As well as the noise, traffic, loss of arable land and threat to birds, airports are a major source of pollution and greenhouse gas emissions.

机场不仅导致了噪声、交通堵塞、耕地流失，威胁鸟类，还是主要的污染源和温室气体排放源。

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Crop straw is rich in resources, extensive in use, but if not effectively used, it will become a huge source of pollution.

我国农作物秸秆资源丰富，秸秆资源用途广泛，但如果不能有效利用，反而会成为巨大的污染源。

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The study on elemental speciation in airborne particulate matter (PM) is important for its evaluation of toxicity and source of pollution.

大气颗粒物中元素的种态研究，对评价其毒性和污染来源等有很重要的意义。

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Mr. Bahtiarian says the main source of noise pollution is the propeller.

VOA: special.2011.06.29

In developing countries, the main source of water pollution is not stormwater,but waste water.

VOA: standard.2010.08.04

The Environmental Protection Agency used its authority to regulate carbon dioxide as a source of pollution and set higher standards for power plants.

CNN: Obama needs to lay out a plan on climate crisis

This will allow truckers to reduce emissions significantly (diesel emissions include nitrous oxides, particulate matter, and other air toxics and they are a major source of pollution in some areas).

FORBES: Acceleration of the Natural Gas Highway

It has led to deforestation in countries like Brazil, for instance, and, in countries belonging to the Organisation for Economic Co-operation and Development (OECD), intensive livestock production has become a major source of pollution.

UNESCO: World Water Assessment Programme (WWAP)