After days of soaring levels of pollution, air quality in Delhi improved slightly from “severe” to “very poor” category with Air Quality Index (AQI) 367 on Tuesday.
This was the first time when levels of Suspended Particulate Matters (SPMs) — PM10 and PM 2.5 recorded “poor” and “very poor” with 278 and 193 counts respectively on the National Ambient Air Quality Index (NAAQI).
According to System of Air Quality and Weather Forecasting and Research (SAFAR), air quality will improve further on November 8 due to fresh Western Disturbance (WD).
“A fresh WD is approaching north India; change in surface and boundary layer direction is expecting by early November 7, this will reduce stubble fire plume transport. Scattered rainfall is expected to further improve AQI to the lower end of very poor to poor category by 8th November,” SAFAR said.
Interestingly, environment experts and scientists observed that the number of biomass fire incidents on Monday was 4,962, but due to favourable north-western wind direction, Delhi air quality was least affected and continued to recover.
“This is an illustrative example that how the combination of several factors like external transport, local emission, and boundary layer dynamics has to act together to have a powerful impact,” the MoES scientist said.
Secondary particles, which has been formed after light rain on Sunday, are product of complicated atmospheric reactions between primary particles — such as particulate matter, sulphur dioxide and nitrogen dioxide directly emitted by stubble burning and vehicles — in the presence of other factors such as sunlight and moisture.
Meanwhile air quality is expected to remain under poor category after November 7. According to Central Pollution Control Board (CPCB), AQI in Delhi recorded far better than that in neighbouring States.
While overall AQI in Delhi improved from “severe” to “very poor” but in isolated pockets e.g, Dwarka, Anand Vihar and Punjbai Bagh, PM 10 was recorded in “severe plus” category — 768, 550 and 309 respectively.
In the National Capital Region, Greater Noida had AQI 348, Noida 358, Ghaziabad 351, Faridabad 311 and Gurgaon 328 also recorded improvement in air quality.
