Department of Environment Studies, Panjab University, Chandigarh, 160014, India.
Chandigarh Pollution Control Committee, Chandigarh, 160019, India.
Chemosphere. 2021 Jan;263:127978. doi: 10.1016/j.chemosphere.2020.127978. Epub 2020 Aug 18.
The variation in ambient air quality during COVID-19 lockdown was studied in Chandigarh, located in the Indo-Gangetic plain of India. Total 14 air pollutants, including particulate matter (PM, PM), trace gases (NO, NO, NO, SO, O, NH, CO) and VOC's (benzene, toluene, o-xylene, m,p-xylene, ethylbenzene) were examined along with meteorological parameters. The study duration was divided into four parts, i.e., a) 21 days of before lockdown b) 21 days of the first phase of lockdown c) 19 days of the second phase of lockdown d) 14 days of the third phase of lockdown. The results showed significant reductions during the first and second phases for all pollutants. However, concentrations increased during the third phase. The concentrations of SO, O and m,p-xylene kept on increasing throughout the study period, except for benzene, which continuously decreased. The percentage decrease in the concentrations during consecutive periods of lockdown were 28.8%, 23.4% and 1.1% for PM and 36.8%, 22.8% and 2.4% for PM respectively. The Principal Component Analysis (PCA) and characteristic ratios identified vehicular pollution as a primary source during different phases of lockdown. During the lockdown, residential sources showed a significant adverse impact on the air quality of the city. Regional atmospheric transfer of pollutants from coal-burning and stubble burning were identified as secondary sources of air pollution. The findings of the study offer the potential to plan air pollution reduction strategies in the extreme pollution episodes such as during crop residue burning period over Indo-Gangetic plain.
在印度恒河平原的昌迪加尔，研究了 COVID-19 封锁期间的环境空气质量变化。共检测了 14 种空气污染物，包括颗粒物（PM、PM）、痕量气体（NO、NO、NO、SO、O、NH、CO）和 VOC（苯、甲苯、邻二甲苯、间二甲苯、乙苯）以及气象参数。研究时间分为四个部分，即 a）封锁前 21 天；b）封锁第一阶段的 21 天；c）封锁第二阶段的 19 天；d）封锁第三阶段的 14 天。结果表明，在第一和第二阶段，所有污染物的浓度都显著降低。然而，在第三阶段，浓度增加。在整个研究期间，SO、O 和间二甲苯的浓度不断增加，除了苯，它一直在减少。在连续的封锁期间，浓度的百分比下降分别为 PM2.5 的 28.8%、23.4%和 1.1%，PM10 的 36.8%、22.8%和 2.4%。主成分分析（PCA）和特征比确定，在不同的封锁阶段，机动车污染是一个主要来源。在封锁期间，住宅来源对城市空气质量产生了重大不利影响。从燃煤和秸秆燃烧中识别出的污染物区域大气传输是空气污染的次要来源。这项研究的结果为在极端污染事件（如恒河平原作物残茬燃烧期间）制定减少空气污染的策略提供了潜力。
