Air pollution and associated human mortality: The role of air pollutant emissions, climate change and methane concentration increases from the preindustrial period to present

EMIS, CLIM and TCH4 cause global population-weighted average PM2.5 (O₃) to change by +7.5 ± 0.19 μg m⁻³ (+25 ± 0.30 ppbv), +0.4 ± 0.17 μg m⁻³ (+0.5 ± 0.28 ppbv), and 0.04 ± 0.24 μg m⁻³ (+4.3 ± 0.33 ppbv), respectively. Total global changes in PM2.5 are associated with 1.5 (95% confidence interval, CI, 1.2-1.8) million cardiopulmonary mortalities and 95 (95% CI, 44-144) thousand lung cancer mortalities annually and changes in O₃ are associated with 375 (95% CI, 129-592) thousand respiratory mortalities annually.

Most air pollution mortality is driven by changes in emissions of short-lived air pollutants and their precursors (95% and 85% of mortalities from PM2.5 and O₃ respectively). However, changing climate and increasing CH₄ concentrations also contribute to premature mortality associated with air pollution globally (by up to 5% and 15%, respectively). In some regions, the contribution of climate change and increased CH₄ together are responsible for more than 20% of the respiratory mortality associated with O₃ exposure.

We find the interaction between climate change and atmospheric chemistry has influenced atmospheric composition and human mortality associated with industrial air pollution. Our study highlights the benefits to air quality and human health of CH₄ mitigation as a component of future air pollution control policy.