Objective To investigate the concentration distribution characteristics of metals and metalloids (the following were all referred to as metals) in atmospheric fine particulate matter (PM2.5) in typical areas of Inner Mongolia, China, in 2024, to analyze their pollution sources.
Methods PM2.5 concentrations and their associated metal and metalloid concentrations were collected from the typical areas of Inner Mongolia—Hohhot, Baotou, and Ordos—in 2024. The positive matrix factorization method was employed to analyze pollution sources.
Results The 24-hour average PM2.5 concentrations in Hohhot(34.3 μg/m3), Baotou(43.0 μg/m3) and Ordos(72.3 μg/m3) areas didn't exceeded the Grade Ⅱ standard limit of the Ambient air quality standards(GB 3095-2012) in 2024. The most abundant PM2.5-bound metal and metalloid elements in all three typical areas were Al and Mn. Source apportionment results showed that the main pollution sources in Hohhot were traffic/industrial mixed sources and industrial sources, with relatively large contributions from Cr, Pb, and Ni with contribution rates of 95.93%, 71.23%, and 68.18%, respectively. In Baotou, the main pollution sources were dust/industrial mixed sources and coal combustion/vehicle mixed sources, with relatively large contributions from Ni, Se, and Tl with contribution rates of 87.57%, 85.61%, and 78.58%, respectively. In Ordos, the main pollution sources were dust/industrial mixed sources and industrial sources, with relatively large contributions from Al, Mn, and Ni with contribution rates of 87.17%, 85.98%, and 81.20%, respectively.
Conclusion This study indicates that certain atmospheric PM2.5 pollution problems exist in Hohhot, Baotou, and Ordos in Inner Mongolia, with distinct core pollution sources in each city. The findings of this study can serve as a scientific reference for differentiated and targeted air pollution source control efforts in typical areas of Inner Mongolia, providing strong support for precise regional air pollution control.
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