[How Does Climate Change Affect Air Quality in Taiwan?]

As global warming intensifies, Taiwan's air quality is significantly impacted, particularly in terms of fine particulate matter (PM_2.5) and ozone pollution. Air quality is influenced by multiple factors, from atmospheric conditions to various pollution sources, but it is challenging to clarify the contribution of each factor solely through observational data. Therefore, this study designed multiple numerical simulation experiments to delve into the effects of climate change on air quality, aiming to provide scientific insights for policymaking.

[ How Does Seasonal Pollution Change in Taiwan under Warming Scenarios? ]

Simulation results indicate that, in current climate conditions and future warming scenarios of 2°C and 4°C, Taiwan experiences generally higher PM_2.5 concentrations during winter. This is especially pronounced in the southern regions, where a prolonged period of high pollution continues until the spring of the following year. Geographically, the western regions of Taiwan show higher pollution concentrations than the east, with southern concentrations surpassing those in the north. Under the 4°C warming scenario, concentration changes are more intense compared to the 2°C scenario, though the overall trend remains similar, indicating that the extent of warming exacerbates pollution levels.

[ What Meteorological Factors Influence Seasonal Air Quality? ]

This study employs a fixed emissions inventory, with simulated PM_2.5 concentration changes primarily reflecting the impact of warming on meteorological conditions, including atmospheric stability, wind-terrain interactions, and precipitation. Under global warming scenarios, meteorological indices such as the Air Stagnation Index and Ventilation Index significantly influence air quality. The study finds that, in autumn, reduced low-level wind speeds are offset by increased rainfall, which helps improve air quality in southwestern Taiwan. In winter, however, enhanced northeastern monsoon days and increased wind speeds in northern Taiwan facilitate pollutant dispersion, slightly improving air quality in the north. These findings are essential for understanding the seasonal and regional variations in Taiwan’s air quality under climate change.