Spatial-temporal Distribution Characteristics of PM_2.5 and PM₁₀ in the Northeast Tibetan Plateau and the Influence of Meteorological Factors

With the rapid development of industrialization, the problem of air pollution can not be ignored. As an important ecological security strategic area in China, the Northeast Tibetan Plateau had prominent particulate pollution caused by soil desertification. Based on the monthly concentrations of inhalable particulate matter (PM₁₀) and fine particulate matter (PM_2.5) in 8 cities (prefectures) from 2015 to 2019 and the meteorological data, this study analyzed the spatial-temporal distribution characteristics of PM_2.5 and PM₁₀, the relationships between them and meteorological factors (precipitation, temperature and wind speed) and the degree of influence of meteorological factors. The results showed that: ①Xining city, Haidong city and Huangnan prefecture, which were densely populated and economically developed in the east of Qinghai province, had higher PM_2.5 and PM₁₀ concentrations, with an average level of 44.2 μg/m³ (99.1 μg/m³)、44.7 μg/m³ (99.7 μg/m³) and 36.5 μg/m³ (72.2 μg/m³) respectively. In terms of time distribution, the concentration of particulate matter in each region showed a downward trend year by year. The spatial distribution showed that PM_2.5 gradually increased from the west to the east, and PM₁₀ was high in the east and low in the west. ② The peak values of temperature and precipitation appeared in summer, showing a "Λ" distribution law. While the monthly concentration changes of PM_2.5 and PM₁₀ in various regions showed a "V" distribution law. The particle concentration in non-heating season was the lowest and that in heating season was the highest. ③ Among the effects of various meteorological factors, the concentrations of PM_2.5 and PM₁₀ were strongly or moderately negatively correlated with precipitation and temperature, and were negatively affected by temperature. The concentration of particulate matter was negatively correlated with wind speed. The concentration of PM_2.5 was negatively affected by wind speed, while the concentration of PM₁₀ was significantly positively affected by wind speed, indicating that wind-induced dust had a prominent contribution to air pollution, but the action mechanism between wind speed and pollutant concentration was complex. The results of this study could provide reference and theoretical basis for the improvement and prediction of air quality in typical regions.