## 5 Conclusions  
(1) From March 2022 to March 2023, Chenzhou City exhibits discernible seasonal variations in the average concentrations of PM\({}_{2.5}\) and PM\({}_{10}\). The zenith of these concentrations is observed during winter, registering at 75.13 \(\upmu\)g\(\cdot\)m\({}^{-3}\) for PM\({}_{10}\). Autumn follows with a moderate average, while summer records the nadir. The seasonal average ratio of PM\({}_{2.5}\) to PM\({}_{10}\) unfolds as follows: winter (0.61) > autumn (0.58) > spring (0.54) > summer (0.48), underscoring that the city grapples with its most concentrated pollution levels during autumn and winter. While PM\({}_{2.5}\) pollution predominates year-round, PM\({}_{10}\) pollution manifests more acutely during spring and summer. (2) In Chenzhou City, PM\({}_{2.5}\) exhibits a positive correlation with PM\({}_{10}\), CO, NO\({}_{2}\), and SO\({}_{2}\), while manifesting a negative association with O\({}_{3}\). Spatially, the annual average distribution of PM\({}_{2.5}\) in Chenzhou City reveals a pollution gradient: concentrations peak from north to south in the eastern and central regions, tapering to lower levels in the west. Notably, the Beihu District, Suxian District, the southeastern sector of Yongxing County, the southwestern sector of Zixing County, and the northwestern area of Rucheng County bear the brunt of severe pollution. Conversely, Guidong County and the southeastern portion of Yizhang County present the least pollution, with localized emissions being a contributing factor to these high-pollution zones. Seasonally, PM\({}_{2.5}\) distribution exhibits nuanced variations. Pollution concentrations in the southern and western regions witness a marked decline in spring, with summer recording the least average PM\({}_{2.5}\) concentration. However, pollution intensifies notably in autumn, transitioning low-concentration areas in the south and west into high-pollution zones. Winter's spatial distribution of PM\({}_{2.5}\) largely mirrors the annual average pattern. (3) The trajectory analysis reveals that Chenzhou City predominantly experiences short-range air pollution transmissions across all four seasons. During summer, the air masses reaching Chenzhou carry diminished PM\({}_{2.5}\) concentrations, predominantly comprising pristine air masses. In contrast, autumn and winter emerge as the principal seasons of pollution, with contaminant-laden air masses predominantly originating from northeastern Hunan and southeastern Jiangxi. A comprehensive examination indicates that Chenzhou City's air quality is substantially influenced by southern Jiangxi, central and northern Guangdong, and the local environs of central and northern Hunan, which are the primary contributors to the city's pollution throughout the year. (4) The analysis of WPSCF (Weighted Potential Source Contribution Function) and WCWT (Concentration-Weighted Trajectory) in Chenzhou City reveals pronounced seasonal variations in the potential source areas of PM\({}_{2.5}\). Predominantly, the principal source areas are concentrated during autumn and winter. However, the spatial distribution of these main contributing zones undergoes alterations in winter, with pollutant concentrations marginally lower than those observed in autumn. In contrast, the contribution from these areas diminishes substantially during spring and summer. Specifically, during spring, autumn, and winter, these primary source areas are situated in southwestern Jiangxi, northwestern Guangxi, and southeastern Hunan. In the summer, the elevated concentration zones form elongated belts spanning the central and western regions of Jiangxi and southwestern Hunan. (5) Chenzhou City remains predominantly influenced by industrial emissions, combustion processes, and vehicular exhaust. Based on the findings of this study, future endeavors in pollution prevention and control might strategically pivot towards restructuring the industrial energy landscape.