The impacts of air pollution on human health, economies and agriculture differ drastically depending where on the planet the pollutants are emitted, according to a new study.
Led by scientists at The University of Texas at Austin and the University of California San Diego, the study, published in Science Advances, is the first to simulate how aerosol pollution affects both climate and air quality for locations around the globe.
Aerosols are tiny solid particles and liquid droplets that contribute to smog and are emitted from industrial factories, power plants and vehicle tailpipes. They impact human health, agriculture and economic productivity in unique global patterns when compared with carbon dioxide emissions, which are the focus of efforts to mitigate climate change.
Although CO2 and aerosols are often emitted at the same time during the combustion of fuel, the two substances behave differently in Earth's atmosphere, said co-lead author Geeta Persad of the UT Austin Jackson School of Geosciences.
"Carbon dioxide has the same impact on climate no matter who emits it," said Persad. "But for these aerosol pollutants, they tend to stay concentrated near where they're emitted, so the effect they have on the climate system is very patchy and very dependent on where they're coming from."
The researchers found that, depending on where they are emitted, aerosols can worsen the social costs of carbon — an estimate of the economic costs greenhouse gasses have on society — by as much as 66%. The scientists looked at eight key regions: Brazil, China, East Africa, Western Europe, India, Indonesia, the United States and South Africa.
"This research highlights how the harmful effects of our emissions are generally underestimated," said Jennifer Burney of UC San Diego, co-lead author. "CO2 is making the planet warmer, but it also gets emitted with a bunch of other compounds that impact people and plants directly and cause climate changes in their own right."
The work, which was supported by the U.S. National Science Foundation, is a collaboration among Persad and Burney, who are physical scientists, and economists and public health experts. Co-authors include Marshall Burke, Eran Bendavid and Sam Heft-Neal of Stanford University and Jonathan Proctor of Harvard University.
Aerosols can directly affect human health and the climate independently of CO2. They are associated with health impacts when inhaled, and can affect climate by influencing temperature, precipitation patterns and how much sunlight reaches the Earth's surface.