So far, crop fires to blame for just 2% of PM2.5 load
New Delhi: While NASA imagery shows a spurt in crop stubble burning in the last 24 hours, Delhi is yet to be significantly affected by it. In fact, farm fires contributed just 2% to Delhi’s overall PM2.5 concentration on Saturday, any analysis by System of Air Quality and Weather Forecasting And Research (SAFAR) showed.
But don’t rejoice yet: things are expected to worsen gradually and the contribution of crop stubble burning to Delhi’s PM2.5 is likely to touch 6% by Tuesday. Despite little foreign influx, Delhi’s air quality has been deteriorating over the last three days — an AQI reading of 222 (poor) on Saturday was slightly worse than Friday’s 216.
“The overall air quality of Delhi is in the poor category, as forecasted. Southwest monsoon has withdrawn from most of northwest India and the increased biomass fire activity in Haryana and Punjab may now start to influence Delhi’s AQI,” SAFAR, which is a body of the ministry of sciences, said in a statement.
It said a spike in crop burning in Punjab and Haryana over the next few days, coupled with the weather conditions, could worsen things a little. “The surface wind speed continues to be low and variable, and is predominantly from the west. Under these conditions, air quality is predicted to deteriorate to the middle of the poor category by Sunday. While a further deterioration is expected by October 14, AQI is still much better this time around than in the last few years, partly because of the moisture with relatively warmer temperatures around Delhi,” SAFAR stated.
Delhi's air quality was “satisfactory” till October 2 and “moderate” till October 9. It turned poor for the first time in the season on Thursday. “Last year, the city's air quality had turned very poor on October 7,” an official said.
While Delhi’s average PM10 concentration on Saturday was 179 μg/m3, SAFAR’s three-day forecast showed it could touch 215 μg/m3. Similarly, the average PM 2.5 concentration, which was 97μg/ m3 on Saturday, is expected to touch 116μg/m3 after three days. The safe standard for these ultrafine particles is 100 and 60μg/m3, respectively.
A Met department official said low wind speed was not allowing local emissions to disperse freely and similar conditions were expected over the next few days. “There will not be a significant change in the temperatures, but wind speeds will continue to remain low. The westerlynorthwesterly winds are starting to bring stubble burning into the picture and this will increase in the coming days,” the official said.