Measurement of Atmospheric Particulate Matter Concentrations Around Cement Manufacturing Facilities in Cross River State

Cement manufacturing generates substantial atmospheric particulate emissions that pose documented risks to respiratory health and local environmental quality. This study measures PM2.5 and PM10 concentrations in communities surrounding the Calabar Cement Plant and a second facility in Cross River State, South South Nigeria. A calibrated optical particle counter and gravimetric filter-based samplers were deployed at six monitoring stations at varying distances from each facility over a three-month sampling period. Meteorological parameters including wind speed, wind direction, and relative humidity were concurrently recorded to support dispersion analysis. Measured PM2.5 concentrations at the nearest residential monitoring station exceeded the WHO 24-hour guideline of 15 micrograms per cubic meter on 68 percent of sampling days during dry season operations. The study applies a Gaussian dispersion model to estimate facility contribution to observed concentrations and identifies seasonal wind patterns that channel emissions toward densely populated residential areas. Comparison of upwind and downwind stations confirms that facility emissions are the dominant source of elevated particulate loading in affected communities. The research maps health risk zones based on cumulative particulate exposure estimates and identifies vulnerable populations including children and elderly residents in adjacent settlements. Recommendations address operational dust suppression measures, buffer zone enforcement, and community health monitoring programs. Keywords: particulate matter, PM2.5, cement manufacturing, Cross River State, air quality