Extent of air pollution in Kandy area, Sri Lanka: Morphological, mineralogical and chemical characterization of dust

Abstract

Dust is one of the most common sources of air pollution in cities, providing a considerable health risk. Kandy, Sri Lanka, has been declared as a UNESCO World Heritage Site. As a result, a study into causes of air pollution in Kandy and its environs is urgently required. We examined the composition of dust particles collected from the city and suburbs to determine the degree of particulate pollution. The abundance of particles and materials in various phases has previously been quantified in one dimension in an idealized sphere. The morphological examination of particulate matter is usually ignored. Eighteen road and thirteen household dust samples collected in the Kandy Municipal area were analyzed for elemental concentrations, as well as for mineralogical and morphological characteristics. Higher Ca, Zn, and Cu concentrations in the samples indicate anthropogenic (construction industry and traffic activities) influences on the dust. Mineralogically, fine and coarse dust fractions are dominated by clay minerals and quartz with feldspar. The majority of fibrous materials in dust are coated with secondary matter, resulting in short suspension duration in the atmosphere and, as a result, a reduction in the harmfulness of the fibers. In terms of mineralogy, morphology, and chemical properties, road and household dust samples are nearly identical. Despite the fact that dust is primarily derived from soil, its composition has been altered due to anthropogenic influences such as transportation and construction activities. As a result, dust containing clay particles can be regarded of as a fluxing and heavy metal accumulation medium. Although fibers have minor influence on human health and the environment, heavy metals have a significant impact. Though industrial and transportation activities in Kandy are remarkably low when compared to those in other major cities in Sri Lanka and megacities around the world, pollution levels in the city are comparably high. To reduce the vulnerability of the current pollution condition of the city, appropriate, long-term strategies for construction and transportation activities are required.