The assessment of emission-source contributions to air quality by using a coupled MM5-ARPS-CMAQ modeling system: A case study in the Beijing metropolitan region, China

A coupled MM5-ARPS-CMAQ air quality modeling system was applied for investigating the contributions of various emission sources to the ambient concentrations of PM10 in the Beijing metropolitan region of China. A three-level nested simulation domain was established for facilitating the modeling study, and a GIS-based atmospheric pollutant emission database was constructed to provide important emission information for the Models-3/CMAQ model. After verification, the coupled modeling system was implemented to predict the hourly contribution ratios of various PM10 emission sources to Beijing’s air quality during four representative months of January, April, August and October in the base year of 2002. It was found from the modeling results that three major sources (including fugitive industrial emissions, construction sites, and road dusts) presented a relatively high contribution to the PM10 pollution in Beijing, with the contribution ratios of 28.67%, 42.88%, 42.46% and 35.67% for spring, summer, autumn and winter, respectively. In addition, the impacts of emissions from two major industrial zones within Beijing on its air quality were quantified. Moreover, the coupled modeling system was applied to explore possible future PM10 concentration distributions in 2008 through two proposed emission sources reduction strategies. It was found that Beijing needs to take continual emission control efforts to comprehensively improve its air quality to the Class II level by 2008. The modeling results could provide sound decision making basis for developing effective air quality management strategies in the planning region.