Abstract

Particulate matters can be transferred distances from their sources. Due to different chemical and microbial characteristics, they can potentially impact on public health and ecosystems. Therefore, in this study we aimed to study the concentrations of particulate matters (PM2.5 and PM10) and types of bacteria in the ambient air of Ham city during dusty (PM10 >= 150 mu g/m(3)) and non-dusty days from February 2012 to February 2013. Totally, there existed more dust storm events during warm and dry months. The Mann-Whitney test confirmed a significant relationship between dusty and non-dusty days (P < 0.05). Totally, by increasing the PM concentrations, the number of bacterial colonies increased. Kruskal-Wallis test showed that there was a significant relationship between the number of bacterial colonies and season. The mostly observed bacterial colonies were Staphylococcus, Cryptococcus, Corynebacterium, Bacillus, Actinosynnema, Nocardioides, Arthrobacter, Flavimonas, Paenibacillus, Pseudomonas, Microbacterium, Planococcus, Streptomyces, Kurthia, Neisseria Agrococcus, Curtobacterium, Duganella, Ancylobacter, Paracoccus, Propionibactertum, Pseudomonas, Rhizobium and Enterococci. The predominant direction of dust plumes in Ilam city was from the west of Ilam from neighboring countries. The higher number of microbial colonies during dusty days in this city obviously showed the important role of these events on microbial characteristics.