Estimation of GHG Emissions from Diesel-based Freight Transport

Freight and passenger transport accounts for approximately one third of total transport greenhouse gas emissions. Emissions from vehicles need to be accurately estimated to ensure that the air quality management is implemented appropriately. At present, Pakistan is lack in proper measurement and estimation of vehicular emissions. This study provides a framework for development of GHG emissions inventory. This research aims at identification of procedures for estimation and monitoring of GHGs on road emissions, identification of significant pollutants from tailpipe emissions of diesel-based freight transport and to develop a relationship between vehicular emissions and speed. Emission data from four diesel buses were collected in Karachi. On-road measurements of vehicle emissions were acquired by using a portable instrument (IMR-۲۸۰۰). Exhaust emissions oxides of nitrogen (NOx) and carbon dioxide (CO۲) have been reported in this study. Statistical analysis provided that both pollutants have non-linear relationship with the vehicle speed. Tailpipe emission rate initially decreases with the increase in speed and then after reaching at the optimum speed,NOx and CO۲concentration increases with increase in speed. The methodology developed may be utilized for in-depth analysis of GHG emissions from diesel-based freight transport which contributes large portion of urban and infrastructure traffic.