Air clean-up act: PM10 out of emergency levels, PM2.5 to follow soon
Met officials said surface level winds, which would help to flush out pollutants from Delhi’s air, are likely to pick up speed during the day.delhi Updated: Nov 11, 2017 10:35 IST
Delhi’s air quality appeared to be improving on Saturday as a haze over the capital started to disperse overnight, bringing down pollution levels considerably after three days of extreme conditions, officials said.
The air quality index (AQI) –a measure of harmful particulate matter in air – dropped to 416 at around 7.30 am on Saturday from the average 468 on Friday. The Central Pollution Control Board says a reading above 100 is unhealthy.
On Thursday, at some places the AQI had touched 499 on a scale where the maximum reading is 500. The AQI before the haze engulfed Delhi since Tuesday night was 350.
“While the level of PM10 has already dropped below the emergency levels, the level of PM2.5 is still in that zone. It is, however, dropping with every passing minute and we expect to come out of severe+ levels within the next few hours,” said a senior CPCB official.
CPCB data showed PM10 level, which was hovering above 880 micrograms per cubic meter air on Wednesday night and Thursday morning, stood at 470 at 7.30 am on Saturday. One microgram is one-millionth of a gram. PM10 values above 500 denote emergency levels.
Similarly, PM2.5 levels, which had crossed 600 on Wednesday night, came down to 319 on Saturday morning. PM2.5 values above 300 denote emergency levels.
PM 2.5, about 30 times finer than a human hair, are considered more harmful to humans as the pollutants can penetrate deep into the lungs and cause severe diseases.
“The situation has improved significantly compared to what it was on Tuesday and Wednesday. We are expecting further improvements today and on Sunday,” said a senior official of the regional weather forecasting centre.
Met officials said surface level winds, which would help to flush out pollutants from Delhi’s air, are likely to pick up speed during the day.
In the meantime, the speed of high-altitude wind that were bringing in pollutants from west Asia and stubble burning regions of Punjab and Haryana was decreasing, they said.
Experts said that with pollution levels dropping fast, the air quality of Delhi could return to pre-haze levels by Sunday night.
The severe pollution has prompted the Delhi government to order a raft of emergeny measures including closing down schools, suspending construction activities and implementation of a controversial road rationing scheme known as “odd-even”.