Minimizing common air pollutant could lead to better crop yields: study

Eliminating one common air pollutant from the atmosphere could lead to considerable gains in agricultural production, a new study has found.

Nitrogen oxides — gases found in car exhaust and industrial emissions — pose a significant threat to global crop yields, according to a report in Science Advances, published on Wednesday.

These findings, uncovered through satellite imagery, could have significant implications for boosting agricultural output and determining climate change mitigation costs, the authors wrote.

“Nitrogen oxides are invisible to humans, but new satellites have been able to map them with incredibly high precision,” study lead author David Lobell, of Stanford University’s Center on Food Security and the Environment, said in a statement.

“Since we can also measure crop production from space, this opened up the chance to rapidly improve our knowledge of how these gases affect agriculture in different regions,” Lobell added.

While scientists have long recognized the potential of nitrogen oxides to be damaging, little was understood about their actual effects on crop yields, the authors wrote.

Nitrogen oxides can both directly damage crop cells and indirectly impact them through their role as precursors to the generation of ozone, according to the study. Ozone is an airborne toxin known to hamper crop success.  

Past research into the impact of nitrogen oxides on agricultural productivity has been limited by a lack of overlap between air monitoring stations and farmlands, as well as the confounding effect of other pollutants, according to the authors.

To minimize these obstacles, Lobell and his colleagues looked at both satellite measurements of crop greenness and levels of nitrogen dioxide — a good indicator for total nitrogen oxides — for 2018 to 2020.

Based on their observations, the researchers estimated that reducing nitrogen oxide emissions by about half would improve yields by about 25 percent for winter crops and 15 percent for summer crops in China.

Doing so would improve yields by 10 percent for both winter and summer crops in Western Europe, as well as 6 percent for winter crops and 8 percent for summer crops in India, according to the study.

North America generally demonstrated the lowest nitrogen oxide exposures, the authors found.

Actions that could help decrease nitrogen oxide emissions — like vehicle electrification — are in line with those “needed to slow climate change and improve local air quality for human health,” co-author Jennifer Burney, an associate professor of environmental science at the University of California, San Diego said in a statement.

“The main take-home from this study is that the agricultural benefits of these actions could be really substantial, enough to help ease the challenge of feeding a growing population,” Burney added.