Increases in surface ozone (O 3) and fine particu-late matter (≤ 2.5 µm aerodynamic diameter, PM 2.5) are as-sociated with excess premature human mortalities. We esti-mate changes in surface O 3 and PM 2.5 from pre-industrial (1860) to present (2000) and the global present-day (2000) premature human mortalities associated with these changes. We extend previous work to differentiate the contribution of changes in three factors: emissions of short-lived air pol-lutants, climate change, and increased methane (CH 4) con-centrations, to air pollution levels and associated prema-ture mortalities. We use a coupled chemistry-climate model in conjunction with global population distributions in 2000 to estimate exposure attributable to concentration changes since 1860 from each factor. Attributable mortalities are estimated using health impact functions of long-term rel-ative risk estimates for O 3 and PM 2.5 from the epidemi-ology literature. We find global mean surface PM 2.5 and health-relevant O 3 (defined as the maximum 6-month mean of 1-h daily maximum O 3 in a year) have increased by 8 ± 0.16 µg m −3 and 30 ± 0.16 ppbv (results reported as an-nual average ±standard deviation of 10-yr model simu-lations), respectively, over this industrial period as a re-sult of combined changes in emissions of air pollutants (EMIS), climate (CLIM) and CH 4 concentrations (TCH4). EMIS, CLIM and TCH 4 cause global population-weighted average PM 2.5 (O 3) 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 PM 2.5 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 O 3 are associated with 375 (95 % CI, 129–592) thousand respiratory mortalities an-nually. Most air pollution mortality is driven by changes in emissions of short-lived air pollutants and their precursors (95 % and 85 % of mortalities from PM 2.5 and O 3 respec-tively). However, changing climate and increasing CH 4 con-centrations also contribute to premature mortality associated with air pollution globally (by up to 5 % and 15 %, respec-tively). In some regions, the contribution of climate change and increased CH 4 together are responsible for more than 20 % of the respiratory mortality associated with O 3 expo-sure. We find the interaction between climate change and atmospheric chemistry has influenced atmospheric compo-sition and human mortality associated with industrial air pol-lution. Our study highlights the benefits to air quality and human health of CH 4 mitigation as a component of future air pollution control policy.