Impacts Of Aerosol Radiation Effect On Surface Ozone During Heavy Haze Events

This study according to two heavy haze events analysis (Yangtze River delta in Dec, 2013 and Northeast China Region in Nov,2015), combined with the simulations of TUV (Troposphere Ultraviolet and Visible radiation) model, and NCAR MM model (Master Mechanism Box model, MM) to quantify the impact of aerosol radiation effect on surface ozone.The results indicate:1. When PM10 concentrations were less than 400 μg/m3, the aerosol radiation effect severely attenuated surface ozone concentration. This is due to the attenuation of surface-reaching ultraviolet radiations and weakened photochemical formation reactions for ozone. The main reason is that the radiation effect of aerosol is obviously weakened by the ultraviolet radiation.2. Based on different sites of China research results showed that 400 μg/m3 of PM10 concentration has a certain critical denotative meaning, more than 70% of the site supported the rule. The determination of the critical value is of great significance for quantitative study the effect of aerosol radiation effect of ground-level ozone concentration.3. In order to further explore the impacts of aerosols on surface ozone generating mechanism, the influences of aerosol and ozone precursor to ozone were simulated by using NCAR MM model through changing AOD and SSA. The results showed that ozone concentration increased with the decrease of AOD and the increase of SSA. With AOD increasing, the ozone concentration will continue decreasing and the change is less and less and finally tends to a constant value.4. The impact of AOD and SSA on ultraviolet radiation and key photochemical reactions were also evaluated by NCAR TUV radiation transfer model and the results indicated that the influence of aerosols to ozone mainly displayed both in the negative effect of AOD and the positive effect of SSA.