A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development

Thesis (M.Sc.) - Asian Institute of Technology, 1999

Rapid increase of motorcycles, the main private means of transportation in HCMC, is one of major reasons for road congestion and traffic jams. The registered motorcycle number is more than 85% of total vehicle population and it is estimated that about 91 % of travel in the city are by motorcycles. Most motorcycles are four-stroke, which are not equipped with air pollution control devices. In this study motorcycle emission inventories have been made for HCMC to estimate air pollutant loads. The pollutant loads from motorcycle emissions is about 200 tons of TSP; 152,800 tons of CO; 12,600 tons ofHCs; 2,200 tons ofNOx; 3,200 tons of S02 and 40 tons of lead, per year. It has been estimated that the vehicle emissions contribute up to 21 % of CO and 30 % of NOx to the total pollutant loads from the transport and industrial sectors. The assessment of air quality status in HCMC is based on measurement results of existing air quality monitoring networks and Vietnamese environ.mental standards. Although the concentrations of air pollutants now meet the allowable Vietnamese standard for ambient air quality except TSP, they are expected to rapidly increase unless proper measures in environmental management strategies are implemented. Management measures can be incorporated into an integrated air quality and transport management.