1. Air Quality Research Branch; Meteorological Service of Canada; Toronto, Ontario Canada
2. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment; Chinese Academy of Sciences; Xian China
3. Department of Chemical Engineering and Applied Chemistry; University of Toronto; Toronto, Ontario Canada
4. Atmospheric Science Programme/Geography; University of British Columbia; Vancouver, British Columbia Canada
5. University of Washington-Bothell; Bothell Washington USA
6. National Satellite and Meteorological Center; Chinese Meteorological Administration; Beijing China