Temporal and spatial distributions of particulate matters around mining areas under two coal mining methods in arid desert region of northwest China

The particulate matter (PM) in coal mining can bring pollution to the surrounding environment and have an adverse effect on human health. In order to prevent and control the PM pollution in coal mine and better understand the PM transportation in the air, spatial and temporal distribution of PM concentration in two typical coal mining methods – opencast and above-ground of underground coal mines – were studied in the arid desert region of northwest China. The mass concentrations of particulate matters, i.e., PM₁, PM₂.₅, PM₁₀ and TSP (total suspended particulate), were monitored by portable environmental PM meter during two windy seasons — spring and winter. The results show that the PM concentrations in both mining areas all exceeded a certain range of concentration limits. In the opencast mine, high concentrations of PM appeared in the mining area (MA), while it was concentrated in the coal yard (CY) in the above-ground of underground mine. The variations of pollution index (PI) showed similar patterns in both spring and winter at the opencast and above-ground of underground mine area respectively. In the opencast mine, the PM₁₀ and TSP concentrations varied more obviously from season to season and from area to area than the concentrations of PM₁ and PM₂.₅. Barometric pressure had the most significant influence on PM₁, PM₂.₅ and PM₁₀. Wind speed had the greatest influence on TSP. In the above-ground of underground mine, the variation patterns of the concentration of the four different-sized particulate matters were basically the same from area to area. The concentrations of PM₁ and PM₂.₅ had greater seasonal variation than PM₁₀ and TSP. The most important meteorological factors were temperature and barometric pressure for PM₁ and PM₂.₅, while air relative humidity had the greatest impact on PM₁₀ and TSP.