Simulations And Development Of CMAQ Model For Atmospheric Transport And Deposition Of Benzo(a)Pyrene

Benzo[a]pyrene (BaP) is one of the most dangerous polycyclic aromatic hydrocarbons (PAHs) with strong carcinogenicity and mutagenicity. The spatial distributions and seasonal variations of BaP concentrations as well as dry and wet deposition are simulated for the entire year of 2014 in China. Simulation results of this study are as follows:1. The modules for simulating transport, transformation and deposition processes, as well as gas/particle partitioning (KOA absorption mechanism) processes of atmospheric BaP were added into the CMAQ, a regional air quality model developed by U.S. E.P.A. in this study.2. The comparison between modeled and observed BaP concentrations and BaP deposition fluxes showed the predicted values were in an acceptable range.3. The distribution of BaP concentration was the same as the BaP emissions. High emissions were the main reason for the centralized distribution of BaP concentration. The seasonal variation of BaP concentration depended not only on the spatial distribution of emissions, but also on the weather conditions. The BaP concentration had a reverse relationship with temperature and boundary layer height.4. The concentration of particle-phase BaP was positively correlated with the daily variation of PM2.5, CO, NO2, SO2 concentration and inversely related to O3 concentration.5. The predicted deposition results also showed that the wet deposition is the dominant deposition pathway. The spatial distributions of the BaP depositions were closely related to that of the anthropogenic emissions and presented obvious long-distance transportation characteristics. The author also assessed the impact of weather conditions on the BaP deposition. The results showed that the BaP deposition had a positive correlation with precipitation. The dry and wet deposition processes of gas-phase BaP in this work was ignored.