Overview of biodiesel combustion in mitigating the adverse impacts of engine emissions on the sustainable human–environment scenario

Air pollution is a precursor to many health issues such as difficulty breathing, asthma, lung and heart diseases, and cancer. This study presents a concise view of biodiesel combustion in mitigating pollutant emissions which are generated by the combustion of fossil fuels, thereby eliminating the negative effects on human health and the environment. Gaseous pollutants such as carbon monoxide, unburned hydrocarbons, nitrogen oxides, particulate matter, and carbon dioxide are found to be major exhaust emissions from vehicles running on fossil fuels. Excessive exposure to these pollutants was found to be a precursor to reductions in life expectancy via health complications in humans. Greenhouse gas emissions from the transport sector were found to be 24% of total annual emissions, 74.5% of which came from the combustion of fossil fuel in road vehicles. Biodiesel combustion in vehicular engines is established to be a control technology in reducing gaseous pollutants toward building a sustainable and healthy human–environment scenario. The emissions reduction index from the United States National Biodiesel Board showed that the combustion of biodiesel wholly as a transportation fuel decreased total hydrocarbons, polycyclic aromatic hydrocarbons, carbon, and sulfur emissions by 67%, 80%, 48%, and 100%, respectively. Evaluation of emission results from topical literature strongly suggests that the use of biodiesel is effective in the reduction in pollutants, which is beneficial to human and environmental sustainability.