Estimating emissions and concentrations of road dust aerosol over China using the GEOS-Chem model

Paved road dust is one of the most important aerosols in China. The authors estimated road dust emissions using an empirical model (AP-42 model) developed by the U.S. Environmental Protection Agency, and simulated road dust concentrations over China for the years 2006–2011 using the GEOS-Chem model. The annual road dust emissions amount averaged over 2006–2011 is estimated to be 2331.4 kt, with much higher emissions in eastern China than in western China. Because of heavy traffic and a dense road network, emissions are high over Beijing–Tianjin–Tanggu (BTT), Henan Province, and Shandong Province. Meanwhile, emissions are calculated to be 459.1, 112.0, and 102.7 kt, respectively, over BTT, the Pearl River Delta (PRD) region, and the Yangtze River Delta (YRD). Due to the monthly variation of precipitation, road dust emissions over China are simulated to be highest in December and lowest in June. The highest annual mean road dust concentration is simulated to be 14.5 μg m−3 in Beijing. Over 2006–2011, because of the increases in road length and number of vehicles, annual road dust emissions for China as a whole, BTT, the PRD, and the YRD, are simulated to increase by 260%, 239%, 266%, and 59%, respectively, leading to 233%, 243%, 273%, and 100% increases in road dust concentrations in these regions, respectively. Our results have important implications for air pollution control in China