1. Department of Chemistry; University of Toronto; Toronto Ontario Canada
2. Department of Atmospheric Science; Colorado State University; Fort Collins CO USA
3. Centro de Ciencias de la Atmósfera; Universidad Nacional Autonoma de Mexico; Mexico City Mexico
4. Department of Civil and Environmental Engineering; National University of Singapore; Singapore
5. Department of Chemistry, Faculty of Science; University of British Columbia; Vancouver British Columbia Canada
6. Environment and Climate Change Canada; Toronto Ontario Canada
7. Department of Environment and Geography; University of Manitoba; Winnipeg Manitoba Canada