Air pollution and associated human mortality: the role of air pollutant emissions, climate change and methane concentration increases from the preindustrial period to present
- ISSN: 1680-7324
- DOI: 10.5194/acp-13-1377-2013
Increases in surface ozone (O3) and fine particu- late matter (≤2.5µm aerodynamic diameter, PM2.5) are as- sociated with excess premature human mortalities. We esti- mate changes in surface O3 and PM2.5 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 (CH4) 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 O3 and PM2.5 from the epidemi- ology literature. We find global mean surface PM2.5 and health-relevant O3 (defined as the maximum 6-month mean of 1-h daily maximum O3 in a year) have increased by 8±0.16 µgm−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 CH4 concentrations (TCH4). EMIS, CLIM and TCH4 cause global population-weighted average PM2.5 (O3) to change by +7.5±0.19 µgm−3 Geoscientific (+25±0.30 ppbv), +0.4±0.17 µgm−3 (+0.5±0.28 ppbv), Instrumentation and 0.04±0.24 µgm−3 (+4.3±0.33 ppbv), respectively. Methods and Total global changes in PM2.5 are associated with 1.5 (95% Open Access confidence interval, CI, 1.2–1.8) million cardiopulmonary Data Systems 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 an- Geoscientific nually. Most air pollution mortality is driven by changes in emissions of short-lived air pollutants and their precursors Model Development Open Access (95% and 85% of mortalities from PM2.5 and O3 respec- tively). However, changing climate and increasing CH4 con- centrations also contribute to premature mortality associated Hydrology and with air pollution globally (by up to 5% and 15 %, respec- tively). In some regions, the contribution of climate change Earth System and increased CH4 together are responsible for more than Sciences Open Access 20% of the respiratory mortality associated with O3 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- Ocean Science lution. Our study highlights the benefits to air quality and human health of CH4 mitigation as a component of future air Open Access pollution control policy.