การหาสัดส่วนฝุ่นละอองขนาดไม่เกิน 2.5 ไมครอน ในฝุ่นละอองขนาดไม่เกิน 10 ไมครอน ที่เกิดจากแหล่งจราจร ในเขตเทศบาลนครเชียงใหม่

Abstract

This research is undertaken in order to monitor PM10 and PM2.5 emission, to study proportion of PM2.5 in PM10 at ambient air quality monitoring station in Kowitthamrong ChiangMai School, as well as to investigate relation between PM10 and PM2.5 emissions and numbers of vehicles near the station area and meteorological factor and studying about proportion of PM2.5/PM10. The equipment for PM10 sampling is Gravimetric system; called “High Volume”. Meanwhile, the equipment for PM2.5 sampling is Federal Reference Method (FRM); called “Low Volume”. The data was monitored and collected during November 2013 to August 2014. This was 24 hours collecting in every 3 days. There are 64 days of complete data. The study results indicate that PM10 concentrations exceed the Thailand National Ambient Air Quality Standards (NAAQS) in 5 days around 120.2 - 156.2 micrograms/m3.There are 2 days that PM2.5 concentrations exceed the NAAQS which are 54.4 and 58 micrograms/m3. This PM concentrations exceed is affected by open burning. Proportion of PM2.5 in PM10 at the monitoring station is around 0.4 ±0.2. PM2.5 and PM10 concentration has inverse relation with temperature and relative humidity. The PM10 correlation coefficients (r) are -0.28 (p<0.05) and -0.63 (p<0.01), respectively. And the PM2.5 correlation coefficients (r) are -0.42 (p<0.01) and -0.24 (p<0.05), respectively. In addition, PM2.5/PM10 proportion has inverse relation with relative humidity. The correlation coefficients (r) are -0.45 (p<0.01). The study result illustrates that, mostly, passenger car has positive relation with PM10 and PM2.5 concentrations. The correlation coefficients (r) are 0.38 (p<0.05) and 0.41(p<0.01), respectively. The research found that proportion of PM2.5 and PM10 not has relation with every kind of vehicle. Consequently, increasing or decreasing a number of vehicles is not related to proportion of PM2.5 and PM10. - In order to forecast PM10 concentration, there are 1 equations that can be used, after preliminary testing and verification, which are YPM10 = 603.26 – 9.75(Temp) - 2.02(RH) (for raining day) - In order to forecast PM2.5 concentration, there are 2 equations that can be used, after preliminary testing and verification, which are YPM2.5 = -66.85 + 0.03(C) + 0.03(P) - 0.07(R) – 0.54(Rain) – 3.03(Temp) YPM2.5 = 45.38 + 0.01(C) - 0.82(Temp) - 0.46(RH) (for non-raining day)