ABSTRACT: Vehicular emissions are the main ...

Vehicular emissions are the main contributor to urban air pollution. Recent years have seen social
demands for reduced automobile exhaust emissions and alternative fuels available from energy
resources. The impact of vehicular emissions can be considered in terms of health and environmental
risks; that the pollutants cause when introduced into the air (Morawska, 2003). Emissions of green
house gases (GHGs) are generally seen as a large problem since a temperature rise caused by the
increasing concentrations of GHGs in the atmosphere is likely to influence global climate (Hekkerta,
The use of natural gas as a transportation fuel can offer emissions and environmental benefits, energy
diversity and energy security. Natural gas (NG) is a mixture of difference gases which consists primarily
of methane with minor amounts of ethane, propane, butane and pentane. In many Natural gas
deposits, methane makes up to 80 to 90 percent of gas (Gas Malaysia Sdn. Bhd, 2003). It is a
hydrocarbon, which is colorless, odorless and much lighter than air.