The study was conducted to observe the effects of seasonal variations (dry and wet) of air pollutant concentration in Narayanganj during November 2016 to October 2017. The highest particulate matter (PM2.5 and PM10) was found in January (237.04 and 397.56 µg/m3) and lowest particulate matter (PM2.5 and PM10) was found in July (20.9 and 39.3 µg/m3). Similarly, the maximum SO2 and NO2 concentration reached (22.5 and 108 ppb, respectively) in dry season (November to March) compared to wet season (1.06 and 25.5 ppb). The study reveals the strong seasonal variations of atmospheric ozone concentrations with dry season maximum (11.28 ppb) and wet season minimum (1.89 ppb) levels. The concentration of all air pollutants showed several times higher level in dry season than those of the wet season (April to October). The study determined the highest AQI value found 821 in January and lowest value found 13 in August.

Key words: Air pollutants, dry season, wet season, AQI, Bangladesh.