Abstract:

Based on the monitoring data of ambient air quality in Shaanxi province from 2016 to 2020， the characteristics of dust events and their influence on air quality in Shaanxi province were analyzed. The results show that： （1） The dust events in Shaanxi province occurs 9-19 times a year， and the dust impact days are 20-46 days a year； Dust events mainly occurs in spring， with high incidence in May and March； The spatial distribution of dust events frequency decreases from north to south and from east to west. （2） The duration of the dust influence process in the cities ranges from 2 to 120 hours， and the duration in cities in Guanzhong is generally longer than that in northern Shaanxi and southern Shaanxi； The peak concentration of PM₁₀ varies widely in different dust influence processes， and the highest value appears in Yulin （3 219 μg·m^-3）. （3） Dust events has the greatest impact on the annual average concentration of PM₁₀ in Shaanxi province in 2018 and the smallest in 2020， with the absolute contribution of annual average concentration of 9.3 μg·m^-3 and 2.9 μg·m^-3， respectively. The proportion of exceeding ambient air quality standards of dust impact days in the cities is between 66.7% and 89.7%， and the pollution level is mainly light pollution and moderate pollution， with less serious pollution and severe pollution. All of the severe pollution in Yulin， Yan'an and Shangluo comes from the influence of dust events， and 20.5%-66.7% of the serious pollution in 5 cities in Guanzhong comes from the influence of dust events.

Key words: dust events, Shaanxi province, air quality, PM₁₀