New Delhi: After a day of breathing easy, the air quality again turned ‘poor’ by Monday evening in the national capital.
However, the concentration of ultrafine pollutants —PM (Particulate Matter) 10 and PM 2.5 — in Delhi’s air was considerably lower when compared to last few days.
Scientists at Safar, under Union ministry of earth sciences, monitoring the pollution levels said that the main reason behind this was strong winds which is unusual given that fog is occurring and temperatures are falling during this part of the season.
While the air quality index (AQI) on Monday was at 234, in the ‘poor’ category, the values for PM 10 and PM 2.5 were at 147 and 84 microgramme per cubic metre (ug/m3) respectively, slightly higher than their prescribed standard of 100 and 60 ug/m3 but in the ‘moderate’ category.
“The values have improved because of an unusual trend of wind speed of more than 10 km/hour in the last couple of days even as the temperatures are falling and fog is occurring in the city. Generally fog is associated with calm winds but this time the combination of low temperatures and high wind speed is rare and good for air quality,” said Dr Gufran Beig, Project Director, Safar (System of Air Quality and Weather Forecasting and Research).
On Sunday, after a long gap, people of the National Capital Region got to breathe easy as the air quality index was in the ‘moderate’ category, at 198. The minimum and maximum temperatures on Monday were recorded at 9.8 and 25.6ºC respectively.
