Air, Soil and Water Research

Dynamic emission factors of air toxic compounds, emitted from vehicles in Bangkok, Thailand, are developed using the IVE model. The model takes into account the actual fleet and characteristics of vehicles in the study area. It is found that the calculated emission factors are greatly influenced by vehicle emission control policy. Approximately 2000 tons of benzene emission per year is reduced by the changing of fuel quality from Euro 2 to Euro 4 standards. As for mitigation measures, introduction of gasohol and natural gas as alternative fuels, as well as encouraging the utilization of public transportation systems, are analyzed. The outcomes reveal that a combined scenario using 100% gasohol plus decreasing vehicle kilometers traveled (VKT) by 20% is the most effective in reduction of benzene emission. In addition, 1,3-butadiene, acetaldehyde and formaldehyde emissions are greatly decreased by the combined scenario of using compressed natural gas (CNG) plus decreasing VKT by 20%.