Diurnal variation of Ground Level Ozone and Nitrogen Dioxide concentration during festive and non-festive holidays in Kelantan

Ground level ozone (O3) is produced from primary pollutants (NOX) and volatile organic compounds (VOCs) which are adversely affect human health and the natural environment. In this study, diurnal variation of O3 and NO; concentrations during festive and non-festive holidays in Kelantan and Terengganu were observed. The continuous air monitoring data (2013-2014) in Kota Bharu and Terengganu were obtained from Air Quality Division, Department of Environment (DoE), Malaysia. The obtained data were divided into festive and non-festive holidays according to specific date of the celebrations and analysed using descriptive statistics, box and whisker plot, time series plot and diurnal plot. The maximum value of ozone concentration was recorded during non-festive holidays in Terengganu 2014 with 90 ppb. The diurnal patterns of ozone for both locations during festive and non-festive holidays were showing a consistent trend with slightly different magnitude. The magnitude of diurnal pattern for ozone and nitrogen dioxide concentration during non-festive holidays was higher than festive holidays. The minimum ozone level was observed at nighttime (started from 6 p.m. to 10 p.m.) and before sunrise, meanwhile the maximum level of ozone concentration was at noontime (started from l2 p.m. to 2 p.m.). The diumal pattems for nitrogen dioxide concentrations were showing the dwi-modal peaks, where at the morning (6 a.m to 10 a.m) and evening rush hour (started from 6 p.m. to 10 p.m.) The comparisons of diumal variation of these pollutants during festive and non-festive holidays were analysed using independent sample T-Test. The results showed that commonly there were no significant differences between non-festive and festive holidays in Kelantan and Terengganu except for Kuala Terengganu in 2014. The results showed that O3 concentration for non-festive holidays is higher in Kelantan and Terengganu. O3 and NO; concentration showed the significant diurnal trend in Kelantan and Terengganu for both years following their typical trends