CSE study: Vehicles key culprit behind pollution load
Gases such as nitrogen dioxide (NO2) and carbon monoxide (CO) have shown significant spikes in Delhi-NCR in a new analysis of early winter trends, surging with traffic emissions trapped under shallow winter boundary layers. These findings, experts said, point to the strong influence that traffic-related emissions have on Delhi’s daily pollution spikes. The analysis by the Centre for Science and Environment (CSE), released Monday, also noted that while peak pollution levels have been lower this early winter compared to previous years, the average pollution levels remain largely unchanged. The study, covering the period from October 1 to November 15, found PM2.5 rising and falling almost in tandem with NO2 during morning (7-10am) and evening (6-9pm) hours – a clear indication of the impact of traffic emissions and congestion. CSE said NO2 displayed sharper, more immediate peaks linked directly to vehicular plumes, while PM2.5 showed broader peaks as fine particles accumulated and dispersed more slowly. CO, which is also predominantly emitted from vehicles, showed widespread exceedances across Delhi this winter. More than half (22) monitoring stations recorded CO levels above the eight-hour standard on more than 30 of the 59 study days, pointing to persistent traffic-linked emissions. Delhi has a total of 40 air quality stations.
