Transportation Research Part D: Transport and Environment ( IF 7.3 ) Pub Date : 2021-01-18 , DOI: 10.1016/j.trd.2021.102705 Stephan Moonsammy , Temitope D. Timothy Oyedotun , Olayinka Oderinde , Mary Durojaiye , Abiodun Durojaye
The purpose of this study is to assess the exhaust emission levels of end-of-life automobiles in Ogun State, Nigeria and estimate the probability of compliance to European and national exhaust policy standards. Trend analysis, analysis of variance and binary logistic regression were used to compare emission levels and to estimate the probability of compliance to emission standards. The results showed that emission levels for carbon monoxide and oxygen increased by 2% and hydrocarbon levels doubled with the age of the vehicle. Older vehicles also show a lean mixture in the air to fuel ratio calculation. Vehicles falling within a heavier weight class emit more CO2. Probability models showed that compliance to European and national standards decrease as much as 30% with age and use of the vehicles. Older commercial vehicles falling into a heavy weight class has the lowest probability of compliance with any of the emissions policies assessed. The empirical evidence of the study supports the prior evidence that age, weight and use is directly related to emissions. With the volume of end-of-life vehicles in Nigeria, more enforcement is needed to monitor maintenance and increase vehicle compliance to emission policies.