Circulatory health risks from additive multi‑pollutant models: short‑term exposure to three common air pollutants in Canada
- DOI
- Language of the publication
- English
- Date
- 2022-09-29
- Type
- Article
- Author(s)
- Shin, Hwashin Hyun
- Owen, James
- Maquiling, Aubrey
- Parajuli, Rajendra Prasad
- Smith‑Doiron, Marc
- Publisher
- Springer Link
Abstract
Numerous studies have reported adverse health effects of ambient air pollution on circulatory health outcomes mainly based on single-pollutant models. However, limited studies have focused on adjusted effect of multi-pollutant exposures on public health. This study aimed to examine short-term effects of three common air pollutants—ground-level ozone (ozone), nitrogen dioxide (NO2), and fine particulate matter (PM2.5)—through multi-pollutant models for mixed effect of adjustment. Daily data (circulatory hospitalization and mortality) and hourly data (air pollutants and temperature) were collected for 24 Canadian cities for 2001–2012. We applied generalized additive over-dispersion Poisson regression models with 1, 2, or 3 pollutants for city-specific risks, and Bayesian hierarchical models for national risks. This study found little mixed effect of adjustment through multi-pollutant models (ozone and/or NO2 and/or PM2.5) for circulatory hospitalization or mortality in Canada for 2001–2012, indicating that the 1-pollutant model did not result in considerable under- or over-estimates. It seemed weak-to-moderate correlations among air pollutants did not change the significant effect of one air pollutant after accounting for others. Inconsistent findings between other previous studies and this study indicate the need of comparable study design for multi-pollutant effect analysis.
Plain language summary
Many scientific studies have investigated how air pollution relates to the incidence of heart- and brain blood vessel-related (circulatory) disease. Most such studies consider one pollutant at a time, but not the effect of mixtures of pollutants on public health. Whether or not simultaneous exposure to multiple air pollutants changes the effect on public health remains unclear, and is of interest as it is the most realistic exposure scenario. This study examined the short-term effects on circulatory disease of three common air pollutants: ground-level ozone (the harmful counterpart to beneficial atmospheric ozone), nitrogen dioxide, and fine particulate matter. Daily counts of hospitalization and mortality due to circulatory diseases were collected, along with hourly concentrations of the three air pollutants, for 24 cities across Canada from 2001-2012. We compared the risks of mortality and hospitalization associated with these pollutants, estimated by season (warm vs. cold) and time since exposure (up to six days), using 1- to 3-pollutant models to assess if considering mixtures produced different health risks. Overall, we found statistically insignificant differences in risk of circulatory health outcomes between single- and multi-pollutant models, indicating little additive effect from the three specified air pollutants. The study findings cannot be explained solely by correlations among the three specified air pollutants. Although further investigation is required, our study suggests little under- or over-estimates from 1-pollutant models, compared to 2- and 3-pollutant models in Canada.
Subject
- Health,
- Health and safety