Source attribution of PM2.5 pollution over North China using the adjoint method

2014 Fall Meeting Section: Atmospheric Sciences Session: Air Quality in Asia V Title: Source attribution of PM2.5 pollution over North China using the adjoint method Authors: Liu, L, Peking University, Beijing, China Zhang, L, Peking University, Beijing, China Gong, S, CAMS Chinese Academy of Meteorological Sciences, Beijing, China Zhao, Y, Peking University, Beijing, China Henze, D K, University of Colorado at Boulder, Boulder, CO, United States Abstract: Conventional methods for source attribution of air pollution are based on measurement statistics (such as Positive Matrix Factorization) or sensitivity simulations with a chemical transport model (CTM). These methods generally ignore the nonlinear chemistry associated with the pollution formation or require unaffordable computational time. Here we use the adjoint of GEOS-Chem CTM at 0.25x0.3125 degree resolution to examine the sources contributing to the PM2.5 pollution over North China in winter 2013. We improved the model sulfate simulation by implementing the aqueous-phase oxidation of S(IV) by nitrogen dioxide. The adjoint results provide detailed source information at the model underlying grid resolution including source types and sectors. We show that PM2.5 pollution over Beijing and Baoding (Hebei) in winter was largely contributed by the large-scale residential and industrial burnings, and ammonia (NH3) emissions from agriculture activities. Nearly half of pollution was transported from outside of the city domains, and accumulated over 2-3 days. We also show under the current emission conditions, the PM2.5 concentrations over North China are more sensitive to NH3 emissions than NOx and SO2 emissions. Cite as: Author(s) (2014), Title, Abstract A24A-04 presented at 2014 Fall Meeting, AGU, San Francisco, Calif., 15-19 Dec. Learn more here: http://abstractsearch.agu.org/meetings/2014/FM/A24A-04