eng Science and Education Publishing Applied Ecology and Environmental Sciences 2328-3920 2022-05-08 10 5 273 280 10.12691/aees-10-5-2 AEES20221052 article Sanu Meena sanu.iitb@gmail.com 1 Suresh Kumar Singh 1 Department of Civil Engineering, M.B.M. University, Jodhpur 342011 Rajasthan, India Vehicles contribute significant emissions in urban areas affecting the air quality of cities. Traditionally, vehicular emission factors (EFs) were developed based on measurements in the laboratory. However, studies indicate that the laboratory measurements are unrepresentative of real-world conditions. This study reviewed the literature on emission measurements of vehicles using Portable Emission Measurement Systems. The on-road emissions measurements were able to capture the emission characteristics during the micro events of real world driving scenarios which were not represented by standard vehicle emission measured at laboratory conditions. The current emission factors recommended by regulatory agencies like ARAI are laboratory based which were found to be under estimate the real world emissions. Compared to other measurement methods, such as dynamometer testing, on-board real time emission measurement provides detailed data that can be used to identify real-world estimates at micro scale events that significantly impact overall emissions. Accurate prediction of vehicular exhaust emissions is an important factor in predicting air quality in urban area which assists in policy and decision making process. http://pubs.sciepub.com/aees/10/5/2/aees-10-5-2.pdf real driving emissions emission factor portable emission measurement systems