The contamination of air environment by industrial activities is a global problem mostly in the underdeveloped and developing Nations where environmental issues are handled with levity. This research investigated the impact of industrial activities on air environment at the following companies; Crude Oil processing (COPC), beer processing (BPC), asphalt processing (APC), metal processing (MPC), and construction Company machinery Yard (CCMY) in Southern Nigeria. Air Monitors were employed to quantify nitrogen (IV) oxide (NO2), sulphur (IV) oxide (SO2), hydrogen sulphide (H2S), cabon (II) Oxide CO, total volatile organic carbon (TVOC), and suspended particulate matter (SPM) at the studied locations. The mean values of NO2, SO2, H2S, and CO obtained at all the industrial locations were higher than their recommended limits by the Federal Environmental and protection Agency (FEPA) except at BPC. The mean levels of TVOC were higher than the limit at all the locations apart from BPC and CCMY. However, the mean levels of SPM at all locations were higher than the permissible limit. The general trend for the discharge of air pollutants indicated that, COPC and BPC were rated the highest and lowest, respectively. The air quality index (AQI) values obtained revealed that, all the air pollutants at all the locations except BPC were harmful to human health. Nevertheless, the mean AQI value of SPM at BPC was also in the hazardous class. The Principal component analysis (PCA) confirmed that, industrial activities at the studied locations were responsible for the accumulation of these toxic substances in the adjoining air environment. Hierarchical cluster analysis (HCA) for the air pollutants corroborated that most of the parameters were from a common source. HCA for the studied locations indicated similarities between BPC and CCMY, APC and MPC, while COPC was in a separate cluster. Thus, this study has shown the effects of untreated gases released from industries into the air on the environment and appropriate measures should be adopted to ameliorate the trend.