Air Quality Before and After COVID-19 Lockdown Phases Around New Delhi, India.

IF 2.4 Q1 Medicine
Journal of Health and Pollution Pub Date : 2021-05-28 eCollection Date: 2021-06-01 DOI:10.5696/2156-9614-11.30.210602
Sudesh Chaudhary, Sushil Kumar, Rimpi Antil, Sudesh Yadav
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引用次数: 4

Abstract

Background: The COVID-19 pandemic has had a deep global impact, not only from a social and economic perspective, but also with regard to human health and the environment. To restrict transmission of the virus, the Indian government enforced a complete nationwide lockdown except for essential services and supplies in phases from 25 March to 31 May 2020. Ambient air quality in and around New Delhi, one of the most polluted cities of world, was also impacted during this period.

Objective: The aim of the present study was to assess and understand the impact of four different lockdown phases (LD1, LD2, LD3 and LD4) on five air pollutants (particulate matter (PM) PM2.5, PM10, nitrogen oxide (NOx), sulfur dioxide (SO2) and ozone (O3)) compared to before lockdown (BLD) at 13 air monitoring stations in and around New Delhi.

Methods: Secondary data on five criteria pollutants for 13 monitoring stations in and around New Delhi for the period 1 March to 31 May 2020 was accessed from the Central Pollution Control Bard, New Delhi. Data were statistically analyzed across lockdown phases, meteorological variables, and prevailing air sources around the monitoring stations.

Results: Pollutant concentrations decreased during LD1 compared to BLD except for O3 at all stations. PM2.5 and PM10 remained either close to or higher than the National Ambient Air Quality Standards (NAAQS) due to prevailing high-speed winds. During lockdown phases, NO2 decreased, whereas O3 consistently increased at all stations. This was a paradoxical situation as O3 is formed via photochemical reactions among NOx and volatile organic compounds. Principal component analysis (PCA) extracted two principal components (PC1 and PC2) which explained up to 80% of cumulative variance in data. PM2.5, PM10 and NO2 were associated with PC1, whereas PC2 had loadings of either O3 only or O3 and SO2 depending upon monitoring station.

Conclusions: The present study found that air pollutants decreased during lockdown phases, but these decreases were specific to the site(s) and pollutant(s). The decrease in pollutant concentrations during lockdown could not be attributed completely to lockdown conditions as the planetary boundary layer increased two-fold during lockdown compared to the BLD phase. Such restrictions could be applied in the future to control air pollution but should be approached with caution.

Competing interests: The authors declare no competing financial interests.

Abstract Image

Abstract Image

印度新德里新冠肺炎封锁前后的空气质量。
背景:新冠肺炎大流行不仅从社会和经济角度,而且从人类健康和环境角度,对全球产生了深刻影响。为了限制病毒的传播,印度政府从2020年3月25日至5月31日分阶段在全国范围内实施了全面封锁,但基本服务和用品除外。新德里是世界上污染最严重的城市之一,其周围的环境空气质量在此期间也受到了影响。目的:本研究旨在评估和了解四个不同封锁阶段(LD1、LD2、LD3和LD4)对五种空气污染物(颗粒物(PM)PM2.5、PM10、氮氧化物(NOx),二氧化硫(SO2)和臭氧(O3))。方法:从新德里中央污染控制局获取2020年3月1日至5月31日期间新德里及其周围13个监测站的五种标准污染物的二次数据。对封锁阶段、气象变量和监测站周围主要空气源的数据进行了统计分析。结果:除O3外,LD1期间所有站点的污染物浓度均低于BLD。由于盛行高速风,PM2.5和PM10仍接近或高于国家环境空气质量标准(NAAQS)。在封锁阶段,NO2减少,而O3在所有站点持续增加。这是一种矛盾的情况,因为O3是通过NOx和挥发性有机化合物之间的光化学反应形成的。主成分分析(PCA)提取了两个主成分(PC1和PC2),解释了数据中高达80%的累积方差。PM2.5、PM10和NO2与PC1有关,而PC2的负荷仅为O3或O3和SO2,具体取决于监测站。结论:本研究发现,空气污染物在封锁阶段减少,但这些减少是特定于现场和污染物的。封锁期间污染物浓度的下降不能完全归因于封锁条件,因为与BLD阶段相比,行星边界层在封锁期间增加了两倍。这些限制措施将来可以用于控制空气污染,但应谨慎对待。竞争性利益:作者声明没有竞争性经济利益。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Journal of Health and Pollution
Journal of Health and Pollution Medicine-Public Health, Environmental and Occupational Health
自引率
0.00%
发文量
0
审稿时长
18 weeks
期刊介绍: The Journal of Health and Pollution (JH&P) was initiated with funding from the European Union and World Bank and continues to be a Platinum Open Access Journal. There are no publication or viewing charges. That is, there are no charges to readers or authors. Upon peer-review and acceptance, all articles are made available online. The high-ranking editorial board is comprised of active members who participate in JH&P submissions and editorial policies. The Journal of Health and Pollution welcomes manuscripts based on original research as well as findings from re-interpretation and examination of existing data. JH&P focuses on point source pollution, related health impacts, environmental control and remediation technology. JH&P also has an interest in ambient and indoor pollution. Pollutants of particular interest include heavy metals, pesticides, radionuclides, dioxins, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), air particulates (PM10 and PM2.5), and other severe and persistent toxins. JH&P emphasizes work relating directly to low and middle-income countries, however relevant work relating to high-income countries will be considered on a case-by-case basis.
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