State of the Art on Vehicular Engine Exhaust Emissions Standards and Regulations: a Review

. Burning fossil fuels introduced massive quantities of pollutants, leading to many adverse effects on human health. Therefore, regulations to reduce or eliminate exhaust gases and pollutants emissions from fossil fuels began to be issued worldwide in 1970. Automotive emissions issue has been strictly regulated since 1980. Therefore, this article reviewed some significant countries' vehicular emission standards for diesel and gasoline engines. The review began with an overview of considerable diesel and gasoline exhaust emissions, how they are generated, and their impact on the environment and human health, then surveyed the emission standards and regulations for motor vehicles in the United States, Europe, Japan, Australia, China, India and Nigeria. This section discovered that most countries have modelled their regulatory standards using the European and US regulatory models. Since Countries like Japan and Europe have already been following the worldwide harmonised test cycle to rectify the differences in present emission standards followed by different countries, more concerted research is needed for evolution to a shared universal emission standard implementable worldwide so that other countries may introduce the same shortly. Policies to discourage growth in personal automobile use are also potentially most significant. Thus, the review herein has been discussed to have better insight into the status of existing vehicular emission standards, which may be helpful for future improvisation and implementation of vehicular emission standards in Nigeria