Summertime Biogenic Volatile Organic Compounds in China: Emissions and Their Modulation on O3 and PM2.5 Pollution

Coordinated control of fine particulate matter (PM2.5) and ozone (O3) is an urgent national strategic priority for China’s air pollution governance. Biogenic volatile organic compounds (BVOCs) are important precursors of O3 and secondary organic aerosol (SOA). To quantify the species-specific impacts of BVOCs, we used the Model of Emissions of Gases and Aerosols from Nature (MEGAN, v3.2) and the Community Multiscale Air Quality (CMAQ, v5.3.2) model to investigate BVOC emission characteristics and their modulating effects on summertime O3 and PM2.5 across China. In July 2020, total BVOC emissions were 6.50 × 106 tons, showing a spatial pattern that decreased from southeast to northwest and a unimodal diurnal variation that peaked at 13:00–14:00. BVOC emissions significantly promoted O3 formation, with a maximum concentration increment of 47.36 μg m−3 in VOC-limited regions such as the Sichuan Basin (SCB) and Yangtze River Delta (YRD). Their impact on PM2.5 was limited, with most regional increments below 3 μg m−3. Isoprene dominated O3 enhancement, while monoterpenes acted as the key BVOC for PM2.5 via SOA formation. Anthropogenic emission reductions elevated the relative contribution of BVOC emissions to air pollution in most regions. These findings highlighted the importance of considering BVOC emissions and their species-specific effects in China’s coordinated PM2.5-O3 control strategies for more precise air quality management.