Investigation of the Spatio-Temporal Distribution and Seasonal Origin of Atmospheric PM_2.5 in Chenzhou City

Abstract

The objective of this study was to elucidate the transmission pathways and spatial distribution of potential source areas for PM2.5 pollution in Chenzhou City across diverse seasons in southern Hunan. Utilizing Sampling Kriging interpolation analysis, we modeled the temporal and spatial oscillations of PM2.5 concentrations in Chenzhou City, complemented by HYSPLIT air mass backward trajectories. Furthermore, the model conducted cluster analysis to identify discernible patterns. Our findings unveiled marked seasonal variations in PM2.5 concentrations within Chenzhou City. The pinnacle is discerned during winter (75.13 μg·m−3), whereas the nadir is pronounced in summer (27.64 μg·m−3). Notably, the PM2.5/PM10 ratio surpasses 0.55 during both autumn and winter. Spatially, Chenzhou exhibits an annual average distribution of PM2.5 pollution characterized by a gradient “from north to south in the western and central sectors, tapering towards the east”. Pollution source analysis suggests that PM2.5 pollution in Chenzhou City is predominantly ascribed to local emissions. Transmission pathway analysis reveals that the primary transmission corridors, spanning northwest Guangdong, southwestern Henan, Hubei, southern Anhui, and specific zones of southwestern Jiangxi, consistently align with external PM2.5 pollution sources affecting Chenzhou City throughout the year. Noteworthy seasonal disparities emerge in the spatial distribution and contribution of potential source regions. During spring, autumn, and winter, the predominant contributing regions are primarily located in adjacent provinces. In contrast, during summer, regions with relatively elevated values predominantly streak across the central and western sectors of Jiangxi and the southeastern Hunan region. A comprehensive examination of the seasonal distribution patterns, potential transmission routes, and likely contributing sources of PM2.5 in Chenzhou City can offer invaluable insights for regional atmospheric environmental governance. Furthermore, it underscores the paramount importance of collaborative regional strategies directed towards the prevention and control of PM2.5 pollution.

Keywords

• PM_2.5
• Kriging interpolation
• transmission path
• backward trajectory
• potential source area
• Chenzhou