AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Source Contributions to Primary and Secondary Particulate Matter during a Severe PM2.5 Pollution Event in Xi’an, China
HONGLIANG ZHANG, Qi Ying, Dexiang Wang, Texas A&M University
Abstract Number: 110 Working Group: Source Apportionment
Abstract Airborne particulate matter with aerodynamic diameter of less than 2.5μm (PM2.5) reduces visibility and increases the incidence of respiratory diseases. While studies of PM2.5 have been conducted for years over East and South China, little was done for Central and Northwest China. In this study, the Community Multi-scale Air Quality (CMAQ) model is used to study a severe PM2.5 pollution event that affected many parts of China in January 2013. It is the first time such study is conducted over Northwest China.
Nested simulations of the Weather Research and Forecasting (WRF)/CMAQ modeling system was performed with a 12-km resolution inner domain centered on Xi’an, the capital of the northwest province of Shaanxi. Anthropogenic emissions were generated using the 0. 1x0.1 degree resolution EDGAR (Emission Database for Global Atmospheric Research) inventory while the biogenic emissions are generated using MEGAN (Model of Emissions of Gases and Aerosols from Nature) fused with updated vegetation cover data from local sources.
The model predictions of PM10 and PM2.5 are evaluated extensively with the recently-made-available public PM data, and show excellent agreement with with observations. Monthly averaged PM2.5 concentration in Xi’an exceeds 250 μg m-3. Both secondary inorganic matter (sulfate, nitrate and ammonium) and primary organic matter contribute to PM2.5. Windblown dust also contributes significantly to PM2.5 mass. Success of the WRF/CMAQ model in reproducing the observed high concentrations demonstrates the ability of state-of-art chemical transport model to act as a useful tool to investigate severe pollution events and provide crucial information needed to design control strategies. Source-oriented versions of the CMAQ model will be used to determine contributions to primary, secondary and overall PM2.5 from major emission sources, including residential heating, transportation, power generation, industry as well as windblown dust, to PM2.5 in the region.