On the periphery of its range, populations have declined, primarily due to habitat modification, dam construction, river flow modification, wetland drainage, and pollution.

但是在边缘地带，其数量有所减少，主要归咎于其生活环境的改变、水坝建设、河流改道、湿地干涸以及环境污染。

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Fuel consumption and pollution might be reduced by smoothing traffic flow and running vehicles close enough to each other to benefit from aerodynamic drafting.

车流通畅，相互紧随行驶的车辆能利用前车产生的较小的空气阻力，这些都可能减少油耗和污染。

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Discharge valve can be will collect the liquid and solid particle emissions, prevent the liquid flow off the downstream, the pollution downstream compressed air system.

排放阀可以将收集的液体和固体微粒排放掉，防止液体流向下游端，污染下游端的压缩空气系统。

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He added that the authority would analyse data from the scheme and was committed to working with KCC to tackle the city's traffic problems, lower pollution, ease flow, and find a permanent solution at Westgate Towers.

BBC: Westgate Towers road scheme 'dividing Canterbury' ends

"The pollution indoors is generally higher than outdoors, possibly because of an imbalance between the flow of pollutant from outside and its removal from inside to outside, " the researchers say.

BBC: Is your floor a health hazard?