This study investigated the relationship between exhaust emission from moto
rcycles and ambient air quality in Bangkok Metropolitan Region (BMR). The t
est result revealed that average pollutant concentrations of the test motor
cycles in terms of hydrocarbon, carbon monoxide and nitrogen dioxide were 8
.38, 16.69 and 0.04 g km(-1), respectively. The finding also indicated that
two-stroke motorcycles emitted 1.5 and 5 times more carbon monoxide and hy
drocarbon emission, respectively per kilometer driven than do four-stroke m
otorcycles. Four air sampling stations were strategically established to ev
aluate the air pollution problems in Bangkok arising from vehicle exhaust e
mission. Investigation was carried out to determine the correlation between
average air pollutant concentration with different traffic configuration i
n each traffic zone of Bangkok Metropolitan Region (BMA) during peak/non pe
ak hours, day/night times and weekday/weekend. The average concentrations o
f PM(1)0 particulate matter, carbon monoxide, nitrogen dioxide and sulphur
dioxide in Bangkok street air were found to be 84.33 mug m(-3) (24 hr ave.)
, 7.05 mg m(-3) (8 hr ave.), 56.74 mug m(-3) (1 hr ave.) and 9.60 mug m(-3)
(24 hr ave.), respectively.