Component Characteristics and Source Apportionment of Fine Particulate Matter (PM2.5) in WJQ City during Autumn and Winter

This study investigates the status of fine particulate matter (PM2.5) pollution during the autumn and winter seasons of 2022-2023. Utilizing thorough data analysis alongside scientific research techniques, it uncovers the characteristics and sources of PM2.5 components with the goal of offering scientific guidance for pollution management in WJQ City. The findings demonstrate that the primary components of ambient PM2.5 in WJQ during this time frame are sulfate (SO42-) and nitrate (NO3-), with concentrations of 33.90 μg/m3 and 28.88 μg/m3, respectively, making up 25% and 22% of the total. Ammonium (NH4+) concentrations are recorded at 19.43 μg/m3, representing 15.27%, which is slightly lower than those of SO42- and NO3-. In total, SO42-, NO3-, and NH4+ concentrations reach 82.22 μg/m3, accounting for 61.54% of the overall particulate matter, thereby highlighting the substantial impact of secondary sources during the autumn and winter months. The primary source of SO42- can be attributed to the secondary conversion of sulfur dioxide (SO2) from coal combustion, as well as from primary emissions occurring during the wet desulfurization of coal-fired boilers. The increased levels of SO42- indicate a significant influence of coal-burning activities on WJQ's air quality during these seasons. Chloride (Cl-) and sodium (Na) are also present at concentrations of 3.33 μg/m3 (2.76%) and 1.23 μg/m3 (1.41%), respectively. The ambient concentration of NO3- primarily arises from the secondary conversion of nitrogen oxides (NOX) produced by industrial operations, coal burning, and vehicle emissions. The notably elevated NO3- levels in autumn and winter further emphasize the significant impact of both coal-burning and industrial activities in WJQ. Additionally, the concentrations of heavy metals such as iron (Fe), aluminum (Al), and zinc (Zn) are considerably higher compared to other heavy metal elements, while arsenic (As), chromium (Cr), and cadmium (Cd) levels remain relatively low.