Inventory of kiln stacks emissions and health risk assessment: Case of a cement industry in Southwest Nigeria

Cement production is a significant source of air pollution as both gaseous and particulate materials released are detrimental to the ecosystem. This work was carried out in a cement industry located in Southwest Nigeria. The emission rates of carbon monoxide (CO), nitrogen oxides (NOx), carbon dioxide (CO2) and sulphur oxides (SOx) released from the cement kilns using fuel oil, natural gas (NG) and coal were garnered for a year. Thereafter, the estimated emission quantities of the pollutants were employed to obtain the emission inventory of the cement plant. Uncertainty analysis associated with the emissions was evaluated using Analytica® (4.6). Total amounts of pollutants emitted from the plant were 4.86 tonne (t) (NOx), 18.2 t (SOx), 2.270 Kt (CO2) and 1.17 t (CO). Uncertainty range of –149.38% to 149.38% was connected to all the pollutants. Results showed that the quantities of pollutants discharged from the cement industry were considerably higher than recommended. The evaluated air quality indices for CO, NOx, and SOx implied that the health risk on exposure to these gases was hazardous. This study revealed that NG and wastes are the best fuel for kiln firing to reduce the amounts of pollutants emitted into the microenvironment of the plant.