They make a constant din and cause acute pollution.

这些摩托车喧嚣不断，还会造成严重污染。

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If these targets were to be achieved, significant reductions in risks for acute and chronic health effects from air pollution can be expected.

如果能够实现这些目标，可望大量减少空气污染对健康带来的急性和慢性影响。

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Indoor air pollution associated with the still-widespread use of biomass fuels kills nearly one million children annually, mostly as a result of acute respiratory infections.

与仍然广泛使用生物质燃料有关的室内空气污染每年造成约100万儿童死亡，主要由急性呼吸道感染引起。

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"The pollution issues are even more acute in the big urban areas,".

VOA: standard.2009.03.23

Pollution from them causes chronic and acute respiratory ailments and premature death, and it contributes to global warming.

NPR: EPA Proposal Eases Rules on Pollution Controls

The problem is most acute in the Central Valley, where nearby mountains tend to trap the pollution sent to the skies from heavy auto traffic and other machinery.

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