Annual concentration report and emission sources analysis of the air pollutants measured by the air quality monitoring station

Abstract

Problem statement: Air Quality Monitoring (AQM) station at Kasetsart University, Si Racha Campus, Thailand, wasroutinely monitor the annual concentrations and analysis the emission sources of the air pollutants in the areasince 2007. The level of concentration CO, SO 2, NO x and O 3 were measured. PM 10 concentration was measured by mean of TOEM method. The PM 10 and TSP (manifold) filters were collected for the measurement of heavymetals adsorbed in the particulate by ICP-AES techniques. Scanning Electron Microscopic (SEM) and EnergyDispersive Spectrometric (EDS) techniques were used to identify the morphologies and elemental compositionsof particulate matters from the PM 10 and TSP filters. Approach: The annual concentrations of all pollutants were almostreal-time reported from July 2007-2008. The O 3 concentrations are higher than the standard level (100 ppb) in July 2007 and April 2008 with the value of 109 and 114 ppb, respectively. Average PM 10 concentrations arehigher than the standard level (120 μg.m -3) in November 2007, January 2008 and March 2008 with the value of129, 123 and 125 μg.m -3, respectively. Strong correlations between NO 2 with O 3 and between NO 2 with PM 10were found. Results: These results show that NO 2 is the precursor of the photochemical reaction and generate O 3. NO 2concentrations are found to be corresponding with both O 3 and PM 10. The directions of O 3 emission sources arethe southwest, south and southeast due to wind direction, whereas the PM 10 are originated from the northwest.The microscopic structures of TSP provided various shapes and dimensions from 0.1 to greater than 100 μm, while the microstructures of PM 10 presented the needle-like and spherical shape. SEMEDS analysis was able todetect some element (C, O, F, Na, Al, Si and K), while the ICP-AES showed that there were other heavy metalspresent in the filter sample (Ni, Cu, Zn, Pb and Se). Conclusion: Among the amounts of selected heavy metals, Zn was the most probable among all metals with the value of 1.3891±1.6198 μg.g -1.m -3 in TSP. Amounts of heavy metals inPM 10, Cu was dominated with 0.5374±0.8084 μg.g -1.m -3, the others were almost in the same levels and muchlower than in TSP. Correlation coefficient between each metal can be estimate the emission source of theirparticulate matter together with the wind speed and wind direction. © 2011 Science Publications.