The air quality of Delhi is likely to spike to “severe” category in the wee hours of Monday due to the effect of firecrackers on Diwali night. But it will be for a short period with about “half” the magnitude of Diwali in 2018 , according to government-run monitoring agency, System of Air Quality and Weather Forecasting and Research (SAFAR).
The level of PM2.5 (deadly respirable fine particles) is also expected to be less on Monday, a day after Diwali, than in the last three years.
“Higher boundary layer winds are likely to flush out the expected high impact of firecracker emissions,” SAFAR said.
Meanwhile, the air quality of Delhi on Friday improved slightly to the upper end of “poor” category but is expected to fall to “very poor” category on Sunday. The Air Quality Index (AQI) was 284 on Friday, slightly lower than 311 on Thursday.
“The highest impact of firecracker emissions is expected in the early morning of October 24 [1 a.m.- 6 a.m.]. In a normal course, the stubble burning induced impact is expected to be moderate,” SAFAR said.
The boundary layer and surface winds are likely to intensify by October 27 and may sustain for the next two days, which will not allow accumulation of pollutants due to stubble burning, said SAFAR.
Less emission
SAFAR had considered two scenarios in its Diwali prediction: First, zero firecracker emissions and second, 50% of average firecracker emission of 2017 and 2018.
Under the first condition, the AQI will remain in “very poor” category on Monday and under the second it will spike to “severe”, but the second condition is more likely to happen.
“We considered 50% of the average emission of 2017 and 2018 as only green crackers are allowed this year and their emissions are lesser by about 30-40%. On top of that due to increased awareness, we expect a dip of about 10% in use of firecrackers and hence the emissions are expected to be 50% less than last two years,” a SAFAR official told The Hindu .
But, SAFAR also cautioned that pollution could be higher. “Combination of several rapidly changing weather parameters play a role in controlling the air pollution at this time and dynamics changes, even if one parameters behaves erratically,” it said.
