COVID lockdowns significantly affect statewide atmospheric fine aerosols in India after excluding long-term pollution patterns and time-lag effect

IF 4.2 2区环境科学与生态学 Q2 ENVIRONMENTAL SCIENCES

Atmospheric Environment Pub Date : 2024-12-21 DOI:10.1016/j.atmosenv.2024.121013

Tunde O. Etchie , Ayotunde T. Etchie , Rachel T. Pinker , Prashant Kumar , Nedunchezhian Swaminathan

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引用次数: 0

Abstract

Atmospheric fine particulate matter (PM_2.5, near-surface concentrations when size is ≤ 2.5 μm) affects global climate and human health. India alone accounts for a quarter of the global PM_2.5-related health burden. Studies in India, mostly in urban areas, have reported significant declines in PM_2.5 concentrations because of COVID-19 lockdown. These studies did not consider the long-term PM_2.5 patterns and time-lag effect (inter-yearly variations in PM_2.5 concentrations carried forward from one period to another due to interannual shifts in meteorological conditions). Since the studies focused primarily on urban areas, not covering rural/remote areas where pollution may rise during lockdown, it is still unclear what impact lockdown had on statewide pollution levels in India. Here, we examine whether significant changes in fine-mode aerosol optical depth (AOD_f: columnar PM_2.5) occurred statewide across India because of lockdown after excluding the confounding variables. We found a substantial decrease in AOD_f in a few (28%) states/territories. The declines were significant (ANCOVA; α = 0.05) in some Northeastern states/territories: Sikkim (29%), Arunachal Pradesh (24%), Nagaland (5%), Mizoram (4%) and Uttarakhand (3%). However, in most states/territories, AOD_f increased significantly because of lockdown. The lockdown-associated hardship caused more people to rely on polluting cooking fuels, thereby increasing residential emissions, particularly in rural areas. At city-level, we found significant reductions in near-surface PM_2.5 concentrations due to lockdown. These declines were comparable or greater than previously reported. Also, there were significant reductions in AOD_f (PM_2.5 concentrations) at state (city) levels resulting from previous environmental intervention measures. If not accounted, previous environmental intervention measures can significantly bias lockdown effect estimates in India.

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来源期刊

Atmospheric Environment 环境科学-环境科学

CiteScore

9.40

自引率

8.00%

发文量

458

审稿时长

53 days

期刊介绍： Atmospheric Environment has an open access mirror journal Atmospheric Environment: X, sharing the same aims and scope, editorial team, submission system and rigorous peer review. Atmospheric Environment is the international journal for scientists in different disciplines related to atmospheric composition and its impacts. The journal publishes scientific articles with atmospheric relevance of emissions and depositions of gaseous and particulate compounds, chemical processes and physical effects in the atmosphere, as well as impacts of the changing atmospheric composition on human health, air quality, climate change, and ecosystems.