Odd-even formula: Air quality New Delhi, Jan 1: Air quality remained very poor. But the reduction in PM 2.5, possibly around 15 per cent due to less emissions and vehicular dust reduction, that was observed for few hours could be seen as an impact of the odd-even measure as other factors like wind speed and temperature remained the same as last two days.
Particulate matter is the general term used for a mixture of solid particles and liquid droplets in the air. It includes aerosols, smoke, fumes, dust, ash and pollen.
Possibly due to the odd-even restrictions and holiday. Pollutants in the city’s air dipped by around 10 per cent on average between 8 AM to 2 PM today compared to the last two days, before rising sharply afterwards with a fall in day time temperature.
As per initial observations of System of Air Quality and Weather Forecasting and Research (SAFAR), the gains of less vehicular emissions could have been more had there been less vehicular movement and no bursting of firecrackers on the night of January 31.
Although the average value of suspended particulate matter PM 2.5 rose to around 198 micrograms per cubic metre, an increase as compared to yesterday, a fall could be observed between 8 AM when the odd-even scheme kicked in and 2 PM, SAFAR’s Project Director Gufran Beig said.
“It is still premature to conclude anything with just 10 hours available for comparison,” he said in a statement.
(SAFAR) had yesterday said that air quality in Delhi was expected to deteriorate over the next few days with a possible rise in the level of particulate matter due to fall in minimum temperature and calm wind movement.
Officials said the air quality remained “very poor” today due to atmospheric conditions that did not allow pollutants to get dispersed.
While a section of the ruling AAP attributed the sharp drop in PM 2.5 figures between early morning hours and afternoon to the car rationing experiment, scientists said pollutants usually touch their peak in the dawn and then gradually fall.
SAFAR stations, located in various areas the city, displayed ‘very poor’ real-time Air Quality Index, which was in line with the forecast of the Union government body that was released yesterday.
In no marked change from yesterday, the average levels of PM 2.5 was around 180 microgrammes per cubic metre, three times above the safe limit of 60. The corresponding safe limit of PM 10 is 100.
Central Pollution Control Board’s real time AQI for the Punjabi Bagh, R K Puram, NSIT Dwarka and Anand Vihar stations were ‘severe’ at 5 PM. Air quality is considered ‘very poor’ by Indian authorities when level of PM 2.5 ranges from 120 to 250 microgrammes per cubic metre.
source : PTI