The Modulation of Climate and Biogenic Emissions on the Ozone Pollution in Pearl River Delta Region

The observational data from 2015-2019 shows that there is substantial increasing trend of ozone concentration in majority regions of China in summer and fall. To investigate the modulation of meteorology on ozone variations over the Pearl River Delta (PRD) region, the numerical experiments with three dimensional model Weather Research and Forecasting-Community Multiscale Air Quality are conducted. While the model in general well reproduce the observed trend in ozone concentration, the sensitivity reveals that the interannual variability of meteorology substantially governs the trends in ozone variations. The modulation takes effect from twofold. On the one hand, the enhanced photochemical reactions trigger faster ozone formation and accumulations. On the other hand, the increase in biogenic emissions play a pivotal role in the ozone increase. Because of the effects of biogenic emissions, ozone increased 10.7%. It implies that under an emission decrease in future, the consideration of meteorology in particular of extreme weather events may be crucial in ozone attainment.