Department of Civil and Environmental Engineering, Louisiana State University, Baton Rouge, LA, 70803, USA.
Department of Civil Engineering, Indian Institute of Technology Guwahati, 781039, India.
Chemosphere. 2019 Jun;225:27-34. doi: 10.1016/j.chemosphere.2019.02.154. Epub 2019 Feb 26.
Severe air pollution events were observed frequently in north India in recent years especially at its capital, Delhi. Criteria air pollutants data at 10 sites for 2017 in Delhi were analyzed. The results show annual fine particulate matter (PM) concentrations exceeded the National Ambient Air Quality Standards (NAAQS) of 60 μg/m at all sites from 105.51 (site 10) to 143.23 μg/m (site 7). Sub-urban sites (site 8, 9 and 10) had lower PM concentrations than urban sites. Coarse PM (PM) and ozone (O) were also important with annual averages of 399.56 μg/m and 75.69 ppb, respectively. Peak PM occurred at the Diwali in early November and Christmas. Only PM showed a significant weekly difference with a weekdays/weekends ratio of ∼1.5. PM/PM ratio in episode days with PM of >60 μg/m was higher than non-episode days. Pearson correlation coefficients show O was negatively related with CO, SO, and NO, while PM was positively related to these pollutants. Analysis of two extreme events from Nov. 6th to Nov. 14th and Dec. 18th to Dec. 26th shows that meteorological conditions with low wind speed and warm temperature kept PM concentrations at a high level during these events. Backward trajectory and cluster analysis show the wind coming from northwest of Delhi, where massive anthropogenic emissions were generated, led to high concentrations of air pollutants to Delhi. Health risk analysis reveals that PM and PM were the two major pollutants threatening public health among the six criteria pollutants.
近年来，印度北部频繁出现严重的空气污染事件，尤其是其首都德里。分析了德里 2017 年 10 个地点的 10 项标准空气污染物数据。结果表明，所有地点的年细颗粒物（PM）浓度均超过国家环境空气质量标准（NAAQS）的 60μg/m，从 105.51μg/m（地点 10）到 143.23μg/m（地点 7）。郊区站点（站点 8、9 和 10）的 PM 浓度低于城市站点。粗颗粒物（PM）和臭氧（O）也很重要，年平均值分别为 399.56μg/m 和 75.69ppb。PM 的峰值出现在 11 月初的排灯节和圣诞节。只有 PM 显示出显著的周差异，工作日/周末比约为 1.5。PM 浓度>60μg/m 的事件日的 PM/PM 比值高于非事件日。Pearson 相关系数表明 O 与 CO、SO 和 NO 呈负相关，而 PM 与这些污染物呈正相关。对 11 月 6 日至 11 月 14 日和 12 月 18 日至 12 月 26 日两次极端事件的分析表明，风速低、温度温暖的气象条件使这些事件期间 PM 浓度保持在较高水平。后向轨迹和聚类分析表明，来自德里西北部的风，那里产生了大量人为排放物，导致污染物浓度升高。健康风险分析显示，在六类污染物中，PM 和 PM 是威胁公众健康的两个主要污染物。
