THE EFFECT OF SEASONAL VARIATION AND METEOROLOGICAL DATA ON PM10 CONCENTRATIONS IN NORTHERN THAILAND

This study examines emission sources and meteorological data affecting ambient concentrations of pollution haze in Northern Thailand on the basis of particulate matter (PM10) concentrations monitored and collected by Thailand's Pollution Control Department over a three-year period at thirteen stations in eight provinces. Increasing pollution and its major emission sources have been analyzed to reflect the seasonal variation of meteorological data over the periods of dry and rainy seasons. The results show that daily PM10 concentrations were at their highest levels during the dry season from January to April. In the course of a three-year time span, from 2015 to 2017, almost all monitoring stations recorded average PM10 concentration levels that were approximately 1 to 3 times higher than the Thailand's daily ambient air quality standard (120 mu g/m(3)). It was also observed that the average PM10 concentrations in areas under study were significantly higher than the average air quality recorded during the rainy season. The meteorological data, including temperature and winds blowing from the southerly and southeasterly directions, were significantly related to the increase of average PM10 concentrations. By contrast, the relative humidity and the wind speed were significantly related with the decrease of average PM10 concentrations. Forest fires and agricultural waste burning have been identified as the major sources of PM10 concentration in each site.