Researchers found that reducing aerosol pollution can achieve both direct and indirect health benefits.

Atmospheric aerosols are tiny airborne particles that can dramatically affect the Earth’s climate through their influence on the flow of energy between Earth’s surface and space. Some aerosols have a cooling effect by reflecting solar energy back into space, while other aerosols containing substantial amounts of carbon warm their surroundings by absorbing the sun’s energy, and can also directly harm human health when particles are at ground level. The total impact of aerosols is a net global cooling effect, helping temper some of the warming caused by greenhouse gas emissions. Effects of efforts to reduce aerosol pollution could include increased warming and impacts on human health.

The impacts of aerosol cooling are not limited to changes in surface temperature. Aerosol direct effects (ADE) can reduce air flows from the Earth’s surface to the upper atmosphere that help flush out pollution, leading to a build-up of ground level pollution that negatively impacts human health. Researchers tested the health impacts of two aspects of ADE: effects on surface temperature and the effect of aerosol pollution on atmospheric stability. Researchers used a regional coupled climate-chemistry model (the Federally-supported Weather Research and Forecasting Model coupled with the Community Multiscale Air Quality model) and a community health assessment tool (Benefits Mapping and Analysis Program - Community Edition) to estimate effects using data from 1990–2010. This work was supported in part through an interagency agreement between DOE and EPA.

Average deaths arising from the effects of increased aerosol pollution in East Asia, North America, and Europe were estimated to be three to six times higher than reductions in deaths associated with temperature decreases due to aerosol cooling. ^[1] In other words, the health benefits from reducing aerosol pollution outweigh the health benefits of aerosol cooling. These results suggest that reducing aerosol pollution achieves both direct benefits on health and indirect benefits on health through changes in local climate that reduce harmful surface pollution.