Nowadays devastating consequences of indoor air pollution is more than outdoor air pollution. The particulate matter pollutant emitted from natural and anthropogenic sources such as dust storm and office equipment reduces indoor air quality dramatically. Due to the detrimental effects of particulate matter on health, the present study aims to explore the indoor air quality using Lighthouse HANDHELD 3016 Particle Counter in residential and office buildings in Kermanshah city. The results of the research indicated that water air conditioners have brought much more particulate matters into the indoor environments rather than gaseous air conditioners. Also, the measurements in the printing office with the most number of photocopiers and printers in Kermanshah city have shown a significant increase in the concentration of fine particles during the printing process in comparison to off mode.