Climate Change, Tropospheric Ozone and Particulate Matter, and Health Impacts
Ebi, Kristie L., McGregor, Glenn, Environmental Health Perspectives
OBJECTIVE: Because the state of the atmosphere determines the development, transport, dispersion, and deposition of air pollutants, there is concern that climate change could affect morbidity and mortality associated with elevated concentrations of these gases and fine particles. We review how climate change could affect future concentrations of tropospheric ozone and particulate matter (PM), and what changing concentrations could mean for population health.
DATA SOURCES: We review studies projecting the impacts of climate change on air quality and studies projecting the impacts of these changes on morbidity and mortality.
DATA SYNTHESIS: Climate change could affect local to regional air quality through changes in chemical reaction rates, boundary layer heights that affect vertical mixing of pollutants, and changes in synoptic airflow patterns that govern pollutant transport. Sources of uncertainty include the degree of future climate change, future emissions of air pollutants and their precursors, and how population vulnerability may change in the future. Given these uncertainties, projections suggest that climate change will increase concentrations of tropospheric ozone, at least in high-income countries when precursor emissions are held constant, which would increase morbidity and mortality. Few projections are available for low- and middle-income countries. The evidence is less robust for PM, primarily because few studies have been conducted.
CONCLUSIONS: Additional research is needed to better understand the possible impacts of climate change on air pollution-related health impacts. If improved models continue to project higher ozone concentrations with climate change, then reducing greenhouse gas emissions would enhance the health of current and future generations.
KEY WORDS: air pollution, climate change, health impacts, ozone, particulate matter. Environ Health Perspect 116:1449-1455 (2008). doi:10.1289/ehp.11463 available via http://dx.doi.org/ [Online 10 July 2008]
Extensive literature documents the adverse health impacts of exposure to elevated concentrations of air pollutants, particularly ozone, particulate matter with aerodynamic diameters < 10 ([PM.sub.10]) and < 2.5 [micro]m ([PM.sub.2.5]), sulfur dioxide, nitrogen dioxide, carbon monoxide, and lead. Worldwide in the year 2000, 0.8 million deaths and 7.9 million disability-adjusted life-years lost from respiratory problems, lung disease, and cancer were attributed to urban air pollution (World Health Organization 2002).
Because the state of the atmosphere at various scales determines the development, transport, dispersion, and deposition of air pollutants, there is concern that climate change could affect the burden of illness and mortality associated with these gases and fine particles. Therefore, we review studies projecting the impacts of climate change on air quality and studies projecting the impacts of these changes on morbidity and mortality, with a focus on studies published since 2000. We limited our review to the past several years because of significant advances in climate modeling (Solomon et al. 2007).
Meteorology and Air Pollution
Air pollution concentrations are the result of interactions among local weather patterns, atmospheric circulation features, wind, topography, human activities (i.e., transport and coal-fired electricity generation), human responses to weather changes (i.e., the onset of cold or warm spells may increase heating and cooling needs and therefore energy needs), and other factors. Some locations, because of their general climate and topographic setting, are predisposed to poor air quality because the climate is conducive to chemical reactions leading to the transformation of emissions, and the topography restricts the dispersion of pollutants (Kossmann and Sturman 2004; Rappengluck et al. 1999).
Some air pollutants demonstrate clear seasonal cycles (Alvarez et al. …