Air pollution levels in selected sites in Malta & Gozo

Abstract

It was generally assumed that on a small and windswept island such as Malta air pollution would not present any particular problems. Such a misconception was probably the main reason why the topic had never been given the deserved attention. Several socio-economic changes compounded by an augmentation in terms of the public awareness with respect to environmental and health issues paved the way to research being instituted in this regard. Information regarding the ambient air quality of the Maltese Islands had been sparse. A preliminary assessment could therefore shed light with respect to the temporal and spatial variation of the air pollutants that are most likely to be of concern. The main objective of this study was precisely to give a preliminary yet thorough evaluation of the situation. For this purpose sixteen representative sites were selected each having distinct geographical, topographical and sociological characteristics. The levels of air pollutants namely carbon monoxide, oxides of nitrogen, ozone , particulate matter and sulphur dioxide were continuously assessed using modern and state of the art analysers. Some areas, being representative of the north, central and southern sectors of the island, were monitored during different phases of the year in order to tentatively try to detect some trends. The main results obtained from this study led to several important conclusions. The levels of sulphur dioxide were significantly higher to the southern parts of the island. On the other hand the levels of ozone and nitric oxide were significantly higher to the northern region. Levels of nitrogen oxides (NOx) were high both at the northern and southern regions. The levels of carbon monoxide were surprisingly low whilst the levels of particulate matter ( PM10) were particularly high at all the monitored sites. Since the levels of air pollution at any locality are primarily determined by the magnitude and the distribution of the emission sources, on the local topography and local meteorology, attempts were made in order to try to determine the source and the cause for the prevalence of these pollutants. The slightly higher levels of sulphur dioxide and nitrogen oxides found to the south of Malta could be attributed to fossil fuel combustion at the power plants. The levels of carbon monoxide and nitrogen oxides recorded at all the sites could invariably correlated to vehicular and other mobile sources. Whereas the higher levels of ozone to the north could be the result of trans-boundary transport from other parts of the Mediterranean. The insignificance with respect to the spatial and temporal prevalence of the particulate matter fraction denotes that several sources could be at play. In education and research, future work should be dedicated to measuring the effects that the current levels of air pollution may have on the health of the general population as well as the adverse impacts that certain air pollutants may have on our natural and cultural heritage.