On Diwali eve, Air Quality Index (AQI) was recorded 310 µgm-3. Overall air quality in Delhi region was tagged in “poor” category but likely to slip in “very poor” category as forecast by SAFAR (System of Air Quality and Weather Forecasting And Research). 

Notably, air pollution monitoring agencies have forecast that this year Diwali may not be as bad as last year vis-a-vis air pollution, but it is pertinent to mention here that SAFAR has indentified 12 hot spots location where air quality graph may plunge to severe category, particularly the values of particulate matter (PM) 2.5.

According to SAFAR, these 12 locations where value of PM 2.5 will be recorded from 253.53 µgm-3 to 637.957 µgm-3 on Monday morning are  Asola wildlife sanctuary, Ayanangar airport T3, Narela, Gurugram, Dwaraka, Najafgarh, Lodhi Road, Jat Khor, Delhi University, Mundka , Rohini and Okhla.

SAFAR also highlighted stubble burning impact on Delhi’s air and said Haryana and Punjab fire counts are gradually increasing and following almost identical pattern as that of October 2018.

Citing the Meteorological (MeT) factors, the SAFAR said the surface winds are calm and variable with predominant direction from the east. The highest impact of firecracker emissions (if any) is expected in the early morning of October 28 (1 am-6am).

“ In a normal course, the stubble burning induced impact is expected to be moderate and if no additional emissions due to firecrackers are added then Air Quality will remain in the lower end of very poor during Diwali period (27th-28th Oct. 2019). However, if 50% of the total load of firecrackers (as compared to an average of Diwali-2017 & 18) is added, the AQI may plunge into severe category for a short period but with relatively much less magnitude (half) than 2018 Diwali period,” SAFAR said.

“Surface and boundary layer winds at present are from easterly direction but forecasted to change to northwesterly direction by late evening of 26th Oct which will have high potential to transport significant biomass in the coming days (10 to 25 percent) to the Delhi region only to be countered by not so calm surface winds until 28th October,” it said.

Inbox :

 Peak Pollution Timings

The peak levels of PM10 and PM2.5 are expected between 0100 hrs-0600 hrs on the night of 27-28, October.

Air Quality will be Severe on October 28 under the influence of firecrackers emissions  for a short period and start to improve thereafter.

Toxicity: Most striking factor is that share of PM2.5 (relatively more harmful) in PM10 will increase by ~15% if any firecracker emissions are added.

(4)  Key Parameters:

1 Wind Speed - If remain calm then it will drastically deteriorate the Air Quality (Very unlikely) 2 Onset of Westerly disturbances with Shower (Unlikely) to significantly improve the air. Most Polluted Locations: Southeasterly - Favorable.  Least Polluted Locations: Gurgaon, Ayanagar, Nahru Stadium.  Bio-mass Share :Likely to increase on October 27 and then from October 29.