Abstract:

In January and July, 2018, the mobile monitoring method was used to collect dust particles from Wuhai, Inner Mongolia. Together with data from the monitoring station, the temporospatial distribution pattern and influencing factors of dust concentration for different particle sizes were studied. The results show that the dust pollution level is much higher in spring and winter than in summer and autumn, with the highest level in spring and relatively low level in summer. The worst month for PM_2.5 pollution March and for PM₁₀ is April. The daily dust concentration peaks between 10-noon and drops to the lowest level between 4:00-6:00 in the afternoon. Areas with high dust concentration are distributed in strips in the east while spread out radially from point sources in the central, south and west. Dust concentration in the industrial, mining and urban areas is higher than in forest and unused lands, while arable land and water body have the lowest dust level. In Wuhai City, the industrial and mining lands are the main source of coarse particulate, while the urban area is the main source of summer fine dust. Water bodies and arable and forest lands can significantly reduce the concentration of airborne particulates. The total suspended particulate(TSP)and individual particulate concentration are positively correlated with wind speed and humidity and negatively correlated with temperature and altitude. Among the influencing factors, air pressure is the most important one affecting TSP concentration, while humidity affects PM_1-10 concentrations the most. The dust particle concentration for different particle sizes is constrained by multiple factors, such as normalization index, meteorology and topography, whereas a single condition has only limited impact on atmospheric dust.

Key words: dust concentration, temporal and spatial distribution, influence factor, land use