Estimation of high resolution emissions from road transport sector in a megacity Delhi

Estimation of spatially resolved traffic related emissions is important for exposure and health impact studies. However, this task is difficult for the megacities where detailed traffic related information is not available. In this work, we estimate the exhaust emissions of particular matter (PM), carbon monoxide (CO) and oxides of nitrogen (NOx) at a very high resolution of 100 sq.m from the road transport sector over a developing megacity Delhi for the year 2010. A total annual emission of PM, CO and NOx have been estimated to be equal to 4.5 Gg/year, 114 Gg/year and 51.5 Gg/year respectively. These estimates are relatively lower than earlier reported emission estimates. The highest emission per unit area is estimated in New Delhi district followed by East, North and Central districts. Major roads are estimated to be main source contributing more than 50% of the total emissions. HCVs contribute the most to the total emission of PM followed by LCVs and 2 Ws. Despite the large in number, cars contribute only 8% to the total PM due to the small emission factors. The biggest contributors to CO are cars and 2 Ws. Buses are the largest contributors of NOx followed by HCVs.