Kim, D., Jeon, W., Bae, Y., Chang, D. Y., Jeong, S.*, Park, C.-R., Sou, H.-D., Park, J., Moon, J., Heo, M., Choe, H., Yang, C.-Y., & Kim, W. (2026). Regime-dependent air quality responses to biogenic emissions in complex mountainous terrain. Atmospheric Pollution Research, 17(7), 103042. https://doi.org/https://doi.org/10.1016/j.apr.2026.103042

Abstract:

Biogenic volatile organic compounds (BVOCs) are widely regarded as major precursors of ozone (O3) and fine particulate matter (PM2.5), yet conventional interpretations focus primarily on their role in worsening air quality. This perspective overlooks the potential for BVOCs to suppress secondary aerosol formation and fails to account for how net BVOC impacts vary with regional chemical regimes, limiting their utility for regional air quality assessment and management. In this study, we use the Model of Emissions of Gases and Aerosols from Nature (MEGAN) coupled with the Community Multiscale Air Quality (CMAQ) model to quantify BVOC contributions during June 2022 and assess their sensitivity to future climate warming. Domain-averaged results indicate that BVOCs account for 50.2 % of volatile organic compounds (VOCs), 4.7 % of O3, and 9.1 % of PM2.5. However, significant regional contrasts emerge: in NOx-saturated regions, BVOCs enhance O3 formation through interactions with anthropogenic emissions, while BVOCs oxidation depletes hydroxyl radicals (OH), suppressing sulfur and nitrogen oxidation and reducing sulfate, nitrate, and ammonium. We show that regional sulfur and nitrogen oxidation ratios (SOR and NOR) systematically govern the direction and magnitude of BVOC-induced PM2.5 changes, providing a diagnostic framework for interpreting spatially heterogeneous air quality responses. Under the SSP5-8.5 scenario, climate warming intensifies BVOC emissions and amplifies these divergent effects. Recognizing such regime-dependent BVOC impacts is critical for effective air quality management and climate adaptation strategies in complex terrain.