Vehicular emissions biggest contributor to pollution levels in Delhi: Analysis

Delhi air pollution: Although there are many factors responsible for the pollution level in Delhi, vehicular emissions are said to be the biggest contributor to Delhi’s PM 2.5 levels, in terms of local sources of pollution. This analysis came from the Centres for Science and Environment (CSE) and is based on data for every alternate hour from october 24 to November 8.

The data is sourced from the Decision Support System (DSS) developed by the Indian Institute of Tropical Meteorology, Pune. It has been analysed to determine different sources of pollution levels responsible for pollution in Delhi.

The CSE analysis noted that vehicles contribution has been half or more during the study period. Anumita Roychowdhury, executive director, Research and Advocacy, CSE, who was part of the team that carried out the analysis said this figure would be around 50-53 per cent.

As per the analysis, the contribution of household pollution stood at 12.5-13.5 per cent and of industry’s, it stood at 9.9-13.7 per cent. The contribution of construction stood at 6.7-7.9 per cent while waste burning pollution was at 4.6-4.9 per cent. The contribution of road dust stood at 3.6-4.1 per cent.

The biomass burning pollution from other states remained low during pre-Diwali times but soared post Diwali. Transport winds also brought in pollutants from biomass burning in other states. The analysis also noted that nitrogen dioxide levels increase in the environment when traffic congestion increases, and travel speed reduces.

On November 5, the NO2 level was close to 70 µg/m3 between 6 pm and 7 pm, up from 40 µg/m3, between 2 pm and 3 pm. Peak hours in the evening in Delhi NCR are usually between 6 pm and 8 pm. Google Map data was analysed for 15 major roads in Delhi and the travel time and speed along these roads.