New Delhi, Nov 12 Biomass burning and secondary organic aerosols emerged as the primary contributors to Delhi’s air pollution on Thursday, accounting for 25.4 per cent each of the city’s pollution load, according to source-apportionment estimates by the Indian Institute of Tropical Meteorology (IITM).
Vehicular emissions were the third-largest source, contributing 17 per cent, while secondary inorganic aerosols accounted for 11.8 per cent of the pollution load.
Within secondary inorganic aerosols, nitrate contributed 4.9 per cent, ammonia 4.1 per cent and sulphate 2.9 per cent.
Mixed combustion accounted for 10.7 per cent of the pollution, followed by firecrackers at 7.1 per cent. Waste burning, including municipal and plastic-rubber containing waste, contributed 1.5 per cent, while mineral dust and ash accounted for 0.9 per cent and industrial emissions 0.2 per cent.
Experts said secondary organic aerosols are formed through chemical reactions in the atmosphere and can originate from emissions linked to certain industries, diesel and petrol vehicles, and biomass burning.
A thick, sepia-coloured haze shrouded the national capital on Thursday, blurring its skyline and leaving residents coughing, with burning eyes and gasping for breath, as the city’s air quality deteriorated further, underscoring the growing public health crisis.
As protests demanding the basic right to clean air continued across the city, Delhi’s 24-hour average Air Quality Index (AQI) climbed to 350, firmly in the ‘very poor’ category, from 313 recorded on Wednesday.
Of the 57 air quality monitoring stations that recorded data on Thursday, 10 were in the ‘severe’ category, 42 in the ‘very poor’ category, four in the ‘poor’ category and only one in the ‘moderate’ category.
An AQI between 201 and 300 is classified as ‘poor’, while readings between 301 and 400 fall in the ‘very poor’ category.
The contribution of firecrackers, which had emerged as the biggest source on Monday and Tuesday following Diwali, dropped sharply to 7.1 per cent on Thursday.
Firecrackers accounted for 71.1 per cent of Delhi’s pollution load on Monday and 29.8 per cent on Tuesday, before falling to 7.4 per cent on Wednesday.
According to the Decision Support System (DSS) for Delhi, the transport sector’s contribution is projected to rise to 18.5 per cent on Friday, which is also expected to become the primary contributor to Friday’s pollution.
(PTI News)
