High concentration of ultrafine particles in the air, which can “increase the risk of cancer”, was found in Delhi-NCR in the days before and after Diwali by a NASA-funded research.
Analysis of data from 35 PurpleAir sensors in a radius of 200 km from Delhi found that the concentration of particulate matter of size one micrometres (PM1) increased from 100 µg/m3 in September to 200-300 µg/m3 in one month from October 15.
The data was analysed by Palak Balyan from the IIT Delhi,
A P Dimri from JNU and S K Dhaka from DU, who emphasised on the need to monitor PM1, which presently does not have an exposure limit in India unlike PM2.5 and PM10. Balyan said, “PM1 can impact our health more by reaching deeper into our lungs.”
Concentration of PM2.5, which has a 24-hour exposure limit of 60 µg/m3, was found to be close to 1,000 µg/m3 on November 10 and around 700 µg/m3 on November 14.
While the analysis attributed this spike in PM2.5 to mainly crop residue burning in Punjab and Haryana, it also stated that high humidity and low temperature cause smaller PM1 particles to merge and form secondary particles of larger size. Professor Arun Sharma of the University College of Medical Sciences, DU, said, “Particles of size 1 micron or less are more harmful as they can cross the mucus barrier and, through blood circulation, reach any organ and cause damage or increase the risk of cancer.”
As per the analysis, composition of PM1 and smaller particles mainly “contain trace elements” that create a “carcinogenic risk”.
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