The national Capital registered air quality falling once again in the ‘severe’ category on Monday morning as several areas in Delhi recorded AQI over the 400 mark. Some localities saw AQI less than 400. The current PM2.5 concentration in New Delhi is 16 times above the recommended limit given by the WHO 24 hrs air quality guidelines value.

According to a study by IIT Kanpur, IIT Delhi and TERI who are involved with the real-time source apportionment study has highlighted biomass burning, secondary aerosols and vehicles as some of the main contributors to the worrying air quality of the national capital in November this year. 

The data showed that PM 2.5 have been contributing major chunk to the pollution in the national Capital.

The secondary aerosol, which are particles such as sulfate, nitrate, ammonium formed in the atmosphere from the interaction of various gases. The secondary aerosol potential sources include powerplants, refineries, brick kilns, vehicles, industry, agriculture, organic waste decomposition, and open drains.

According to the portal on real-time source apportionment, the share of secondary inorganic aerosols to PM2.5 was 36 per cent on November 23, while next day it came down to 23 per cent and once again spiked to 29 per cent on November 25 and on November 26 it was 26 per cent.

According to the portal, the share of vehicles, which consists of the off and on-road vehicles, petrol, diesel, CNG-powered vehicles, and diesel generator sets to PM2.5 was 22 per cent on November 23, 26 per cent on 24 November, 24 per cent on November 25 and 29 per cent on November 26. Going by the portal, the share of biomass burning, which includes wood, dung, agriculture residue, and plant branches and leaves to PM2.5 was 27 per cent on November 23, 40 per cent on November 24, 37 per cent on November 25 and 30 per cent on November 26.

The study project was started by the Delhi Pollution Control Committee in collaboration with IIT Kanpur, IIT Delhi and TERI.

Meanwhile, the overall air quality in Delhi continues to be in the ‘very poor’ category with the AQI at 369 on Monday evening, according to data from the System of Air Quality and Weather Forecasting And Research (SAFAR).