Trends of Transformation Characteristics of Ground-Level Ozone in Urban Peninsular Malaysia

Abstract

Ozone (O3 ) is the second prominent air pollution in Malaysia. The annual variation of ozone concentration depends upon several conditions such as the sources of its precursor, the land use type and meteorological parameter. This study aims to understand the trends and issues of transformation characteristics of O3 in 4 urban area (Shah Alam, Kajang, Johor Bahru and Kota Bharu) during specific critical conversion time (CCT) as well as to introduce the critical transformation time (CTT) of O3 in 4 selected continuous air quality monitoring stations (CAQMS) from the year 2000 to 2011. The identification of CTT for O3 formation was identified occurring between 8.00 a.m and 11.00 a.m., and the O3 uni-modal peaks usually after CTT at approximately between 12.00 p.m and 4.00 p.m. The results indicated that the CTT of O3 in the Kota Bharu is slightly earlier occurring between 8.00 a.m to 10.00 a.m whereas Shah Alam, Kajang and Johor Bahru the CTT later occurring between 10.00 a.m to 11.00 a.m. Only Kota Bharu recorded data was below 100 part per billion volume (ppbv), while Shah Alam, Kajang and Johor have recorded exceedances above 100 ppbv. This research elucidates that CTT is adequate to control ozone concentration. Ozone might exceed Recommended Ambient Air Quality Guideline (RMAAQC) unless nitrogen emissions are adequately managed, due to the detrimental effects for those who are at risk of respiratory health problems resulting from air pollution.