1. Department of Earth Sciences, University of Toronto, 22 Ursula Franklin Street, Toronto, Ontario M5S 3B1, Canada
2. Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Avenue, Toronto, Ontario M5S 3B2, Canada
3. Air Quality Processes Research Section, Environment and Climate Change Canada, Egbert, Ontario L0L 1N0, Canada
4. Ministry of the Environment, Conservation and Parks, Toronto, Ontario M9P 3V6, Canada
5. School of the Environment, University of Toronto, Toronto, Ontario M5S 3E8, Canada