The coupling effects of sandstorm and dust from coal bases themselves can have a major impact on the atmospheric environment as well as on human health. The typical coal resource city of Wuhai in Inner Mongolia was selected in order to study these impacts during a severe sandstorm event in March 2021. Particulate matter (PM₁, PM_2.5 and PM₁₀) and total suspended particulate matter (TSP) samples were collected during the sandstorm event of 15–19 March 2021 and non-sandstorm weather (11–13 March 2021) and analyzed for their chemical composition. The concentrations of PM₁, PM_2.5, PM₁₀ and TSP in Wuhai city during the sandstorm were 2.2, 2.6, 4.8 and 6.0 times higher than during non-sandstorm days, respectively. Trace metals concentrations in particles of different sizes generally increased during the sandstorm, while water-soluble ions decreased. Positive matrix fraction (PMF) results showed that the main sources of particles during both sandstorm and non-sandstorm days were industrial emissions, traffic emissions, combustion sources and dust. The proportion of industrial emissions and combustion sources increased compared with non-sandstorm days, while traffic emissions and dust decreased. The backward trajectory analysis results showed that airflows were mainly transported over short distances during non-sandstorm days, and high concentration contribution source areas were from southern Ningxia, southeast Gansu and western Shaanxi. The airflow was mainly transported over long distances during the sandstorm event, and high concentration contribution source areas were from northwestern Inner Mongolia, southern Russia, northern and southwestern Mongolia, and northern Xinjiang. A health risk analysis showed that the risk to human health during sandstorm days related to the chemical composition of particles was generally 1.2–13.1 times higher than during non-sandstorm days. Children were more susceptible to health risks, about 2–6.3 times more vulnerable than adults to the risks from heavy metals in the particles under both weather conditions.

Identifying the coupling effect mechanisms of particulate matter (PM) in different functional areas on the atmospheric environment will help to carry out graded precision prevention and control measures against pollution within mining cities. This study monitored the pollution of three different functional areas in Wuhai, a typical mining city in Inner Mongolia. PM₁, PM_2.5, PM₁₀, and TSP were sampled and analyzed for chemical fractions both in the daytime and at night in spring, summer, autumn, and winter. The results showed that the average daily concentrations of PM were generally higher in the mining area than in the urban and sandy areas in different seasons. The results of the Kerriging analysis showed that the urban area was affected the most when specific ranges of high PM concentrations were detected in the mining area and specific ranges of low PM concentrations were detected in the sandy area. PMF results indicated that the source of pollutants in different functional areas and seasons were dust, industrial and traffic emissions, combustion, and sea salt. The contributions of dust in PM with different particle sizes in the mining and sandy areas were as high as 49–72%, while all the pollutant sources accounted for a large proportion of pollution in the urban area. In addition, dust was the largest source of pollution in summer and winter, and the contribution of combustion sources to pollution was higher in winter. Health risks associated with Cr were higher in the sandy area, and non-carcinogenic risks associated with Mn were higher in the mining area during spring and summer, while there was a greater impact on human health in the urban area during autumn and winter. The results of this study revealed the coupling effect mechanisms of different functional areas on the local atmospheric environment and contribute to the development of regional atmospheric defense and control policies.

 The particulate matter (PM) in coal mining can bring pollution to the surrounding environment and have 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 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 particulate matter meter during two windy seasons—spring and winter in a typical opencast coal mine and an underground coal mine. The results show that:(1) In the opencast mine, high concentrations of PM appeared in the mining area (MA) . Average PM10 and TSP concentration were 1950.18 μg·m-3 and 2393.56 μg·m-3 respectively in spring, while PM1 and PM2.5 concentration were 6.22 μg·m-3 and 42.58 μg·m-3 in winter. In the underground mine, it was concentrated in the coal yard (CY), average PM10 and TSP concentration were 920.95 μg·m-3 and 1225.89 μg·m-3 respectively in spring, while PM1 and PM2.5 concentration were 8.64 μg·m-3 and 35.93 μg·m-3  in winter.(2) The variations of pollution index (PI) showed similar patterns in both spring and winter— that is, high in the morning then achieved maximum value exceeded 10, and decreasing from noon at the opencast mine entrance (ME), the mining area (MA), road in the mine (RM), and the coal storage yard (CS). However, the PI rose in the evening in spring, but decreased in winter. In the CY of the underground mine, the PI was high during the day; whereas in the evening it decreased in spring and increased in winter.(3) 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 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 humidity had the greatest impact on PM10 and TSP.Considering the above results, it is recommended to control the daily occurrence and spread of particulate matter at 08:00 and 18:00 in the opencast mine, and from 08:00 to 16:00 in the underground mine. Primary attention should be given to the influence of wind speed and relative humidity changes on the diffusion of coarse particles(PM10 and TSP) in spring, while the influence of changes in barometric pressure on the diffusion of fine particles(PM1 and PM2.5) should be considered in the mining area in winter for both the two typical coal mining methods. The diffusion of coarse particulate matter in the opencast mine and of fine particulate matter in the underground mine are the main issues to be considered, while it is essential to prevent and control the spread of fine particles in the areas of roadways.