研究称新德里再次成为全球污染最严重的首府城市

    New Delhi was the most polluted capital city last year, just like it was in 2018. That finding comes IQ AirVisual, a Swiss-based group that studies air-quality measurements from around the world.
    跟2018年一样,新德里去年再次成为全球污染最严重的首府城市。这一研究结果来自于IQ AirVisual,这是一家总部位于瑞士,研究世界各地空气质量测量值的组织。

    India was home to 21 of the world's 30 most polluted cities, the group reported.
    该组织报告称,全球污染最严重的30个城市有21个在印度。

    IQ AirVisual said the study measured levels of a kind of particulate matter (PM), called PM2.5, in major population centers.
    IQ AirVisual称这项研究统计了主要人口中心一种被称为PM2.5的颗粒物的水平。

    Researchers chose to examine PM2.5 because it "is the pollutant widely regarded as most harmful to human health," the report said.
    研究人员选择检查PM2.5,因为它“是一种被公认为对人体健康最有害的污染物。”

    These small particles, less than 2.5 microns in length, can go deep into the lungs. High PM2.5 levels can cause health problems, including cancer and heart disease, the report notes.
    这些长度小于2.5微米的小颗粒会深入到人体肺部。报告指出,PM2.5水平高会引发包括癌症和心脏病在内的健康问题。

    Researchers examined data about PM2.5 concentrations in the air. The information was collected hourly, from ground-based monitoring systems.
    研究人员检查了空气中的PM2.5浓度数据。这些信息通过地面检测系统每小时收集一次。

    In 2019, New Delhi's average yearly concentration of PM2.5 in a cubic meter of air was 98.6, the report said. That is more than twice the level of Beijing, which had an average of 42.1 during the year. Beijing was the ninth most polluted capital city, the study found.
    该报告称,2019年新德里每立方米空气中的PM2.5年均浓度为98.6。这是北京的两倍还要多,北京当年的平均水平为42.1。研究发现,北京在污染最严重的首都城市中排名第9位。

    New Delhi's harmful air has a number of causes. They include pollution from motor vehicles and industrial centers, dust from building projects and smoke from the burning of waste.
    新德里的有害空气存在多种原因。其中包括来自机动车辆和工业中心的污染,建筑项目产生的粉尘以及废物燃烧产生的烟雾。

    Late last year, rising air pollution levels forced Indian officials, who called the crisis a public health emergency, to close schools twice.
    去年年底,不断上升的空气污染水平迫使称这一危机是公共卫生紧急事态的印度官员两度下令学校停课。

    The study, however, said India did see "widespread improvements" in PM2.5 levels compared to 2018. These improvements were likely a result of better weather conditions, government cleanup efforts, and an overall economic slowdown.
    然而这项研究称印度的PM2.5水平与2018年相比确实得到了大范围改善。这些改善可能是由于天气状况改善,政府清理措施以及整体经济放缓所致。

    "Despite improvements, India still faces serious air pollution challenges," the report said.
    该报告称:“尽管有所改善,印度仍然面临着严重的空气污染挑战。”

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