During the last decade, the very rapid traffic growth in Bangkok, Thailand, has led to rising exhaust emissions of lead, suspended particulates, carbon monoxide, and hydrocarbons. Roadside air pollution problems have become especially serious. Suspended particulates have become the most serious air pollutant in Bangkok; to reduce such emissions, diesel fuel has been reformulated there by halving its sulphur content. Leaded petrol is rapidly being phased out there. 90% of Bangkok's million motorcycles have two-stroke engines, which have especially high hydrocarbon emissions; low-smoke lubricating oil for these vehicles has now become essential. Cars with petrol engines have been identified as the major source engines have been identified as the major source of carbon monoxide emission. Since January 1993, Thailand has required catalytic converters for all new cars, but this measure could be unsuitable, and its effectiveness at reducing carbon monoxide emissions is to be assessed. Buses in Bangkok are major emitters of suspended particulates, and it has been suggested that they should be fuelled by compressed natural gas, not diesel oil. Three mass transit systems are being implemented to reduce Bangkok's air pollution and traffic congestion; two of them are privately funded, and the third will be financed by both public and private sectors.
Abstract