As a source of cleaner energy, the natural gas is able to reduce the air pollution by burning coal.

天然气作为一种清洁能源，能够减少燃煤造成的大气污染。

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The natural degradation speed of the pollution of chemical pollutants in the soil is very slow under a natural condition, so a long-time pollution source to underground water is formed.

土壤中的化学污染物在自然条件下污染自然降解速度非常缓慢，形成对地下水的长期污染源。

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Objective: to understand the pollution of the Yellow River in HuiNong of NingXia Autonomous Prefecture and in natural water source and running water quality.

前言：目的：掌握黄河水源宁夏惠农段污染现状和目前自来水水质现状。

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