Mass Spectrometric Characteristics and Source Apportionment of PM2.5 in Winter in the Southern Suburbs of Xi' an.

To study the mass spectral characteristics and pollution sources of PM_2.5 in winter in the southern suburbs of Xi' an, this study used an online single-particle aerosol mass spectrometer to conduct online monitoring of fine particulate matter single particles in Xi' an from November 2020 to February 2021. The PM_2.5 obtained during the monitoring period was classified using an adaptive resonance neural network classification method, and the results showed that the percentages of elemental carbon, mixed carbon, organic carbon, K-rich, levoglucan, heavy metal, Na-rich, SiO₃, and other were 29.31%, 7.95%, 16.35%, 25.04%, 12.29%, 3.83%, 2.05%, 2.99% and 0.19%, respectively. Using the positive matrix factor decomposition model method, the seven sources were obtained including coal combustion source, industrial process source, motor vehicle exhaust source, construction dust source, biomass combustion source, wind and sand dust source and other sources, with the contribution rates of 32.4%, 25.9%, 19.4%, 7.4%, 6.6%, 2.7% and 5.6%, respectively, which showed that coal combustion source, industrial process source and motor vehicle exhaust source are the main sources of fine particulate matter in winter. The treatment of fine particulate matter pollution in winter in the southern suburbs of Xi' an should be based on the treatment of bulk coal combustion and industrial process emission reduction, while strengthening motor vehicle pollution control. [ABSTRACT FROM AUTHOR]