Air pollution by coal-fired plant causes yield loss for rice and wheat: Study

New Delhi: While dangerous consequences of air pollution on the health are known, a new study on Monday reported up to 10 per cent yield loss for rice and wheat in several states due to the pollution caused by coal fired power plants.

The study by the Stanford University researchers found an adverse impact of air pollution on crops up to a distance of 100 km from the power plant.

They estimated that the productivity loss would amount to over $ 400 million every year for each of the two crops.

Although the effects of air pollution on human health and mortality are known, the effects on rice and wheat crops, important to India’s food security, remain unclear, prompting the scientists to examine the problem.

The Stanford team looked at the impact of nitrogen dioxide, a key component of emissions released by coal-fired power plants, a major source of air pollution.

The researchers quantified rice and wheat yield losses associated with coal power stations’ nitrogen dioxide emissions using detailed generation and wind direction data, and satellite measures of nitrogen dioxide and crop productivity.

“In parts of West Bengal, Madhya Pradesh, and Uttar Pradesh heavily exposed to coal-linked nitrogen dioxide, annual yield losses exceed 10 per cent, equivalent to approximately six year worth of average annual yield growth in both rice and wheat in India between 2011 and 2020,” they reported in the Proceedings of the National Academy of Sciences.

While examining the pollutant levels for two seasons, they found that the mean nitrogen dioxide level is 20 micromolar per cubic meter in southern states like Tamil Nadu, Karnataka and Andhra Pradesh in Sept-Oct, but rose to 40 micromolar in Chhattisgarh and Haryana.

In the winter months (Jan-Feb), the average concentration is high everywhere. In southern India, the level is 27 micromolar, but the figure rises to 40 micromolar in the Indo-Gangetic plains and shoots up to over 60 micromolar in parts of West Bengal, Odisha and Chhattisgarh.

According to their modelling, yield improvements of more than 10 per cent are expected for the rice in western West Bengal and south-eastern Uttar Pradesh, while for the wheat crop in south-eastern Uttar Pradesh and eastern Madhya Pradesh. Yield gains of over 5 per cent are expected in several areas near coal power stations.

The researchers further noted that nitrogen dioxide alone didn’t capture the full extent of crop loss due to air pollution in India because the gas is the precursor of ozone, which is also known to cause significant yield loss for both wheat and rice.

“Improved crop productivity is an important co-benefit of reducing coal pollution in India,” they reported.