Faculty of Civil Engineering, Institute of Technology, Shri Ramswaroop Memorial University, Barabanki, 225003, UP, India.
Department of Geology, V.O. Chidambaram College, Tuticorin, Tamil Nadu, India.
Environ Res. 2022 Mar;204(Pt B):112107. doi: 10.1016/j.envres.2021.112107. Epub 2021 Sep 22.
The COVID-19 pandemic lockdown supposedly provided a 'window' of reinstatement to natural resources including the air quality, but the scenario after the phased unlocking is yet to be explored. Consequently, here we evaluated the status of air quality during the 8th phase of unlocking of COVID-19 lockdown (January 2021) at three locations of North India. The first site (S1) was located at Punjab Agricultural University, Ludhiana-PPCB; the second site (S2) at Yamunapuram, Bulandshahr-UPPCB; and the third site (S3) at Okhla Phase-2, Delhi-DPCC. The levels of PM2.5 showed a significant increase of 525.2%, 281.2%, and 185.0% at sites S1, S2 and S3, respectively in the unlock 8 (January 2021), in comparison to its concentration in the lockdown phase. Coherently, the levels of PM10 also showed a prominent increase of 284.5%, 189.1%, and 103.9% at sites S3, S1, and S2, respectively during the unlock 8 as compared to its concentration in the lockdown phase. This rise in the concentration of PM2.5 and PM10 could be primarily attributed to the use of biomass fuel, industrial and vehicular emissions, stubble burning considering the agricultural activities at sites S1 and S2. Site S3 is a major industrial hub and has the highest population density among all three sites. Consequently, the maximum increase (295.7%) in the NO levels during the unlock 8 was witnessed at site S3. The strong correlation between PM2.5, PM10, and CO, along with the PM2.5/PM10 ratio confirmed the similar origin of these pollutants at all the three sites. The improvements in the levels of air quality during the COVID-19 lockdown were major overtaken during the various phases of unlocking consequent to the initiation of anthropogenic processes.
新冠疫情封锁期间，据称自然环境（包括空气质量）得到了一定程度的恢复，但解封后的情况仍有待探索。因此，本研究评估了印度北部三个地区在第 8 阶段（2021 年 1 月）解封期间的空气质量状况。第一个地点（S1）位于旁遮普农业大学，Ludhiana-PPCB；第二个地点（S2）位于Yamunapuram，Bulandshahr-UPPCB；第三个地点（S3）位于Okhla 二期，Delhi-DPCC。与封锁期相比，解锁 8 期（2021 年 1 月）时，S1、S2 和 S3 站点的 PM2.5 水平分别显著增加了 525.2%、281.2%和 185.0%。相应地，PM10 水平也分别显著增加了 284.5%、189.1%和 103.9%。这可能主要归因于生物质燃料的使用、工业和车辆排放、考虑到 S1 和 S2 站点农业活动的秸秆燃烧。S3 站点是一个主要的工业中心，也是三个站点中人口密度最高的地区。因此，在解锁 8 期，NO 水平的最大增幅（295.7%）出现在 S3 站点。PM2.5、PM10 和 CO 之间的强相关性以及 PM2.5/PM10 比值证实了所有三个站点这些污染物的相似来源。在新冠疫情封锁期间，空气质量水平有所改善，但在随后的解封阶段，由于人为活动的开始，这些改善被大大超过。
