Abstract Air pollution is an important issue around the world. Evidence of air pollution and its impact has been well established by the scientific communities. The effects of these changes on the smaller towns in Brahmaputra valley of Assam still need to be investigated. This study concludes that Suspended Particulate Matter (SPM) and Respirable Suspended Particulate Matter (RSPM) shows increasing trend in all the seasons except during the monsoon season but significant during the winter season. The study also reveals that RSPM remained above the standards throughout the decade, unlike SPM, which rose above the standards only during the years 2006, 2008 and 2009. It is also observed that during the rainy seasons Coefficient of Variation (CV) is high in maximum numbers of stations. The study concludes that exponential increase in population; vehicular activities, rainfall and wind direction as well as geographical conditions have indirectly influenced the pollutions.