Assessment of air quality before and during the COVID-19 and its potential health impacts in an arid oasis city: Urumqi, China

Abstract

As a key node city of the “Silk Road Economic Belt” Urumqi has been listed as one of the ten most polluted cities in the world, posing a serious threat to the urban environment and residents' health. This study analyzed the air quality before and during the COVID-19 (Coronavirus disease 2019) pandemic and its potential health effects based on the data of PM 2.5 , PM 10 , SO 2 , NO 2 , CO, and O 3 _8h levels from 10 air quality monitoring stations in Urumqi from January 1, 2017, to December 31, 2021. As per the results, the concentrations of the air pollutants PM 2.5 , PM 10 , SO 2 , NO 2 , CO, and O 3 _8h in Urumqi from 2017 to 2021 showed a cyclical trend, and the implementation of COVID-19 prevention and control measures could effectively reduce the concentration(ρ) of air pollutants. The mean value of ρ(PM 2.5 ) decreased from 2017 to 2021, whereas ρ(O 3 _8h) showed a waveform change trend (increased in 2017–2018, decreased in 2018–2020, and increased after 2020). Meanwhile, the maximum annual average values of ρ(PM 2.5 ) and ρ(O 3 _8h) for the six monitoring stations during 2017–2021 occurred at sites S2 (74.37 µg m −3 ) and S6 (91.80 µg m −3 ), respectively; rapid industrialization had a greater impact on PM 2.5 and O 3 _8h concentrations compared to commercial and residential areas. In addition, the air quality index data series can characterize the fluctuation trend of PM 2.5 . The high pollution levels (Class IV and V) of the air pollutants PM 2.5 and O 3 _8h in Urumqi have been decreasing annually, and good days can account for 80–95% of the total number of days in the year, indicating that the number of days with a potential threat to residents' health is gradually decreasing. Therefore, more attention should be paid in controlling and managing air pollution in Urumqi.

Spatiotemporal changes in fine particulate matter and ozone in the oasis city of Korla, northeastern Tarim Basin of China

“…The highest concentration of 63.8 ± 2.2µg m −3 was observed in spring at station S2, while the lowest value of 23.4 ± 0.6 µg m −3 occurred in summer at station S3. However, pollutant emissions resulting from energy consumption during industrial production in industrial areas contribute more to PM 2.5 than residential and motorized trips 4 .…”

“…Air pollution is a pressing global environmental concern that has significant impacts on atmospheric visibility, local climate, and the physical and mental health of human beings 1 , 2 . Air pollution is defined as a condition in which the concentration of specific substances in the air exceeds a certain threshold over a certain period, causing harm to humans or ecosystems 3 , 4 . Even brief exposure to air pollution raises a noteworthy risk to human health, exacerbating the Global Burden of Disease (GBD) and ultimately contributing to hospitalization and mortality rates 3 , 5 , 6 .…”

“…PM can penetrate the human body by respiration and settle in the lungs, posing a threat to human health 13 . The 2018 Environmental Performance Index [EPI] shows that the environmental quality of China ranked fourth, including PM 2.5 14 , China's PM 2.5 concentrations tend to be well above the National Ambient Air Quality Standards (GB3095-2012 Level 2), which is equivalent to the WHO Interim Target I [IT-1] 4 .…”