Impact of Meteorological Conditions and Human Activities on Air Quality During the COVID-19 Lockdown in Northeast China

Abstract

During the lockdown implemented to curb the spread of COVID-19, human activities have drastically reduced, providing a valuable opportunity to study and compare the impact of meteorological conditions and human activities on air quality. In this study, large-scale weather circulation, local meteorological conditions, and the impact of human activities are comprehensively considered, and changes in the concentration of major air pollutants in the northeast during this period are systematically studied. The large-scale weather circulation patterns that mainly affect the northeast region are divided into nine types by using the T-mode Principal components analysis objective circulation classification method. It is found that the northeast region is located at the edge of weak high pressure (Types 1, 2, and 7) and at the rear of high pressure (Type 4) and has higher concentrations of PM2.5, NO2, SO2, and CO; in cyclonic weather systems, low vortices (Types 3 and 5) and under the influence of the updraft (Type 6) in front of the trough, the ozone concentration is higher. The changes in the concentrations of PM2.5, NO2, CO, SO2, and O3 in the three cities, namely Shenyang, Changchun, and Harbin, during the lockdown period are compared, and it is found that the concentrations of PM2.5, NO2, CO, and SO2 have a tendency to first decrease and then increase, while the changes of O3 concentration are cyclical and increased significantly during this period. This demonstrates that pollutants such as PM2.5, NO2, CO, and SO2 are more susceptible to human activities and local meteorological conditions, and changes in O3 concentration are more closely related to changes in weather circulation types. Finally, the FLEXPART-WRF model is used to simulate the pollution process of nine circulation types, which confirms that particulate pollution in the northeast is mainly affected by local emissions and local westward sinking airflow.

Analysis of air quality changes and causes in the Liaoning region from 2017 to 2022

“…Although the lower height of the boundary layer at night is not conducive to the dispersion of air pollutants, fewer emissions from sources still result in lower nighttime concentrations of air pollutants. It can be seen that governmental prevention and control measures, as well as environmental protection and emission reduction measures, can change the daily change patterns of particulate pollutants, which is consistent with the findings of Cui Zhihao and Wang Aiping (CUI et al, 2021;WANG et al, 2021). Comparison of concentration distribution of various pollutants in Liaoning Province in 2017~2019 and 2020~2022.…”

“…SO 2 and NO 2 are the primary pollutants originating from coal combustion and industry. SO 2 is primarily generated from the exhaust gases of chemical and sulfuric acid plants, and NO x is generated from automobile exhaust and nitric acid production plants (SU et al, 2012;Li et al, 2019;WANG et al, 2021). NO 2 , as a representative pollutant of traditional photochemical smog, has a critical conversion function in Under relatively stable air pollution emission sources, the variation of EMI index and PM 2.5 concentration is mainly determined by meteorological conditions.…”

Green production information transparency and online purchase behavior: Evidence from green agricultural products in China

“…Nevertheless, studies in this area are largely scattered and research on sustainable development and environmental protection in agriculture is still in its infancy. The COVID-19 epidemic increased public concerns about health and environment (He et al, 2022;Singh et al, 2022;Wang et al, 2022), thereby the consumers' willingness to buy green or environmentally friendly products has grown rapidly in both developed and developing countries (Kumar et al, 2021;Chen et al, 2022). The COVID-19 pandemic developed new challenges for global consumers by leading to online shopping (Al Halbusi et al, 2022).…”

Forecast of Fine Particles in Chengdu under Autumn–Winter Synoptic Conditions

“…The boundary layer structures associated with fine particle pollution differ among weather patterns [ 12 ]; thus, objective weather classification can be used to study both fine particle and ozone control. For example, in northeast China and the Poyang and Dongting Lakes areas, ozone pollution is dominated by weather patterns, whereas fine particles are mainly controlled by human activities [ 13 , 14 ]. Fine particle concentrations differ from ozone concentrations under identical weather patterns [ 15 ].…”