Abstract:
To identify the contribution of polycyclic aromatic hydrocarbons (PAHs) in particulate matter in Bangkok ambient air by nano-particle sampler, which can collect size-selected particulate matter, namely less than 0.1 um (less than 100 nm or nanoparticles) , 0.1-1 mum, 1-2.5 um, 2.5-10 mum and >10 um. The sampler cutoff flow rate was 40 l/m. The samplings were carried out every 6 days for 2 months at each station for the total period of 6 months during November 2008 until May 2009. The sampling were taken at 3 locations: roadside area at Pollution Control Departments Dindaeng air quality monitoring station (PCD AQ station) and background area at 2 stations; namely Bansomdet Chaopraya Rajabhat University PCD AQ station and Chulalongkorn University. The results at Bangkok roadside area showed the proportions of PM10-2.5, PM2.5-1.0, PM1.0-0.1 and PM0.1 to the total PM10 mass averaged for 3 stations were 33.35, 22.62, 33.31 และ 10.72 percent. The average PM2.5/PM10 ratios of roadside area to background area were 0.67 and 0.66. The PAHs concentration result showed dominant PAHs in every particulate matter size is Benzo(a)pyrene Benzo(b) fluoranthene Acenaphthylene and Fluorene. CMB showed major sources of PAHs is traffic which came from four stroke motorcycle, tuktuk, compressed natural gas vehicles and two stroke motorcycle.