An analysis of deposited dust from indoor microenvironments across Malta using SEM, EDX and XRD

Abstract

People spend over 70% of the time indoors. As indoor air quality is becoming important, the main aim of this study was to analyse indoor deposited dust from Maltese homes. The methods used to analyse these samples were scanning electron microscopy (SEM) Energy Dispersive X-ray Spectroscopy (EDX) and X-ray Diffraction (XRD). SEM produces detailed images of the sample whilst EDX gives a semi quantitative analysis of the elements present at the surface of the sample and XRD gives a detailed crystallographic analysis of the type of crystals present in the dust. Initially, different locations were chosen to identify if they were indicative of different elements in the chosen samples. Other samples from specific sources were chosen according to literature and analysed to characterise the possible components that could be found in indoor deposited dust. The Island of Malta was split into four areas according to the location's surroundings, identified as Agricultural, Quarries, Urban and Industrial. A total of 20 deposited dust samples were collected from each area. Notably, the main two crystals found in all the analysed samples were Calcite (CaCO3) and Quartz (SiO2), which resulted in no major differences between areas. Furthermore, this shows that in Malta, the main source of our indoor deposited dust is mainly coming from limestone.