Thomas Jobin, Jainet P J, Sudheer K P
Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, 600 036, India.
KSCSTE-Centre for Water Resources Development and Management, Kozhikode, 673 571, Kerala, India.
Anthropocene. 2020 Dec;32:100270. doi: 10.1016/j.ancene.2020.100270. Epub 2020 Nov 28.
This study assesses the effect of lockdown, due to the coronavirus disease (COVID-19) pandemic, on the concentration of different air pollutants and overall air quality of a less industrialized region (Kerala) of India. We analysed data from four ambient air quality stations over three years (January to May, 2018-2020) with pairwise comparisons, trend analysis, etc. Results indicated unprecedented reduction in the concentration of the air pollutants: nitrogen dioxide, NO (-48 %), oxides of nitrogen, NO (-53 % to -90 %), carbon monoxide, CO (-24 % to -67 %) and the particulate matter (-24 % to -47 % for particulate matter with a diameter of less than 2.5 μm, PM; -17 % to -20 % for particulate matter with a diameter of less than 10 μm, PM), as well as the reduction of the National Air Quality Index (NAQI). These reductions indicate an overall improvement of the ambient air quality due to restrictions on transportation, construction, and the industrial sectors during lockdown, even in an area considered less industrial. Despite the general decreasing trend of the concentration of various air pollutants from January to May, suggesting seasonal influences, the trend was intensified in the year 2020 due to the added effect of the lockdown measures. Comparison of the results with those from larger and more industrialized cities suggests that the effects of lockdown are more variable, and focused on the levels of gaseous pollutants. Findings from this study demonstrate the far-reaching effects and implications of the COVID-19 lockdown on ambient air quality, even on less industrialized and less urbanized regions.
本研究评估了因冠状病毒病（COVID-19）大流行实施的封锁措施对印度一个工业化程度较低地区（喀拉拉邦）不同空气污染物浓度和整体空气质量的影响。我们分析了四个环境空气质量监测站三年（2018年1月至2020年5月）的数据，并进行了成对比较、趋势分析等。结果表明，空气污染物浓度出现了前所未有的下降：二氧化氮（NO）下降了48%，氮氧化物（NO）下降了53%至90%，一氧化碳（CO）下降了24%至67%，颗粒物（直径小于2.5μm的颗粒物，即PM2.5，下降了24%至47%；直径小于10μm的颗粒物，即PM10，下降了17%至20%），同时国家空气质量指数（NAQI）也有所下降。这些下降表明，即使在一个工业化程度较低的地区，封锁期间对交通、建筑和工业部门的限制也使环境空气质量总体得到了改善。尽管从1月到5月各种空气污染物浓度总体呈下降趋势，显示出季节性影响，但由于封锁措施的叠加效应，2020年这一趋势有所加剧。将结果与更大、工业化程度更高的城市的结果进行比较表明，封锁的影响更具差异性，且主要集中在气态污染物水平上。本研究结果表明，COVID-19封锁措施对环境空气质量产生了深远影响，即使是在工业化程度较低和城市化程度较低的地区。
