1. Evaluation of emission inventory (EI) of air pollutants for Nanjing, China Y. ZHAO 1, L. Qiu 1, F. XIE 2, Q. ZHANG 3, Y. YU 4, C. NIELSEN 5, J. ZHANG 6 1. School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, China 2. Nanjing Academy of Environmental Protection Science, Nanjing, Jiangsu 210013, China 3. Center for Earth System Science, Tsinghua University, Beijing 100084, China 4. Nanjing Environmental Monitoring Central Station, Nanjing, Jiangsu 210013, China 5. School of Engineering and Applied Science, Harvard University, Cambridge, MA 02138 6. Jiangsu Provincial Academy of Environmental Science, Nanjing, Jiangsu 210036, China Top-Down Emissions Analyses, Oral Session 2

2. Background information of Nanjing Location: western Yangtze River Delta region in eastern China Intensive population and heavy industry (power, refinery, and steel) Large fossil fuel use (35 million metric tons coal in 2012) Serious air pollution (annual PM 10 in 2013 over 130 ug/m 3 ) Strong motivation to develop and improve city-scale EI

3. Development and evaluation of EI in Nanjing Lots of efforts. But do those efforts REALLY improve the quality of bottom-up city-scale EI ?

4. Emissions for typical sources/pollutants MEIC This work Power SO 2 Industrial PM 2.5

5. Spatial distribution of NO X emissions and NO 2 VCDs Agrees better with OMI observation compared to downscaled national EI Still missed source along the Yangtze River (ships and factories) Is the spatial distribution better captured ? Probably

6. Correlation between emissions and VCDs Particularly, emissions of medium/small sources are better detected.

7. Correlation between species: emissions vs observation BC/CO CO 2 /CO Top-down constraint: 0.0084 Bottom-up emissions: 0.0097 (this work)/0.0095 (MEIC) Top-down constraint: 86.9 Bottom-up emissions: 76.1 (this work)/52.8 (MEIC) Can the correlations be tested by observation? Probably

8. Main conclusions Contact: yuzhao@nju.edu.cn For More Information: Zhao et al., Atmos Chem Phys, 15, 12623-12644, 2015. Large point sources and super emitters play a key role on the level and spatial distribution of Nanjing emissions. The improved spatial distribution of NO X emissions at city level can be tested by satellite observation. Correlations between certain species in emissions can be tested through top-down constraints from ground observation.