Cutting air pollution could boost crop yields by up to 28 per cent

Slashing nitrogen dioxide emissions to 5 per cent of current levels could increase crop yields in China by up to 28 per cent. Limiting this type of air pollution would also improve crop yields in other regions of the world.

“China continues to see some of the highest nitrogen oxide levels in the seasons and places where crops are growing,” says David Lobell at Stanford University in California.

There are two main ways nitrogen oxides affect crop yields, he says. “Nitrogen oxide is a phytotoxin, meaning it directly damages plant cells. But it is also a key factor in the formation of other pollutants such as ozone, which are themselves damaging to plants.”

To quantify the effects of this potent greenhouse gas on crops, Lobell and his colleagues analysed satellite images of crops in the US, China, India, western Europe and South America between 2018 and 2020.

They rated how green the images were, as previous studies had found that crop greenness measured using satellites is strongly linking to crop growth and yield. They then compared this rating with each region’s nitrogen dioxide levels, taken from satellite data that can track the gas’s unique spectral signature. Lobell says nitrogen dioxide is a good measure of the levels of nitrogen oxides, a group of highly reactive gases.