High up in the sky, it protects the Earth from getting torched. But closer to the ground, ozone seems to be adversely affecting productivity of several crops including rice and wheat.
In a unique and painstaking research, spanning over almost a decade, botanists at the Banaras Hindu University (BHU) have gathered evidence, suggesting that ozone pollution in rural areas has reduced productivity in rice, wheat, soya, mung. Adverse influences have also been observed in carrots and spinach.
“For mung and soya, the yield loss is between 15-20 per cent. For wheat, the loss is between 8-10 per cent, whereas for rice it’s about 20 per cent. For any crop, if the yield loss is more than five per cent, then it’s a cause for concern,” BHU botanist Dr Madhoolika Agrawal told Deccan Herald, on the sidelines of an international meeting on air pollution here.
Dr Agrawal first observed the disturbing trend near Singrauli in the early 1990s and later followed it up with laboratory and field studies near Banaras. The damaging effects are most visible in rural areas 20-40 kms away from Banaras city.
Ground level concentration of ozone is approximately 40 ppb (parts per billion) whereas the normal natural background ozone level should be between 8-10 ppb. The increase is due to a heightened amount of various oxides of nitrogen in the ambient air due to human activities. The oxides react with sunlight and produce harmful ozone.
Claiming that the Indian Council of Agriculture Research (ICAR) did not take note of the effects of ozone pollution on crops so far, Dr Agrawal theorised that similar trends are likely to happen in other parts of the country as well.
“BHU studies on the threat of the ozone stalling agricultural productivity are sporadic and limited in nature. One needs to carry out large scale trials to realistically assess the threat. Also, since ozone measurement is a difficult task, one needs to take utmost care in the measurement and instrument calibration,” Dr Dilip Biswas, former chairman of the Central Pollution Control Board told Deccan Herald commenting on the BHU findings.
However, Dr Agrawal claimed, her BHU laboratory is equipped to precisely measure the ozone level. Also she has asked the Department of Science and Technology to fund a bigger study covering more areas in Uttar Pradesh and Bihar to find out if the disturbing trend was visible elsewhere too.
“There are some similar reports from the USA and Europe where ozone’s harmful influences on crops have been seen in the country side. However, the measurement has to be accurate to arrive at any conclusion,” added Dr Daniel Greenbaum, president of the Health Effects Institute at Boston, who has reviewed the adverse effects of known pollutants for the US National Academy of Sciences.
