Association of short-term exposure to fine particulate air pollution and mortality: effect modification by oxidant gases.

ABSTRACT: Short term changes in exposure to outdoor fine particulate matter (PM_2.5) concentrations are associated with an increased risk of mortality. However, less is known about how oxidant gases may modify the acute health effects of PM_2.5. Our objective was to investigate whether associations between acute exposure to PM_2.5 and mortality were modified by the oxidant gases O₃ and NO₂ using their redox-weighted average (O_x). We conducted a multi-city case-crossover study in 24 cities across Canada between 1998-2011 including 1,179,491 nonaccidental mortality events. Interquartile increases in lag-0 and 3-day mean PM_2.5 and O_x concentrations were each associated with small increases in nonaccidental and cardiovascular mortality. In stratified analyses, associations between PM_2.5 and nonaccidental and cardiovascular mortality tended to be greatest in the highest tertile of O_x with a significant interaction observed between lag 0 PM_2.5 and 3-day mean O_x (interaction p-value?=?0.04). There was no evidence of effect modification by O_x in the relationship between PM_2.5 and respiratory mortality. Overall, the relationship between short-term changes in outdoor PM_2.5 and nonaccidental mortality may be greater when oxidant gas concentrations are also elevated. In some regions, reductions in oxidant gas concentrations may also reduce the acute health impacts of PM_2.5.

SUBMITTER: Lavigne E 

PROVIDER: S-EPMC6208424 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature