College of Management, Shenzhen University, Shenzhen, 518060, Guangdong, China.
Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
Sci Rep. 2021 Oct 13;11(1):20339. doi: 10.1038/s41598-021-99546-9.
This study investigated the environmental spatial heterogeneity of novel coronavirus (COVID-19) and spatial and temporal changes among the top-20 metropolitan cities of the Asia-Pacific. Remote sensing-based assessment is performed to analyze before and during the lockdown amid COVID-19 lockdown in the cities. Air pollution and mobility data of each city (Bangkok, Beijing, Busan, Dhaka, Delhi, Ho Chi Minh, Hong Kong, Karachi, Mumbai, Seoul, Shanghai, Singapore, Tokyo, Wuhan, and few others) have been collected and analyzed for 2019 and 2020. Results indicated that almost every city was impacted positively regarding environmental emissions and visible reduction were found in Aerosol Optical Depth (AOD), sulfur dioxide (SO), carbon monoxide (CO), and nitrogen dioxide (NO) concentrations before and during lockdown periods of 2020 as compared to those of 2019. The highest NO emission reduction (~ 50%) was recorded in Wuhan city during the lockdown of 2020. AOD was highest in Beijing and lowest in Colombo (< 10%). Overall, 90% movement was reduced till mid-April, 2020. A 98% reduction in mobility was recorded in Delhi, Seoul, and Wuhan. This analysis suggests that smart mobility and partial shutdown policies could be developed to reduce environmental pollutions in the region. Wuhan city is one of the benchmarks and can be replicated for the rest of the Asian cities wherever applicable.
本研究调查了新型冠状病毒（COVID-19）的环境空间异质性以及亚太地区前 20 大都市的时空变化。采用基于遥感的评估方法分析了这些城市在 COVID-19 封锁期间前后的情况。收集和分析了每个城市（曼谷、北京、釜山、达卡、德里、胡志明市、香港、卡拉奇、孟买、首尔、上海、新加坡、东京、武汉等）的空气污染和流动性数据，分别对 2019 年和 2020 年的数据进行了分析。结果表明，几乎所有城市的环境排放都受到了积极影响，与 2019 年相比，2020 年封锁期间的气溶胶光学深度（AOD）、二氧化硫（SO）、一氧化碳（CO）和二氧化氮（NO）浓度明显降低。在 2020 年的封锁期间，武汉的 NO 排放量降幅最大（约 50%）。北京的 AOD 最高，科伦坡的 AOD 最低（< 10%）。总体而言，2020 年 4 月中旬之前，移动减少了 90%。德里、首尔和武汉的移动减少了 98%。这项分析表明，智能移动和部分关闭政策的制定可以减少该地区的环境污染。武汉是一个基准城市，可以在适用于亚洲其他城市的情况下进行复制。
