Abstract
During 1990-1997, transportation consumed almost 60% of the total demand for petroleum products in the country. Diesel oil accounted for more than 60% of the petroleum products consumed in transportation.
Particulate matters are the most serious air pollutants in Bangkok. To reduce the emission, diesel fuel has been reformulated. As one of the main sources of suspended particulate matter, the Bangkok Mass Transit Authority buses should switch from diesel oil to compressed natu- ral gas.
With the introduction of unleaded gasoline in 1992 the amount of lead in the air is now much below the limit in the Thai air quality standard. Leaded gasoline has been removed from the Thai market since 1997.
To reduce the traffic congestion and air pollution in Bangkok, two mass transit systems are being implemented.