Abstract
As the main source of dust in Asia, China often suffers from dust events. The temporal and spatial characteristics of dust events change with the variations of geography, climate and human activities. Based on the criteria of selecting dust events proposed recently by the China Environmental Monitoring Station, the hourly concentration of PM10 and PM2.5 of 336 cities in China from 2015 to 2020 were used to study the temporal and spatial characteristics of dust events more accurately and objectively. The results showed that all of the dust events in China clearly decreased, but the strong dust events did not decrease. There were 334 cities that had dust events except Shenzhen and Dongguan, 299 cities were seriously polluted due to dust events, 134 cities encountered dust level III and 56 cities encountered dust level IV. The high frequencies of dust events were mainly distributed in Northern China, especially in Northwest China. The dust contribution of PM10 to the cities in Northwest China was more than 10% and about 5–10% for PM2.5. The most likely month for dust was May. The starting time of dust was bimodally distributed, and the most common starting time was 10:00–11:00 BJT, followed by 22:00–23:00 BJT. According to the PSCF (Potential Source Contribution Function) results, the dust potential source contribution of different cities mainly came from the northwest, and was mainly affected by Mongolia in addition to the local dust in China. In addition, Beijing was obviously affected by dust recirculation. This study is of great significance to the improvement of the forecast of dust weather and the warning of heavy pollution caused by dust events.
Highlights
IntroductionThe dust emission capacity of Taklimakan Desert is the highest in East Asia, and the emission in spring is about
Due to the existence of Taklimakan Desert, Gobi Desert, Badain Jaran Desert, TenggerDesert and other deserts, dust events often affect China
PM10 is greater than 1000 μg·m−3 frequently when strong dust events occur, and may even exceed 2000 μg·m−3 .the dust events were classified into four levels according to
Summary
The dust emission capacity of Taklimakan Desert is the highest in East Asia, and the emission in spring is about. 70.54 Tg/yr, accounting for 42% of the total dust emission in East Asia [1]. A dust event has a direct impact on human activity and life and affects human health. 2021 [8] found that all pollutants, such as total suspended particulates (TSP), SO2 and NO2 , were increased on strong dust storm days, as compared to normal days. 2018 [10] found strong territory pollution with aerosols during sandstorms by studying a severe dust storm that occurred in Northwest China during
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