DETERMINING CURRENT SITUATION OF FINE PARTICULATE MATTER IN CHACHOENGSAO PROVINCE

This research principally pays attention on determining the current situation of fine particulate matter known as PM2.5 in Chachoengsao Province, situated in the east of Thailand, to check if the process change is encountering set the daily Thailand’s national air quality standard. The aim will be succeeded by investigating the important characteristics of PM2.5 concentrations for a year (from November, 2020 to October, 2021) with descriptive statistic and cluster analysis. The process means of PM2.5 concentrations for 5 months (from November, 2021 to March, 2022) are later examined with the exponentially weighted moving average chart called EWMA chart. The results of cluster analysis expose that PM2.5 concentrations are affected by not only a season but also a time period during a day. The concentration of PM2.5 is highest in Winter particularly a day time but lowest in Rainy season specifically a night time. The EWMA chart taken by only one air quality monitoring station; Tungsadao Subdistrict Municipality, Wang YenSubdistrict, Plaeng Yao District, in Chachoengsao Province is acutely able to monitor changing in the level of daily maximum of PM2.5 concentrations. It can also point out the process means of PM2.5 concentrations are out of control state as indicating of a false alarm in December, January and February. Besides, the EWMA chart can plainly express some more days (53 days) as the warning days to pay attention because all values of those days outweigh Thailand’s standard as such 18 days in January, 19 days in February and 16 days in March.