Temperature Regulates BVOCs-Induced O3 Formation Potential Across Various Vegetation Types in the Sichuan Basin, China

Ground-level ozone (O3) pollution is a problem when managing air quality in China, and biogenic volatile organic compounds (BVOCs) are key precursors of O3 formation. Vegetation type and temperature influence BVOC emissions, yet the differences in emissions across vegetation types and their temperature responses still exhibit significant uncertainties. This study was focused on the Sichuan Basin in China. It used the G95 model to develop a high-resolution BVOC emission inventory, allowing the analysis of emission characteristics for different vegetation types. The study also used a temperature sensitivity algorithm to assess how temperature changes affect BVOC emissions. The impact of these emissions on regional O3 formation potential (OFP) was then quantified using the OFP method. The results show significant differences in BVOC emissions across vegetation types. Forests at the basin edges (mixed, broad-leaved, and coniferous) have much higher emission intensity (10.5 t/km2) than agricultural areas in the center of the basin (0.15 t/km2). In terms of composition, monoterpenes (MON) mainly dominate mixed and coniferous forests (42.28% and 58.37%, respectively), while isoprene (ISOP) dominates broad-leaved forests (64.02%). The study found that temperature generally increases BVOC emissions, which vary by vegetation type. Broad-leaved forests have the highest temperature sensitivity (3.94%), much higher than agricultural vegetation (0.03%). BVOC emissions exhibit a seasonal pattern of “high in summer, low in winter” and a spatial pattern of “high at the edges, low at the center”. Temperature also influences emission intensity and composition, thus driving variations in the potential for O3 formation. Seasonally, different vegetation types show structural changes in OFP contribution. Broad-leaved forests, dominated by ISOP, show a significant increase in summer contribution (+8.0%), becoming the main source of O3 precursors. In contrast, mixed forests, dominated by MON, show a clear decrease in summer contribution (−6.3%).