Assessment of Air Quality Around Cement Production Facilities in Obajana, Kogi State

This study assesses ambient air quality in communities surrounding the Dangote Cement plant at Obajana in Kogi State, North Central Nigeria, one of the largest cement production facilities in sub-Saharan Africa. Cement manufacturing involves extensive quarrying, kiln combustion, and clinker processing operations that generate particulate matter, nitrogen oxides, sulphur dioxide, and carbon monoxide, which can adversely affect the respiratory health of adjacent communities. Air quality measurements were conducted at twelve monitoring stations placed at varying distances from the plant boundary in the prevailing and cross-wind directions. Particulate matter concentrations were measured as PM10 and PM2.5 using gravimetric methods, while gaseous pollutants were measured using calibrated electrochemical sensors. Measurements were taken over twelve weeks covering both production and planned maintenance shutdown periods. Results indicate that PM10 concentrations at the nearest residential receptor locations exceed the Nigerian Ambient Air Quality Standards during active production, with the highest exceedances recorded in the north-easterly wind direction. PM2.5 levels at three monitoring points exceed the WHO guideline value of 15 micrograms per cubic metre as an annual average. Nitrogen oxide concentrations are within acceptable limits at all stations. Community surveys indicate a high prevalence of respiratory symptoms including persistent cough and shortness of breath in communities within one kilometre of the plant. The study recommends upgrading the plant's bag filter and electrostatic precipitator systems, establishing a real-time air quality monitoring network, and implementing dust suppression on haul roads. Keywords: air quality, cement plant, particulate matter, Obajana, respiratory health.