Variation of Ground-level Ozone in the West Coast ofPeninsular Malaysia

摘要

Hourly air pollutants data and weather parameters over the time period of 2008-2012 wereobtained from the Air Quality Division, Department of Environment (DOE) Malaysia. Themain aim of this study is to examine the variations of ground-level ozone in the west coast ofPeninsular Malaysia. Shah Alam recorded the highest number of hours and days of ozoneconcentration above the threshold limit that was suggested by the Recommended Malaysian AirQuality Guidelines (RMAQG) with a maximum concentration of 0.158 ppm. The highest ozoneconcentration recorded in Petaling Jaya and Nilai were 0.12 ppm and 0.115 ppm respectively. Thediurnal pattern shows that the maximum concentration was observed in the afternoon, whichis the peak occurred between 2 p.m. to 4 p.m. and a minimum reading was recorded early inthe morning and night-time. Analysis of ozone concentration and its precursors showed thatthe amount of Ultraviolet B (UVB) and the concentration of nitrogen dioxide had impacted theozone photochemistry through the titration processes. The results show that there are visibleseasonal patterns in the ground-level ozone among the three stations. The high concentrationof ozone is usually observed between January to April (end of northeast monsoon that bringhot temperature from Cambodia) whereas the wind direction during different monsoons wasfound out to influence the concentration of surface ozone.