Analysis of Seasonal Variation in Air Quality Around Obajana Cement Plant, Kogi State

Industrial cement production is one of the most significant stationary sources of particulate matter and gaseous pollutant emissions in Nigeria, generating localised air quality degradation that affects surrounding communities and agricultural lands. This study analyses seasonal variation in air quality in communities surrounding the Obajana Cement Plant in Kogi State, one of Africa's largest cement manufacturing facilities. Ambient air quality monitoring for PM10, PM2.5, sulphur dioxide, and nitrogen dioxide was conducted at twelve community sites at distances ranging from one to eight kilometres from the plant boundary during both wet and dry seasons over a 12-month monitoring period. Wind direction data were incorporated to assess directional pollutant concentration patterns. Agricultural productivity surveys were administered to 90 farming households to assess perceived impacts of dust deposition on crop yields and quality. Results reveal PM10 exceedances at 75 percent of monitoring sites during dry season months, with levels two to three times higher than during the wet season due to reduced atmospheric deposition and prevailing harmattan wind patterns. Communities located north-east of the plant along prevailing wind directions experience significantly higher dust deposition levels. Farmers within three kilometres of the plant report 20 to 35 percent yield losses attributed to dust coating of leaf surfaces impeding photosynthesis. The study recommends enhanced wet suppression and enclosure of conveying systems, installation of a plant-perimeter air quality monitoring network, and compensation protocols for demonstrable crop yield impacts. Keywords: cement plant emissions, air quality, particulate matter, Obajana, industrial pollution.