The mortality burden attributable to PM_2.5 and NO₂ from all sources and traffic-related air pollution in Australia

Fine particulate matter (PM_2.5) and nitrogen dioxide (NO₂) are associated with multiple health risks, including death. In Australia, the mortality burden attributable to PM_2.5 has been estimated, but there are no published estimates for NO₂ or the combined impacts of both pollutants.

To estimate the mortality burden attributable to PM_2.5 and NO₂ from all anthropogenic sources and traffic-related air pollution (TRAP) in Australia.

We used previously published predictions for all source PM_2.5 and NO₂ and chemical transport model outputs to estimate TRAP-related concentrations. We estimated the attributable number of deaths by applying a life tables approach. We used publicly available population and mortality data together with effect estimates obtained from global meta-analyses, and incorporated recent recommendations for including single- and two-pollutant effect estimates into health impact assessment methods for air pollution. We did a series of sensitivity analyses to assess the influence of different modelling approaches and choices on our results.

In 2015, an estimated 3684 (95 % CI, 3051-4350) premature deaths were attributable to air pollution from all sources, with 51 % (95 % CI, 19 %-86 %) linked to TRAP. Using mutually adjusted coefficients from two pollutant models and summing results did not appreciably change estimates derived from a single pollutant marker. Our results support PM_2.5 as a reliable marker for mortality impacts from diverse emission sources, and NO₂ as a robust marker for TRAP-related mortality in Australia. Sensitivity analyses including exposures below low-threshold cutoffs, using estimates for low pollution settings, and using location-specific threshold cutoffs for NO₂, yielded higher mortality estimates. This suggests our results may be conservative.

Air pollution remains a significant contributor to mortality in Australia. Reducing exposure, particularly from TRAP, could yield substantial public health benefits. Policies promoting cleaner transport modes offer a promising avenue for rapid improvement.