很多消耗汽油的車輛所排放的鉛最成爲空氣中的懸浮顆粒。二次污染物是由汽油引擎車輛產生的，包括二氧化氮和臭氧。

4. Domestic Sources
4. 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:
由於溫度驟降，中國北部地區的家庭中燃煤，成爲了一個主要的空氣污染源。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.
爐竈會產生一氧化碳。如果通風不佳或設備維護不周，一氧化碳有可能會在家中聚集，達到會造成危險的濃度。同時還會產生的是二氧化氮，使用炊具時，廚房內的二氧化氮濃度會比室外的濃度高。

Bonfires, garden incinerators and barbecues can be a significant local smoke and odour nuisance. Burning garden waste produces smoke, especially if it is damp and smouldering rather than dry and blazing. The smoke contains CO and other noxious and irritating compounds. Problems may be caused for asthmatics, bronchitis sufferers or those with heart conditions. Even if the immediate health risk is small, bonfires add to the general background level of air pollution.
篝火、花園裏的焚化爐和戶外燒烤都有可能產生大量煙霧和難聞的味道。燃燒花園中的廢棄物時會產生煙霧，特別是廢棄物潮溼時，燃燒產生的煙霧要比干燥時產生的煙霧多。煙霧中還有一氧化碳和其他有毒、刺激性化合物。這些污染對有哮喘、支氣管炎以及心臟疾病的人來說會造成不良後果。即使在短時間內沒有很大的健康風險，篝火產生的污染也會增加大環境下的空氣污染程度。

5. Agriculture
5. 農業污染

Agricultural practices can also be a significant source of nuisance, contributing both to local levels of air pollution and causing odour problems. The main sources of pollution are the burning of agricultural waste, or of crops in the field and large intensive livestock units. Depending on soil type and fertilisation, the nitrogen in the dung and urine of grazing cattle contributes 20-40% of nitrous oxide emissions from agricultural land; methane is also emitted by cattle and other ruminants; nitrous oxide and methane are of course both greenhouse gases.
農業活動也有可能成爲討厭的空氣污染源，即會增加當地的空氣污染程度，也會產生難聞的氣味。農業污染最主要的的源頭是焚燒農業廢棄物、農田中的農作物，大量的牲畜也是一大農業污染源。牛的糞便和尿液是農業一氧化二氮排放的原因之一，根據土壤類型和土壤肥沃程度不同，其排放的一氧化二氮的比例會佔到總量的20-40%左右。牛和其他反芻動物還會排放加完，而一氧化二氮和甲烷都是溫室氣體。