Assessment of the Environmental Impact of Selected Industrial Gaseous Waste on Outdoor Air in Ilorin Metropolis

Abstract

Industrial air pollution remains a growing environmental and public health concern in many developing urban centres. This study assessed the environmental impact of selected industrial gaseous emissions on outdoor air quality in Ilorin Metropolis, Kwara State, Nigeria. The study evaluated the concentration levels of particulate matter (PM2.5 and PM10), carbon monoxide (CO), volatile organic compounds (VOCs), and formaldehyde (HCHO) within the vicinity of selected industries. A descriptive and longitudinal study design was adopted. Fifteen sampling points were selected around five industries, namely Dangote Group of Companies, Doyin Group of Companies Nigeria Limited, International Tobacco Company, Tuyil Pharmaceutical Company, and Glister Quarry Company. Air quality measurements were conducted using calibrated handheld multi-gas monitors. In addition, 150 questionnaires were administered to residents to assess health impacts and awareness of air pollution regulations. Data were analysed using descriptive statistics and a paired-sample t-test at p < 0.05. The findings revealed that PM2.5, PM10, HCHO, and CO concentrations exceeded permissible limits in several locations, indicating poor air quality and potential environmental and health risks. VOC concentrations remained largely within acceptable limits. Significant differences were observed between morning and evening concentrations for HCHO, VOCs, and CO (p < 0.05), while PM2.5 and PM10 showed no significant variation. Frequent cough, wheezing, and nasal congestion were identified as major health complications associated with industrial emissions. Furthermore, 80% of respondents were unaware of legal provisions regulating industrial air pollution. The study concludes that industrial emissions significantly contribute to outdoor air pollution in Ilorin Metropolis and pose considerable health risks to nearby residents. Strengthening environmental regulations, enhancing public awareness, and implementing effective pollution control measures are recommended.