A study conducted by Stanford University found that due to falling air pollution levels, soybean and corn crop yields in the US saw an increase of 20% between 1999 and 2019 – an amount that would add $5bn to the industry every year.
The research, which was funded by NASA and the National Science Foundation, was published earlier this month in Environmental Research Letters. The findings could hopefully inform future technologies and practices to ensure steady crop yields.
“Air pollution impacts have been hard to measure in the past, because two farmers even just 10 miles apart can be facing very different air quality. By using satellites, we were able to measure very fine scale patterns and unpack the role of different pollutants,” said study lead author David Lobell in a Stanford press release. Lobell is the Gloria and Richard Kushel Director of the Center on Food Security and the Environment.
The satellites focused on nine states; Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Ohio, South Dakota and Wisconsin, which produce around two-thirds of the country’s maize and soybean output. In the course of the study, the impacts of ozone, particulate matter (such as dust or soot), nitrogen dioxide and sulphur dioxide on the crops were studied.
“This has been a tricky problem to untangle because historically our measurements of different types of air pollutants and our measurements of agricultural yields haven’t really overlapped spatially at the necessary resolution,” said study co-author Jennifer Burney, an associate professor of environmental science at the University of California, San Diego. “With the new high spatial resolution data, we could look at crop yields near both pollution monitors and known pollutant emissions sources. That revealed evidence of different magnitudes of negative impacts caused by different pollutants.”
The findings estimate that total yield loss for maize was an average of 5.8% and 3.8% for soybean in the period examined- losses that declined as the air got cleaner. The team point to the 1990 Clean Air Act as a pivotal moment in air quality beginning to improve.
“We already know that the Clean Air Act resulted in trillions of dollars of benefits in terms of human health, so I think of these billions in agricultural benefits as icing on the cake,” Lobell said. “But even if it’s a small part of the benefits of clear air, it has been a pretty big part of our ability to continue pushing agricultural productivity higher.”