Modeling future asthma attributable to fine particulate matter (PM2.5) in a changing climate: a health impact assessment

Abstract

Exposure to fine particulate matter (PM_2.5) is associated with asthma development as well as asthma exacerbation in children. PM_2.5 can be directly emitted or can form in the atmosphere from pollutant precursors. PM_2.5 emitted and formed in the atmosphere is influenced by meteorology; future changes in climate may alter the concentration and distribution of PM_2.5. Our aim is to estimate the future burden of climate change and PM_2.5 on new and exacerbated cases of childhood asthma. Projected concentrations of PM_2.5 are based on the Geophysical Fluid Dynamics Laboratory Coupled Model version 3 climate model, the Representative Concentration Pathway 8.5 greenhouse gas scenario, and two air pollution emissions datasets: a 2011 emissions dataset and a 2040 emissions dataset that reflects substantial reductions in emissions of PM_2.5 as compared to the 2011 inventory. We estimate additional PM_2.5-attributable asthma as well as PM_2.5-attributable albuterol inhaler use for four future years (2030, 2050, 2075, and 2095) relative to the year 2000. Exacerbations, regardless of the trigger, are counted as attributable to PM_2.5 if the incident disease is attributable to PM_2.5. We project 38 thousand (95% CI 36, 39 thousand) additional PM_2.5-attributable incident childhood asthma cases and 29 million (95% CI 27, 31 million) additional PM_2.5-attributable albuterol inhaler uses per year in 2030, increasing to 200 thousand (95% CI 190, 210 thousand) additional incident cases and 160 million (95% CI 150, 160 million) inhaler uses per year by 2095 relative to 2000 under the 2011 emissions dataset. These additional PM_2.5-attributable incident asthma cases and albuterol inhaler use would cost billions of additional U.S. dollars per year by the late century. These outcomes could be mitigated by reducing air pollution emissions.

Keywords: Air pollution; Childhood asthma; Climate change; Fine particulate matter.

Fig. 1

Attributable risk model for incident asthma and exacerbated asthma with boxes A, B, C, D, E, F (Kunzli et al. 2008). PM_2.5, particulate matter with a mean aerodynamic diameter less than or equal to 2.5 micrometers

Fig. 2

Difference in rates of PM_2.5-attributable incident asthma per 100,000 population of children in 2095 compared to the baseline year 2000 on a state level under the CM3 climate model and the 2011 emissions scenario. PM_2.5, particulate matter with a mean aerodynamic diameter less than or equal to 2.5 micrometers; CM3, Coupled Model version 3; 100K, one hundred thousand

Fig. 3

Changes in PM_2.5-attributable incident asthma and exacerbated asthma in 2095 relative to 2000 with the CM3 climate model. Panels a and b Changes in PM_2.5-attributable incident asthma and exacerbation under the 2011 emissions inventory. Panel c and d Changes in PM_2.5-attributable incident asthma and exacerbation under the 2040 emissions inventory. Analogous results with the CESM climate model are given in Online Resource Fig S1. PM_2.5, particulate matter with a mean aerodynamic diameter less than or equal to 2.5 micrometers; CM3, Coupled Model version 3