Dan L Crouse1, Anders C Erickson2, Tanya Christidis3, Lauren Pinault3, Aaron van Donkelaar4, Chi Li4, Jun Meng4, Randall V Martin4, Michael Tjepkema3, Perry Hystad5, Rick Burnett6, Amanda Pappin3, Michael Brauer2, Scott Weichenthal7,8. 1. From the University of New Brunswick, Fredericton, NB, Canada. 2. University of British Columbia, Vancouver, BC, Canada. 3. Statistics Canada, Ottawa, ON, Canada. 4. Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada. 5. Oregon State University, Corvallis, OR. 6. Population Studies Division, Health Canada, Ottawa, ON, Canada. 7. Air Health Science Division, Health Canada, Ottawa ON, Canada. 8. Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, QC.
Abstract
BACKGROUND: The temporal and spatial scales of exposure assessment may influence observed associations between fine particulate air pollution (PM2.5) and mortality, but few studies have systematically examined this question. METHODS: We followed 2.4 million adults in the 2001 Canadian Census Health and Environment Cohort for nonaccidental and cause-specific mortality between 2001 and 2011. We assigned PM2.5 exposures to residential locations using satellite-based estimates and compared three different temporal moving averages (1, 3, and 8 years) and three spatial scales (1, 5, and 10 km) of exposure assignment. In addition, we examined different spatial scales based on age, employment status, and urban/rural location, and adjustment for O3, NO2, or their combined oxidant capacity (Ox). RESULTS: In general, longer moving averages resulted in stronger associations between PM2.5 and mortality. For nonaccidental mortality, we observed a hazard ratio of 1.11 (95% CI = 1.08, 1.13) for the 1-year moving average compared with 1.23 (95% CI = 1.20, 1.27) for the 8-year moving average. Respiratory and lung cancer mortality were most sensitive to the spatial scale of exposure assessment with stronger associations observed at smaller spatial scales. Adjustment for oxidant gases attenuated associations between PM2.5 and cardiovascular mortality and strengthened associations with lung cancer. Despite these variations, PM2.5 was associated with increased mortality in nearly all of the models examined. CONCLUSIONS: These findings support a relationship between outdoor PM2.5 and mortality at low concentrations and highlight the importance of longer-exposure windows, more spatially resolved exposure metrics, and adjustment for oxidant gases in characterizing this relationship.
BACKGROUND: The temporal and spatial scales of exposure assessment may influence observed associations between fine particulate air pollution (PM2.5) and mortality, but few studies have systematically examined this question. METHODS: We followed 2.4 million adults in the 2001 Canadian Census Health and Environment Cohort for nonaccidental and cause-specific mortality between 2001 and 2011. We assigned PM2.5 exposures to residential locations using satellite-based estimates and compared three different temporal moving averages (1, 3, and 8 years) and three spatial scales (1, 5, and 10 km) of exposure assignment. In addition, we examined different spatial scales based on age, employment status, and urban/rural location, and adjustment for O3, NO2, or their combined oxidant capacity (Ox). RESULTS: In general, longer moving averages resulted in stronger associations between PM2.5 and mortality. For nonaccidental mortality, we observed a hazard ratio of 1.11 (95% CI = 1.08, 1.13) for the 1-year moving average compared with 1.23 (95% CI = 1.20, 1.27) for the 8-year moving average. Respiratory and lung cancer mortality were most sensitive to the spatial scale of exposure assessment with stronger associations observed at smaller spatial scales. Adjustment for oxidant gases attenuated associations between PM2.5 and cardiovascular mortality and strengthened associations with lung cancer. Despite these variations, PM2.5 was associated with increased mortality in nearly all of the models examined. CONCLUSIONS: These findings support a relationship between outdoor PM2.5 and mortality at low concentrations and highlight the importance of longer-exposure windows, more spatially resolved exposure metrics, and adjustment for oxidant gases in characterizing this relationship.
Authors: Rajan K Chakrabarty; Payton Beeler; Pai Liu; Spondita Goswami; Richard D Harvey; Shamsh Pervez; Aaron van Donkelaar; Randall V Martin Journal: Sci Total Environ Date: 2020-11-09 Impact factor: 7.963
Authors: Scott Weichenthal; Lauren Pinault; Tanya Christidis; Richard T Burnett; Jeffrey R Brook; Yen Chu; Dan L Crouse; Anders C Erickson; Perry Hystad; Chi Li; Randall V Martin; Jun Meng; Amanda J Pappin; Michael Tjepkema; Aaron van Donkelaar; Crystal L Weagle; Michael Brauer Journal: Sci Adv Date: 2022-09-28 Impact factor: 14.957