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Impact of COVID-19 on air quality in the Yangtze River Delta, China.
- Source :
- Environmental Monitoring & Assessment; Aug2021, Vol. 193 Issue 8, p1-13, 13p
- Publication Year :
- 2021
-
Abstract
- To investigate the effect of nationwide restrictions due to COVID-19 on air quality in the Yangtze River Delta (YRD), China, we defined four periods named period I (January 1 to 23, 2020), period II (January 24 to February 23), period III (February 24 to April 7), and period IV (April 8 to May 31), which indicated normal period, lockdown period, regional work resumption period, and nationwide work resumption period, respectively. Hourly PM<subscript>2.5</subscript>, PM<subscript>10</subscript>, NO<subscript>2</subscript>, SO<subscript>2</subscript>, CO, and O<subscript>3</subscript> in 41 cities in the YRD region were analyzed. Compared to period I, NO<subscript>2</subscript> decreased by 58% during period II and increased in periods III and IV. SO<subscript>2</subscript> remained constant during the four periods (7–8 μg/m<superscript>3</superscript>). Higher PM<subscript>2.5</subscript> concentration was monitored during period II (41 μg/m<superscript>3</superscript>) when compared to period III (35 μg/m<superscript>3</superscript>), which was resulted from the enhanced secondary formation. Spatial distribution analysis further indicated that PM<subscript>2.5</subscript> in the northern YRD during period II was higher than that during period III, whereas PM<subscript>2.5</subscript> in the southern YRD in the period II was similar to that in period III. The results demonstrated that PM<subscript>2.5</subscript> shows a nonlinear response to the reduction of its precursors, and this phenomenon varies in different areas. Compared to periods I (36 μg/m<superscript>3</superscript>) and III (64 μg/m<superscript>3</superscript>), relatively higher O<subscript>3</subscript> during period II (64 μg/m<superscript>3</superscript>) was probably resulted from less NO emission and hence weakened NO titration effect. The study suggested that coordinated and balanced measures are needed to improve air quality. [ABSTRACT FROM AUTHOR]
- Subjects :
- AIR quality
COVID-19
STAY-at-home orders
VOLUMETRIC analysis
Subjects
Details
- Language :
- English
- ISSN :
- 01676369
- Volume :
- 193
- Issue :
- 8
- Database :
- Complementary Index
- Journal :
- Environmental Monitoring & Assessment
- Publication Type :
- Academic Journal
- Accession number :
- 151976605
- Full Text :
- https://doi.org/10.1007/s10661-021-09342-1