The increasing concentrations of air pollutants are now a global challenge. This research aimed to assess the meteorological parameters and atmospheric pollution in urban and rural areas of River State in Nigeria using Air Quality Index (AQI) ratings. The atmospheric quality status of the survey areas was analysed during the rainy season from April to July, 2018. In this study, Nwaja, Trans Amadi Industrial Layout, Port Harcourt Local Government Area (urban) and Umuazu village, Igbo-Etche, Etche Local Government Area (rural) in Rivers State, Nigeria gave recorded mean values for particulate matter as follows; PM2.5 ranging from 107.30-113.00 μg/m3 and PM10 (145.30-153.00 μg/m3) in both areas. Other parameters analysed showed relative humidity (84.67-95.00 %), wind speed (0.97-2.97 m/s), elevation (40.33-108.30 m), cloud cover (98.33-99.33 %) and temperature (24.30-26.00 oC). Other results (ppm) were; CO2 (8600.00-17500.00), Cl2 (1.85-2.39), CO (29.67-44.30), SO2 (0.60-0.75) and NO2 (0.33-0.43) in both locations. From the obtained results, the study areas showed high concentrations of air pollutants which might be toxic to humans as well as plants and animals in the environment. The Air Quality Index (AQI) ratings of the obtained results showed that the area with high industrial activities (urban) was rated from Very Poor (E) to Hazardous (F) while in the area with less industrial activities (rural), it was rated from Moderate (C) to hazardous (F). Hence, there is a need for routine monitoring of the atmospheric pollutants in Rivers State and in South-South Nigeria as a whole to ensure safety.