Abstract:
This study is on relationship between particulate matter of less than 10 micron (PM10) and meteorological and traffic factors. The sites chosen for the study were three roads in Bangkok, Thailand, which are Indrapitak Road, Din Daeng Road and Lad Phrao Road. PM10 data (2002-2011) were obtained from Pollution Control Departments monitoring stations, and statistical analysis was performed by Pearsons correlation, linear regression and multiple regression. The results indicates that while PM10 concentration in general is decreasing throughout the years studied, the seasonal pattern is clear that winter months have highest concentrations, followed by summer and rainy seasons months respectively. Among the meteorological parameters, temperature exhibits strongest negative correlation with PM10 concentrations, with r = -0.239 and -0.441 for Indrapitak Road and Lad Phrao Road respectively. It also shows that low wind speeds, low temperature, stable condition and low sunlight radiation promote higher PM10 concentrations. Rain effects on PM10 only during rainy season which may be due to the suppression of fugitive road dust re-entrainment. On the effect of traffic volume on PM10 concentrations it was found that the PM10 was not related to the traffic volume as a whole but was more related to diesel vehicles, particularly buses, but since the study sites are urban with few of the diesel vehicles (buses) the effects are not very clear, and this study recommends that future studies may choose sites with more diesel vehicles, such as suburbs and near major ports. Local factors such as geographical features also influence meteorological at sites and were found to have effects on PM10