Environment Canada scientists completed a comprehensive air quality research study that increases our knowledge of the relationship between changes in both climate and emissions of pollutants, and the potential impacts of these changes on air quality, human health and ecosystems.

Air Quality Research Division and Climate Research Division scientists (J. Kelly, P.A. Makar and D.A. Plummer) used the Canadian General Circulation Model and the Canadian Regional Climate Model to create meteorological inputs for Environment Canada’s “A Unified Regional Air-quality Modelling System” (AURAMS), which is used to predict pollution concentrations for policy scenario simulations. The scientists carried out three simulations - one for present climate conditions, representative of the 2000s, and two with the same future climate conditions representative of the 2040s, but with different levels of smog precursor emissions. One objective was to assess air quality impacts of climate change alone, and then assess the impacts of changes in both climate and manmade emissions of pollutants such as nitrogen oxides, sulphur dioxide, ozone and fine particulate matter.

Results indicate that climate change will likely make air pollution and its effects worse over much of North America, compared to current conditions. The Air Quality Health Index values would increase, as would sulphur, nitrogen and ozone deposition to ecosystems. These effects may be counteracted through targeted pollutant emission reductions such as those implied by Representative Concentration Pathway 6.0 (RCP6), one of the scenarios used in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report.

The research results are published in the June 2012 issue of Atmospheric Chemistry and Physics, and appear in a column in the October 2012 issue of the preeminent scientific journal Nature Geoscience.

(a) is the Current Conditions 10 year average summer daily maximum 8 hour average O₃ in ppb, (b) shows the increase in O₃ relative to current conditions associated with climate change alone, (c) is the decrease in O₃ in the future climate when you have smog precursor emissions reductions, and (d) is the same field as (b), but plotted to the same colour scale as (c).  So (b) shows that O₃ increases with climate change, (c) shows that you can actually make O₃ much better in the future, despite climate change, if you reduce precursor emissions enough, and (d) shows that the increases in O₃ due to climate change are much smaller than the decreases you can get by reducing precursor emissions. | © Environment Canada

Contact: Dr. Paul Makar, Air Quality Research Division, 416-739-4692; and Dr. David Plummer, Climate Research Division, 514-282-6464 ext. 268