Biswal Akash, Singh Tanbir, Singh Vikas, Ravindra Khaiwal, Mor Suman
Department of Environment Studies, Panjab University, Chandigarh, 160014, India.
National Atmospheric Research Laboratory, Gadanki, 517502, India.
Heliyon. 2020 Sep;6(9):e04764. doi: 10.1016/j.heliyon.2020.e04764. Epub 2020 Aug 21.
The World Health Organization has declared the COVID-19 pandemic a global public health emergency. Many countries of the world, including India, closed their borders and imposed a nationwide lockdown. In India, the lockdown was declared on March 24 for 21 days (March 25-April 14, 2020) and was later extended until May 3, 2020. During the lockdown, all major anthropogenic activities, which contribute to atmospheric pollution (such as industries, vehicles, and businesses), were restricted. The current study examines the impact of the lockdown on tropospheric NO concentrations. Satellite-based ozone monitoring instrument sensor data were analyzed in order to investigate the variations in tropospheric NO concentrations. The results showed that from March 1 to 21, 2020, the average tropospheric NO concentration was 214.4 ×10 molecule cm over India, and it subsequently decreased by 12.1% over the next four weeks. An increase of 0.8% in tropospheric NO concentrations was observed for the same period in 2019 and hence, the reduced tropospheric NO concentrations can be attributed to restricted anthropogenic activities during the lockdown. In the absence of significant activities, the contribution of various sources was estimated, and the emissions from biomass burning were identified as a major source of tropospheric NO during the lockdown. The findings of this study provide an opportunity to understand the mechanism of tropospheric NO emissions over India, in order to improve air quality modeling and management strategies.
世界卫生组织已宣布新型冠状病毒肺炎疫情为全球突发公共卫生事件。包括印度在内的世界许多国家都关闭了边境并实施了全国范围的封锁。在印度，3月24日宣布封锁21天（2020年3月25日至4月14日），后来延长至2020年5月3日。在封锁期间，所有导致大气污染的主要人为活动（如工业、车辆和商业活动）都受到了限制。本研究考察了封锁对对流层一氧化氮浓度的影响。为了研究对流层一氧化氮浓度的变化，对基于卫星的臭氧监测仪器传感器数据进行了分析。结果表明，2020年3月1日至21日，印度上空对流层一氧化氮的平均浓度为214.4×10分子/立方厘米，在接下来的四周内下降了12.1%。2019年同期对流层一氧化氮浓度上升了0.8%，因此，对流层一氧化氮浓度的降低可归因于封锁期间人为活动受限。在没有重大活动的情况下，对各种来源的贡献进行了估算，生物质燃烧排放被确定为封锁期间对流层一氧化氮的主要来源。本研究结果为了解印度对流层一氧化氮排放机制提供了契机，以便改进空气质量建模和管理策略。
