Ozone Trends from Two Decades of Ground Level Observation in Malaysia

Fatimah Ahamad,Mohd Talib Latif,Chung Jing Xiang,Liew Juneng,Paul T. Griffiths

doi:10.3390/atmos11070755

Abstract

We examine the change in surface ozone and its precursor behavior over 20 years at four locations in western Peninsular Malaysia which have undergone urban-commercial development. Trend and correlation analyses were carried out on ozone and oxides of nitrogen observation data over the periods of 1997–2016 as well as the decadal intervals of 1997–2006 and 2007–2016. Diurnal variation composites for decadal intervals were also plotted. Significant increasing ozone concentrations were observed at all locations for the 20-year period, with a range between 0.09 and 0.21 ppb yr−1. The most urbanized location (S3) showed the highest ozone trend. Decadal intervals show that not all stations record significant increasing trends of ozone, with S1 recording decreasing ozone at a rate of −0.44 ppb yr−1 during the latter decade. Correlation analysis showed that only oxides of nitrogen ratios (NO/NO2) had significant inverse relationships with ozone at all stations corresponding to control of ozone by photostationary state reactions. The diurnal composites show that decadal difference in NO/NO2 is mostly influenced by change in nitric oxide concentrations.

Highlights

Surface ozone (O3 ) is a pollutant that affects human health and crop yields [1,2,3,4]
The main aim of this study is to identify O3 and oxides of nitrogen trends over two decades at four locations in western Peninsular Malaysia that have undergone urban-commercial development
The trends in deseasonalized Monthly mean (Mmean) O3 show that there has been an increase in O3 within the

Summary

Introduction

Surface ozone (O3 ) is a pollutant that affects human health and crop yields [1,2,3,4]. O3 studies in urban areas, in the urban-commercial hub within and around Kuala Lumpur, the capital city of Malaysia, have shown frequent incidences of high O3 and other pollutant concentrations such as particulate matter [5,6,7]. Within the greater Klang Valley conurbation, which is the most densely populated area in Malaysia, surface O3 exposure has reached levels that pose significant risks to health [4]. Concerns on air quality discussed in popular media in Malaysia are typically associated with severe haze episodes caused by large scale biomass burning in the region that causes perceivable reduction in visibility [8,9]. Since O3 is a colorless gas that does not have a pungent odor, there is likely less awareness of the severity of O3 pollution when it is not accompanied by haze episodes

Objectives

Results

Conclusion