Investigation of PM 2.5 Concentration in the Wet Season of Bangkok, Thailand

Abstract

<p>Background: Particulate Matter 2.5 (PM2.5) has been attributed to more health consequences compared to the prevalent concentrations of Particulate Matter 10 (PM10). Bangkok is known to have a high level of PM2.5 during dry seasonal haze episodes. Its prevalence had been further observed along PM10 and a smaller particulate matter, particulate matter 1 (PM1). Studies regarding the prevalence of PM2.5 during non-haze episodes are not available. The extent of various chemical molecules such as Nitrogen Dioxide (NO2) and Volatile Organic Compound (VOC) as the triggering factor of PM2.5 are also unknown.<p/>

<p>Objective: To identify the PM concentrations and prevalence in the environment and to determine the chemical molecules concentration as the triggering factor of PM2.5 in Bangkok, Thailand during dry seasonal non-haze episodes.<p/>

<p>Methods and Materials: PM2.5, PM10, and PM1 concentrations were measured using AirBeam 2 and Aslung. Additionally, NO2, VOC, and PM2.5 concentrations were measured using Plume. Samples were collected in Bangkok during wet season from different locations and using various modes of transportation. AirBeam 2 and Aslung measured PM by direction, and modes of transportation were analyzed via descriptive statistics and illustrated with a bar graph to compare PM concentrations. Plume measurements were analyzed using linear correlation to determine the significance of NO2 and VOC to PM2.5.<p/>

<p>Results: Overall, NO2 and VOC were significant to the formation of PM2.5 with the correlation of 0.255 and 0.114 respectively (n=882). In the moving ferry-boat (Khlong Sansaep), surrounded by water, there is a higher prevalence of PM2.5. However, PM10 is still more prevalent in the moving ferry-boat (Khlong Sansaep) compared to PM2.5 and PM1.; average= 52 μ/m3 and 20 μ/m3, respectively.<p/>

<p>Conclusions: NO2 and VOC trigger the high concentration of PM2.5 in ferry-boat located in the west (Khlong Sansaep). We found lesser prevalence of PM2.5 than PM10 throughout Bangkok. Determining areas with the highest concentration of PM2.5 allows for monitoring increases in air pollution and ways to mitigate the occurrence of haze episodes. These data can be used as the baseline information for the comparison of haze episodes during dry season.<p/>