Longitudinal survey and health risk assessments of toxic emissions from artisanal refineries in the Niger Delta: An empirical evidence of Bayelsa State, Nigeria

Abstract

The study looks at toxic emissions from artisanal crude oil refining operations in Bayelsa State, Nigeria, using a longitudinal survey. Five key air pollutants; Carbon monoxide (CO), Nitrogen oxides (NOₓ), Sulfur oxides (SOₓ), Fine particulate matter (PM_2.5), and Coarse particulate matter (PM₁₀) were monitored across four randomly selected sites over several months. Portable monitors were used to evaluate air quality; the United States Environmental Protection Agency's (US-EPA) Air Quality Modeling Index (AQI) was used to determine health hazards. Results revealed that the CO levels varied from 0.001 to 0.021 µg/m³, with the highest at site LB in August. Ranging from <0.001 to 0.014 µg/m³, NOx peaked at site LC in April. Ranging from <0.001 to 0.090 µg/m³, the SO_X showed highest levels at site LA in August. With the most at site LB in June, fine particle pollution (PM_2.5) levels varied from 14.91 to 25.05 µg/m³. Ranging from 26.52 to 45.73 µg/m³, coarse particulate matter (PM₁₀) was highest at site LD in April. Although many pollutants stayed within safe limits, moderate amounts of CO and PM₁₀ at particular locations created health concerns for sensitive populations. Particularly at site LC, the findings underlined spatial and temporal differences in pollutant levels. Though usually good, the air quality in the Niger Delta is affected by moderate amounts of certain offensive emissions, which justifies ongoing monitoring and regulatory action to safeguard public health.