Comparative Assessment of Indoor Air Quality in Residential Environments of Urban Centre and Petroleum–Producing Communities in Akwa Ibom State, Nigeria

Indoor air quality (IAQ) is a growing public health concern, particularly in regions experiencing rapid urbanization and intensive petroleum-related industrial activities. This study conducted a comparative assessment of IAQ in residential environments across Uyo (urban centre) and two petroleum-producing industrial communities, Ibeno and Eastern Obolo, in Akwa Ibom State, Nigeria. Measurements were conducted during both dry and rainy seasons, covering particulate matter (PM₁, PM₂, PM₅, PM₁₀), carbon monoxide (CO), carbon dioxide (CO₂), nitrogen oxides (NO and NO₂), ozone (O₃), relative humidity (RH), and temperature (TEMP) using Portable Air Quality Monitors (Fluke 985 Particle Counter, Fluke 975 AirMeter, and Aeroqual Series 500 Monitor). Descriptive statistics, correlation analysis, and principal component analysis (PCA) were employed to characterize pollutant patterns and potential sources, while mixed-effects models and time-series analysis were applied to evaluate spatial–temporal variations and seasonal cycles. Results indicated significantly higher concentrations of particulate matter and CO in industrial zones compared to the urban environment, especially during the dry season. While CO₂ levels were relatively consistent across sites, NOx concentrations were markedly elevated in industrial zones. Seasonal variations highlighted that pollutant levels peaked in the dry season, correlating with reduced natural ventilation and dust resuspension. PCA highlighted strong co-loading of PM species in the industrial communities, suggesting dominant contributions from petroleum-related activities and industrial emissions. Mixed-effects modeling confirmed season and location type as significant predictors of pollutant levels (p < 0.05), while time-series decomposition showed systematic reductions in pollutant concentrations during the rainy season, attributable to atmospheric washout and improved ventilation. The findings underscore the disproportionate indoor exposure risks faced by residents in petroleum-producing communities, with implications for respiratory and cardiovascular health. This study highlights the need for targeted IAQ management strategies, including improved household ventilation and regulatory oversight of industrial emissions, to protect vulnerable populations in the Niger Delta region.