High Resolution Transport Emission Inventory and Its Use in Locally Tailored Solution Strategies

Abstract

Transport sector is among the top air pollution contributors in the Indian cities. In this study, we present our work in developing a high-resolution on-road transportation emission inventory for the Indore city in India and developing a mitigation plan as part of the Clean Air Catalyst (CAC) program. The CAC program, led by WRI and EDF, aims to build capacity for local air pollution solutions through source apportionment and emission inventory. Transport sector emissions in the present study are estimated by using a combination of secondary and primary data. The secondary data available from various sources for the Indore city to generate a high-resolution emission inventory from the transport sector was the year wise vehicle registered, ward wise population, vehicle number at ward level. Data like purpose of travel, second- hand vehicle seller’s information, combined use of secondary and primary data to estimate the vehicle age are taken to reduce the uncertainty existing in the earlier methods, which helped in generating locally tailored emission inventory and solutions. To estimate Socio economic status (SES) and land use centric neighborhood emissions, a traffic count survey was also conducted to determine the number of different types of vehicles on the road in the Indore city. For conducting traffic vehicle count and Origin-Destination (OD) survey, six outer cordon points (OC) situated on highways outside the municipal limits were selected to understand the vehicle movement from the city to the outside and vice versa. Selected 11 inner cordon points (IC) inside the city covered all types of land use patterns, which represented roads from the residential settlement, commercial areas, industrial hubs, and mixed land use. These roads consisted of all types of road hierarchy comprising arterial (major roads), sub-arterial (connecting roads), local (minor roads), and highways which interconnect Indore into surrounding districts. The findings revealed that the transport sector along with road dust is the highest contributor in the Indore city, which is around 70% of the total PM2.5 emissions. The exhaust emissions in high SES wards ranges from 0.36- 40 MT/year, medium SES is from 0.13- 18 MT/yr, industrial regions is 0.015- 34 MT/year, and low SES from 0.6 – 54 MT/yr. Non exhaust emissions for high SES range from 1.3- 146 MT/year, medium SES 0.6- 63 MT/year, industrial regions 0.05- 121 MT/year and low SES range from 2.2- 194 MT/ year. These emissions were further used to design solutions for the transport sector at ward level. Pilot wards with high emissions were selected to implement locally tailored solutions designed for the city such as the low emission zones (LEZ), enhancing public transport service (PTS), scrapping of vintage vehicles and developing Infrastructure for NMT (sidewalks, bicycle lanes, and secure bicycle parking facilities, traffic calming to make NMT safe). The integrated approach of high-resolution emission inventory and locally tailored solutions can also be utilized in other areas/cities to address air pollution.