Differentiating Climate Change and Emissions Influence on Future Ozone and Health

Abstract:

From the advent of coal burning and the subsequent industrial revolution to the present, human activities continue to influence ground-level ozone (O₃) concentrations. Besides the obvious environmental and climate implications, studies have shown convincing links between O₃ exposure and health. These adverse health outcomes range from impaired lung function and cardiovascular stress to premature death. However, little is known concerning the potential impacts of future mitigation policies on O₃ and health. Applying novel modeling strategies, we provide evidence of the impact of mitigation on O₃ attributable to both climate change and anthropogenic emissions. We employ the latest emission scenarios for both low and high emissions (Representative Concentration Pathways or RCPs) and include population projections to estimate excess mortality associated with each source separate from one another. We found that, by the mid-21^st century, U.S. O₃ could increase by 0.9% per year under a low emission future and by 1.6% under high emission settings. We predict excess mortality from high emission-induced O₃ to increase annually by over 1,200 deaths. Conversely, excess deaths from lower emissions may decrease by over 1,600 annually. Taken together, these results indicate that mitigation efforts may significantly offset the effect of climate change on O₃-related mortality.