1. Analysis of PM10 Readings in Beijing, July, 2008 Data from BBC Analysis by Thomas A. Cahill, Professor of Physics and Atmospheric Sciences and Head, DELTA Group, University of California, Davis 95616 http://delta.ucdavis.edu tacahill@ucdavis.edu

2. Publications using HYSPLIT results, maps or other READY products provided by NOAA ARL are requested to include an acknowledgement of, and citation to, the NOAA Air Resources Laboratory. Appropriate versions of the following are recommended: Citation Draxler, R.R. and Rolph, G.D., 2003. HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) Model access via NOAA ARL READY Website (http://www.arl.noaa.gov/ready/hysplit4.html). NOAA Air Resources Laboratory, Silver Spring, MD. Rolph, G.D., 2003. Real-time Environmental Applications and Display sYstem (READY) Website (http://www.arl.noaa.gov/ready/hysplit4.html). NOAA Air Resources Laboratory, Silver Spring, MD. Acknowledgment The authors gratefully acknowledge the NOAA Air Resources Laboratory (ARL) for the provision of the HYSPLIT transport and dispersion model and/or READY website (http://www.arl.noaa.gov/ready.html) used in this publication HYSPLIT Analyst: Thomas A. Cahill

4. PM10 in Beijing by BBC

5. 1121China S of Beijing 2172China S of Beijing 3122China S of Beijing 4351China S of Beijing 5112China S of Beijing 627Mongolia 7242China S of Beijing 8248China S of Beijing 982China SE of Beijing 10145China S of Beijing 11172China SE of Beijing 128Mongolia 1369Mongolia plus slow SW loop 14225China S of Beijing 1525China SE of Beijing 1644Mongolia 1712Mongolia 18105China SW of Beijing 1947China fast NE of Beijing 2032China S of Beijing 2168China very slow E of Beijing 22107China S and E of Beijing 23143China S of Beijing 24254China S of Beijing 25261China S of Beijing

6. Summary: about ½ of all days in July, 2008, winds were from south of Beijing with the highest pollution level; average = 202.2  g/m 3 (max = 351  g/m 3 ) Trajectories from Mongolia, relatively high wind velocities – avg 23  g/m 3 4 days Mongolia plus slow SW loop – 69.0  g/m 3 1 day Trajectories south of Beijing, relatively low wind velocities – avg 202.2  g/m 3 12 days Trajectories south and east of Beijing, relatively low wind velocities – avg 96.7  g/m 3 4 days Trajectory SW of Beijing – 105  g/m 3 1 day Trajectory NE of Beijing – fast wind velocities – avg 32.0  g/m 3 1 day