Boston, April 4: Agricultural fires are to blame for about half of the pollution experienced in Delhi in October and November, a peak stubble-burning season in Punjab, a Harvard study has found using satellite data from NASA. For the past few years, every autumn New Delhi already plagued with thick pollution gets engulfed with choking smoke likened by many to a gas chamber.
While crop-burning has been illegal for years, there has not been a large enough deterrent to effectively crack down on the practice.
Researchers from Harvard University and NASA have now shown that in October and November, a peak burning season in Punjab, about half of all pollution in Delhi can be attributed to agricultural fires on some days.
“On certain days during peak fire season, air pollution in Delhi is about 20 times higher than the threshold for safe air as defined by the World Health Organisation (WHO),” said Daniel H Cusworth, a graduate student at SEAS and to model how much of that pollution is coming from the fires, the study published in the journal Environmental Research Letters, used satellite data from NASA to identify hotspots corresponding to active fires.
The team gathered available data for October and November, 2012 to 2016 and plugged it into a particle dispersion model an algorithm that accounts for geography, wind patterns, and physics to predict how far and in what direction smoke particles travel.
The WHO puts the threshold for safe air at 25 microgrammes per cubic metre, and the Central Pollution Control Board limits exposure to 60 microgrammes, said Cusworth.
Extreme fires during the post-monsoon season can pump on average about 150 microgrammes of fine particulate matter into the city, doubling the amount of pollution and increasing total levels 12 times higher than WHO recommendations and even 20 times higher on some days.
Source Tribune India
