Background and Aims: Atmospheric dust, also known as a part of PM10, can cause some adverse effects on public health. The aim of this study was to investigate dust concentration trends in Kermanshah city and also to compare related Air Quality Index (AQI) in different years, seasons and months during 2005 to 2012.Materials and Methods: In this descriptive-analytical study, totally 2589 samples were taken from air monitoring stations owned by the Environmental Protection Agency. The ghatered data were then analyzed using SPSS software V.16.Results: The frequency percentage of PM10 concentrations based on AQI descriptions (healthy, moderate, unhealthy for sensitive groups, unhealthy, very unhealthy and dangerous) were 12.16, 68.36, 12.82, 3.43, 0.77 and 2.43 percents, respectively. It is further interesting to note that in all monitored days during the present study, 19.43% of total days were in unhealthy conditions within AQI> 100. So that, although the frequency of dusty days decreased from summer to fall, failure to meet air quality standard requirements increased from fall to winter and further to spring.Conclusion: The results of this study showed that the observed changes in PM10 concentration were significant in the course of seasons and months. The worst air quality condition occured in summer (specially July). It seems possible that these results are due to frequent dust enterance originating from neighboring countries, humidity reduction, drought and unsustainable use of water resources, temperature rising, as well as wind speed and direction. Because of adverse health effects of particulate matter, it is necessary to promote environmentally aware and responsible science of its trend, short-term and long-term and also international planning to reduce its detrimental impacts.Key words: Air pollution, AQI, Dust, Kermansha
