State of the Planet

News from the Columbia Climate School

Aging Populations, Low Economic Development May Amplify Future Air Pollution Health Impacts

Brick kilns near Dhaka, Bangladesh. (Kevin Krajick/Earth Institute)

Population aging and economic development drawbacks may increase premature deaths from fine-particulate pollution in some regions even if the planet sees less overall pollution and climate change is slowed, according to a new study in the journal Nature Sustainability.

“When we think about the pollution impacts on future populations, exposure to ambient particulate matter caused by fossil fuel emissions is the greatest threat to global health,” said principal investigator Wei Peng of the Penn State College of Engineering. “The health burden is unevenly distributed across countries and disproportionately borne by the global south.”

The researchers came up with five possible scenarios for future health impacts by integrating data from the World Climate Research Programme’s Scenario Model Intercomparison Project with the National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory They estimated how changing socioeconomic trends and climate mitigation efforts may influence global fossil fuel use and resulting air quality.

The resulting model estimated pollution exposure levels and the number of premature deaths with varying values of pollution control, socioeconomic trends and climate warming from 2015 to 2100. In all five scenarios, researchers found countries and regions that limited emissions and had declining fossil fuel use had lower pollution concentrations.

However, lower pollution concentrations alone did not necessarily lower the projected number of deaths. According to the study, aging and declining baseline mortality—the natural death rate unrelated to air pollution—were better predictors of premature deaths than exposure to air pollution alone.

“Emerging markets like China and India contribute to less than half of the global carbon emissions, but they suffer from 60 percent of the world’s health damage due to air pollution,” said Hui Yang, a Penn State doctoral student and first author on the paper. “That is partly because they do not have sufficient end-of-pipe controls, or effective regulations controlling how much emissions industries can release to the air.”

In most future scenarios, China and India account for the highest estimated premature death numbers, researchers found. Peng said this is likely the result of higher rates of exposure due to the lack of controls, combined with an aging population that is more vulnerable to pollution exposure.

“Areas with unsatisfying socioeconomic conditions and limited access to health care tend to have higher baseline mortality rates,” Peng said. “If you couple that with an aging population, death rates go up. If we do more to clean the air and put limits on emissions, we have a chance to have a different future, to fight against some of the negative health effects of socio-demographic changes coming our way.”

Co-author Daniel Westervelt, a research professor at the Columbia Climate School’s Lamont-Doherty Earth Observatory said that the modeling framework can inform societies’ next steps in mitigating the impacts of air pollution. “Understanding the potential pathways of future air pollution and associated health burden using earth system models is critical for crafting effective mitigation strategies,” he said. “This work sheds new light on untangling the impacts of emissions, climate change, exposure levels and socio-demographic factors in determining the future health burden from air pollution.”

Other co-authors include Xinyuan Huang of Penn State and Larry Horowitz of the National Oceanic and Atmospheric Administration. The U.S. National Science Foundation and a seed grant from the Penn State-Monash Collaboration Development Fund supported the research.

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