Atmospheric dispersion modeling of uncontrolled gaseous pollutants (SO2 and NOX) emission from a scrap-iron recycling factory in Ile-Ife, Southwest Nigeria

In the last decade, government policies promoting foreign investments in the industrial sector particularly for small and medium scale enterprises in Nigeria have led to increased establishment of scrap-iron recycling factories in many states of the federation. Albeit the economic benefits in terms of waste material sourcing and job creation, these scrap-iron recycling factories have attracted significant public criticism due to the characteristic uncontrolled pollution (toxic gases) plume released from their operations into the atmospheric environment of host communities and thus aggravating existing and unresolved rural and urban air pollution problems in Nigeria. This study therefore provides model-based estimates of atmospheric dispersion for gaseous pollutants (SO2 and NOX) released from a scrap-iron recycling factory located in Ile-Ife, southwest Nigeria as a case study for investigating emission signature from such sources. Meteorological parameters measured at the factory location in 2012 and 2013 were used to execute U.S recommended short range (<50 km) Gaussian-based regulatory air pollution dispersion model (AERMOD: American Meteorological Society/Environmental Protection Agency Regulatory Model, v12060). Isopleths of maximum concentration values for 1 h averaging period were projected to occur within 1.5 km radius from the factory in SW and NW directions during early morning hours (02:00-06:00 h (GMT + 1)). Prevailing meteorological conditions during periods of maximum concentration were characterized by stable atmosphere dT/dz (>0.01 degrees C/m), very weak winds (<1.5 ms(-1)), low mixing height (<200 m) and high relative humidity (>90%).