Risk Assessment of Toxicity Potential for Criteria Ambient Air Pollutants in Selected Areas of Lagos State Nigeria.

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Department of Geography, Osun State University, Osun State, Nigeria


The quality of ambient air is determined by the extent of pollution of the environment. The United State Environmental Protection Agency identifies six criteria pollutant namely particulate matter, ground level ozone, carbon monoxide, sulphur oxides, nitrogen oxides and lead exposure as toxic and injurious because of their potentials to cause or trigger various human health problems. This study examines the toxicity potential of criteria ambient air pollutants in selected areas of Lagos State, Nigeria. The data for the study include five year data of criteria pollutants for selected areas of Lagos and World Health Organization (WHO) guideline values of criteria pollutants. Data analysis adopted the use of Toxicity Potential model for the calculation of the toxicity potential of the criteria pollutants. GIS procedure was employed to produce a maps showing the spatial pattern and hotspot areas of criteria pollutants. Criteria pollutants in the study area were also compared with the WHO standard with a view to determining areas of excessive pollution and toxicity potential in the area. The study reveals that PM2.5, PM10, SO2 and NO2 in Lagos areas clearly exceeded the benchmark set by WHO. Furthermore, CO and O3 are well below the WHO standards. The toxicity potential values for PM2.5, PM10, SO2 and NO2 in the area of study are greater than unity while the values for CO and O3 are lesser than unity which indicates that such concentration has a tendency of causing harm to people and hence should be avoided. The study recommends that governments, and other stakeholders in health should harmonize efforts, resources and ideas towards effective planning, monitoring, and provision of facilities that could control and ameliorate the presence of these pollutants to which urban residents are exposed thereby reducing the health effects from such exposures.



Ambient air, Pollution, Health, Toxicity, Criteria pollutants