Abstract

Air Pollution plagues urbanised areas and enhances mankind’s vulnerability to the COVID-19 virus.

Background: According to W.H.O, Kolkata (India) ranks 25^th amongst 1100 cities in the world. Curbs on movement reduced this pollution during COVID-19 lockdown. Resumption of activities nullified this.

Objectives: This study analyses the trend of air pollutants, their interrelationships with PM_2.5, PM₁₀, resultant National Air Quality Indices (NAQIs) before and after COVID-19 lockdowns in Kolkata.

Methods: Temporal trend analysis, PCA, multiple regressions and NAQIs were computed using pollutant data.

Results: SO₂, NO₂, CO, NH₃, PM₁₀ and PM_2.5 witnessed drastic falls and rise through the pre-lockdown to lockdown and unlock phases, respectively. NAQIs reduced by 74.55%, in the former phase, while in the next it reduced by 5.93%. PM₁₀ and PM_2.5, <5µm in aerodynamic diameter, had positive associations with SO₂ and NO₂, which stimulates air-borne transmission of COVID-19.

Conclusion: Pollutant monitoring, bio-filtration, biofuel use may be adopted.

摘要

空气污染困扰着城市化地区，并增加了人类对 COVID-19 病毒的脆弱性。

背景：据世界卫生组织统计，加尔各答（印度）在全球 1100 个城市中排名^第25^位。在COVID-19锁定期间，运动的路缘石减少了这种污染。恢复活动使这一点无效。

目标：本研究分析了加尔各答 COVID-19 封锁前后空气污染物的趋势、它们与 PM _2.5、 PM ₁₀以及由此产生的国家空气质量指数 (NAQI)的相互关系。

方法：使用污染物数据计算时间趋势分析、PCA、多元回归和 NAQI。

结果：SO ₂、NO ₂、CO、NH ₃、PM ₁₀和PM _{2.5 分别}经历了锁定前到锁定和解锁阶段的急剧下降和上升。前一阶段NAQI下降74.55%，下一阶段下降5.93%。PM ₁₀和 PM _{2.5 的}空气动力学直径小于 5µm，与 SO ₂和 NO ₂呈正相关，刺激 COVID-19 的空气传播。

结论：可采用污染物监测、生物过滤、生物燃料使用。