为控制新冠肺炎疫情的蔓延，多国采取封锁措施，民众无必需不得外出，交通流量大幅减少，这使得空气污染水平出现大幅下降。伦敦的PM2.5水平约为往年同期正常水平的一半。
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The level of air pollution in London, Rome, Milan and Paris has fallen sharply since coronavirus lockdown measures have forced people indoors and off the roads.
因新冠肺炎疫情封锁措施，多地民众被迫待在家中，不再上街，伦敦、罗马、米兰和巴黎的空气污染水平大幅下降。
Levels of particulate matter, which can come from road transport and burning fuel, as well as nitrogen dioxide, which comes primarily from vehicle exhausts, are low across London.
在伦敦，来自公路运输和燃料燃烧的颗粒物，以及主要来自汽车尾气的二氧化氮的含量都很低。
The UK capital's levels of ultra-fine particulate matter, known as PM2.5, are currently around half that would be normally recorded at this time of year.
目前，伦敦的超细颗粒物（PM2.5）水平约为往年同期正常水平的一半。
The city's level of nitrogen dioxide has also been lower than the average for the previous five years, scientists say.
科学家表示，伦敦空气中的二氧化氮水平也低于过去5年的平均水平。
Both pollutants have fallen by around a half since a peak in mid-February, according to data from the London Air Quality Network, analysed by the National Centre for Atmospheric Science.
根据英国国家大气科学中心分析的伦敦空气质量网络数据，这两种污染物的水平自2月中旬达到峰值以来，已下降了约一半。
Meanwhile, European Environment Agency (EEA) data confirmed a 50 percent decrease in air pollutant concentrations in Rome and Milan.
与此同时，欧洲环境署的数据证实，罗马和米兰的空气污染物浓度下降了50%。
A Paris air quality monitoring agency has also recorded up to a 30 percent decline in overall air pollution levels there.
巴黎一家空气质量监测机构的数据显示，巴黎的整体空气污染水平下降了30%。
As daily life grinds to a halt in the UK due to restricted movement to control the spread of COVID-19, air quality has improved due to a sharp reduction in traffic.
在英国，为了控制新冠病毒的传播，人们被限制出行，日常生活逐渐陷入停滞，而随着交通流量的急剧减少，空气质量也得以改善。
‘Air quality has started to improve in many UK cities, mirroring what has been seen in other countries that have restricted travel and levels of outdoor activity,’ said Professor Alastair Lewis, from the National Centre for Atmospheric Science, University of York.
约克大学国家大气科学中心的阿拉斯泰尔·刘易斯教授说：“英国许多城市的空气质量已经开始改善，这与其他限制旅行和户外活动的国家情况一致。”
‘This is primarily a consequence of lower traffic volumes, and some of the most clear reductions have been in nitrogen dioxide, which comes primarily from vehicle exhaust.
“这主要是交通流量减少的结果，而二氧化氮的减少最为明显，二氧化氮主要来自汽车尾气。”
‘However fine particles (PM2.5) have also reduced significantly.
“不过，PM2.5也显著减少。”
‘In London for example, PM2.5 is noticeably lower than would be expected for this time of year at the roadside, and these reductions stretch through into the suburbs as well.’
“以伦敦为例，路边的PM2.5浓度明显低于往年同期水平，而且郊区也出现了这种下降趋势。”
Professor Lewis said it's especially important to consider how PM2.5 levels have changed compared to what is normally seen at this time of year.
刘易斯教授表示，目前尤为重要的是要思考PM2.5水平与往年同期相比发生了怎样的变化。
While nitrogen dioxide is mainly emitted from vehicle exhausts, sources of particulate matter are more varied, ranging from road transport to burning fuel.
虽然二氧化氮主要来自汽车尾气，但颗粒物的来源更为多样，包括道路运输和燃烧燃料等。
Air pollution is linked to health problems including stroke, heart disease, lung cancer and disease, and respiratory diseases and infections, as well as stunting the growth of children's lungs.
空气污染与健康问题有关，包括中风、心脏病、肺癌和肺病，以及呼吸道疾病和感染，还会阻碍儿童肺部的发育。
Professor William Collins, professor of meteorology at the University of Reading, said a large amount of the air pollution that is breathed in comes from traffic.
雷丁大学气象学教授威廉·柯林斯表示，人们吸入的空气污染物主要来自交通污染。
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And as levels of traffic pollution have plummeted with many countries in lockdown, exposure to pollutants is reduced by people staying off the streets and in their homes.
随着多国实行封闭措施，交通污染水平大幅下降。人们远离街道并待在家里，减少了接触污染物的机会。
France's stay-at-home orders to combat the coronavirus outbreak have produced a 20 to 30 percent decline in overall air pollution levels in Paris, according to a report from the region's air quality monitoring agency.
根据法国空气质量监测机构的一份报告，法国为抗击新冠肺炎疫情而下达的居家命令已经使巴黎的整体空气污染水平下降了20%到30%。
France's lockdown has taken countless cars and delivery trucks off the roads since coming into effect on March 17, and massively reduced the number of flights at the two airports serving the capital.
自3月17日实施以来，法国的封锁已使无数汽车和货运卡车无法上路，并大幅减少了巴黎两个机场的航班数量。
The Airparif report said that just two days after the self-confinement began, it registered 'a 20 to 30 percent improvement in air quality in the Paris metropolis, after nitrogen oxide emissions dropped by more than 60 percent.'
巴黎大区空气质量监测协会的报告称，在居家措施实施仅两天后，“巴黎大都会地区的空气质量改善了20%到30%，氮氧化物的排放量下降了超过60%。”
The European Environment Agency’s (EEA) data has confirmed a large decrease in air pollutant concentrations - in particular of nitrogen dioxide (NO2).
欧洲环境署的数据证实了空气污染物浓度的大幅下降，尤其是二氧化氮。
NASA satellite images have already revealed dramatic reductions in concentrations of nitrogen dioxide in China and northern Italy, coinciding with lockdowns there.
美国国家航空航天局的卫星图像显示，在各国实施封锁期间，中国和意大利北部的二氧化氮浓度大幅下降。
Other footage from the European Space Agency Copernicus satellite reveals a 'notable drop' in air pollution over Italy after the coronavirus lockdown.
欧洲航天局哥白尼卫星拍摄的画面显示，在因新冠疫情实施封锁后，意大利上空的空气污染水平“显著下降”。
英文来源：每日邮报
翻译&编辑：yaning
