# VDMS: An Improved Vision Transformer-Based Model for PM\({}_{2.5}\) Concentration Prediction
## 5 Discussion
### Analysis in Time and Space  
According to the statistical analysis of seasonal PM\({}_{2.5}\) concentrations in Beijing, notable seasonal variations are apparent, attributable to multiple factors. Winter serves as the heating season in Beijing, during which the demand for heating significantly increases, resulting in heightened energy consumption and pollutant emissions [45]. Specifically,the reliance on coal and heating equipment contributes to a substantial accumulation of pollutants, including PM\({}_{2.5}\), during this season. Moreover, the lower temperatures, reduced air circulation, and frequent occurrences of temperature inversions in winter facilitate the retention of pollutants near the ground, thereby exacerbating air pollution [46]. Conversely, summer displays the lowest PM\({}_{2.5}\) concentrations, marked by pronounced seasonal fluctuations. This is primarily due to elevated temperatures and improved air circulation during the summer months, which promote the dispersion and dilution of pollutants, thereby reducing PM\({}_{2.5}\) accumulation. Moreover, increased precipitation during summer aids in the removal of suspended particulate matter from the atmosphere, further lowering PM\({}_{2.5}\) levels. Despite the significant seasonal variations, the data reveal a gradual decline in PM\({}_{2.5}\) concentrations over the three-year period, indicating substantial progress in Beijing's ongoing efforts to enhance air quality [47]. In recent years, the government has implemented a series of stringent regulatory measures targeting industrial emissions, traffic-related pollution, and energy consumption, including the promotion of clean energy, improved traffic management, and the enforcement of stricter emission standards. These measures have effectively reduced pollutant emissions and contributed to improve air quality to some extent [48]. Furthermore, recent enhancements in Beijing's air quality can also be partially attributed to climatic influences, such as stronger winds, increased precipitation during summer, and a decrease in extreme pollution events during winter.  
From a spatial perspective, Western China--particularly regions near Xinjiang--exhibits higher PM\({}_{2.5}\) concentrations, primarily due to the combined effects of dust storms and industrial emissions. Frequent dust storms in the western region elevate the amount of particulate matter in the atmosphere, while ongoing industrialization in specific areas further aggravates pollution. In contrast, the eastern and southern regions of China show lower PM\({}_{2.5}\) concentrations, largely due to the improved air circulation, increased precipitation, and stringent pollution control measures that help mitigate pollutant accumulation [49]. Moreover, the eastern region relies more heavily on clean energy and utilizes less coal, thereby reducing pollutant emissions. Despite these regional disparities, overall PM\({}_{2.5}\) concentrations in China have demonstrated a gradual year-on-year decline from 2020 to 2022 [50]. This trend highlights the significant achievements in national pollution control efforts, particularly through the implementation of strict environmental policies and measures, such as promoting clean energy, reducing coal dependency and strengthening industrial emission regulations, which have consistently improved the air quality. The effects of these policies are especially pronounced in the eastern and southern regions, while the reduction in PM\({}_{2.5}\) concentrations in the western region is more contingent upon a decrease in the frequency of dust storms and improved local governance. As national pollution control policies continue to be enforced, PM\({}_{2.5}\) concentrations across various regions in China are expected to further improve in the coming years [50].