Meteorological influences on the spatial and temporal variability of NO2 in Toronto and Hamilton |
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| Authors: | M. ALTAF ARAIN,ROSE BLAIR&dagger ,NORM FINKELSTEIN&Dagger ,JEFF BROOK§ ,MICHAEL JERRETT¶ |
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| Affiliation: | School of Geography and Earth Sciences, McMaster University, Hamilton, Ontario, Canada L8S 4K1 (e-mail: );
School of Geography and Earth Sciences, McMaster University, Hamilton, Ontario, Canada L8S 4K1 (e-mail: );
School of Geography and Earth Sciences, McMaster University, Hamilton, Ontario, Canada L8S 4K1 (e-mail:;);
Meteorological Service of Canada, Environment Canada, Toronto, Ontario, Canada M3H 5T4 (e-mail: );
Division of Environmental Health Sciences, School of Public Health, University of California-Berkeley, Berkeley, CA, USA 94720-7360 (e-mail: ) |
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| Abstract: | The spatial and temporal variability of nitrogen dioxide (NO2) concentrations and their relationships with meteorology was evaluated in the Toronto–Hamilton urban airshed. NO2 concentrations were highest in the early morning and late evening. Mean concentrations were highest in winter, although individual one-hour NO2 concentrations were found to be highest in summer. Wind direction was the strongest control on hourly NO2 concentration, and temperature and wind speed also had an effect. Our analysis of NO2 concentration variation by wind direction showed that areas downwind of major highways, urban centres and industry were exposed to higher pollutant concentrations. Seasonal patterns of NO2 concentration displayed significant spatial heterogeneity, in particular, in Toronto. Onshore winds sheltered coastal inhabitants from the full extent of NO2 exposure they would otherwise experience. Seasonal variations in meteorology and emissions mean that the degree of spatial variability in NO2 concentrations changes from season to season. This study will help to improve existing land-use regression-based NO2 prediction models by incorporating meteorological controls on NO2 distributions for health effect studies. |
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| Keywords: | nitrogen dioxide urban air quality air pollution health effects meteorology lake breeze |
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