Seasonal and long term variations of surface ozone concentrations in Malaysian Borneo

Abstract

Malaysian Borneo has a lower population density and is an area known for its lush rainforests. However, changes in pollutant profiles are expected due to increasing urbanisation and commercial-industrial activities. This study aims to determine the variation of surface O3 concentration recorded at seven selected stations inMalaysian Borneo. Hourly surface data covering the period 2002 to 2013, obtained fromtheMalaysian Department of Environment (DOE),were analysed using statisticalmethods. The results showthat the concentrations ofO3 recorded in Malaysian Borneo during the study period were below the maximum Malaysian Air Quality Standard of 100 ppbv. The hourly average and maximum O3 concentrations of 31 and 92 ppbv reported at Bintulu (S3) respectivelywere the highes tamong the concentrations recorded at the sampling stations. Further investigation on precursors showthat sampling sites located near to local petrochemical industrial activities, such as Bintulu (S3) andMiri (S4), have higher NO2/NO ratios (between 3.21 and 5.67) compared to other stations. The normalisedO3 values recorded at all stationswere higher during theweekend compared toweekdays (unlike its precursors) which suggests the influence of O3 titration by NO during weekdays