Environmental assessment of vehicle lubricants by life cycle assessment approach

Today pollutants related to refineries and base oil products have caused many concerns about environment. Among these, the share of lubricants as one of the oil products is undeniable for causing environmental problems, harmful pollutants for men and global warming. Recently LCA as a beneficial tool is provided for finding solution to the environmental problems. The aim of this study was to evaluate and compare environmental impacts of lubricants and its ingredients (oil based and additives). Additionally, it was attempted to identify the pollutants caused by the lubricants in order to replace them by environmentally friendly components. In this study, the system boundary was first identified and then the life cycle assessment steps were carried out for vehicle lubricants. Finally, the results were analyzed using SimaPro software based on the Eco Indicator 95. Results showed that although additives made up about 20 percent of the lubricants, more than 80 percent of the environmental pollutants were related to them. These materials have a significant impact on greenhouse gas emission and global warming as 91% of CO2 emission (7.81kg) of lubricants is related to the additives. Also, these materials emit 0.00913 kg C2H4 and 0.0368 kg SPM, which can make summer and winter smog. The car lubricants cause heavy metals (3.95×10-5 kg Pb) to be released into water and release of carcinogenic substances (4.2×10-6 kg B(a)P), which a very low percentage of it is allocated to base oil. The most important environmental pollution of vehicle lubricants was caused by the additives. Since the percentage of each additive to lubricants includes antioxidant (40%), antiwear (23%), detergents (20%) and viscosity modifier (17%), thus, the company must seek to change these types of additives and replace them with the components with lower environmental impact in their production cycles.