Measurements and Modeling of Emissions from Biomass Combustion Sources in North-central Nigeria

Abstract

This work is aimed at monitoring and analyzing the concentrations of gaseous pollutants such as Carbon (II) oxide, Sulphur (IV) oxide and Hydrogen sulphide and Particulates (PM₂̣ ₅ and PM₁₀) released from biomass combustion sources at specified receptor points downwind. A real time analysis was adopted in monitoring these pollutants by the use of ALTAIR Multi- gas detector and HAT 200 PM₂̣ ₅ and PM₁₀ detector. The estimated emission rates of 140mg/s and 84mg/s for CO, 0.744mg/s and 0.714mg/s for SO₂̣ and 1.556mg/s and 1.176mg/s for H₂̣S were respectively obtained for charcoal and wood burning sources. This could be attributed to the source geometry and the combustion conditions of these combustion sources. An analysis of the base line monitored concentration depicts wood burning sources as having maximum concentrations of 113.58mg/m³, 1.01mg/m³, 1.74mg/m³, 0.70mg/m³ and 1.55mg/m³ for CO, SO₂̣, H₂̣S, PM₂̣ ₅ and PM₁₀ respectively while the minimum concentration of 1.20mg/m³, 0.03mg/m³, 0.07mg/m³, 0.11mg/m³ and 0.24mg/m³ were monitored for CO, SO₂̣, H₂̣S, PM2.5 and PM10 respectively from the same sources within their microenvironments (1.0-5.0m). Also, a further consideration of the baseline monitored concentration obtained from charcoal emissions presents the maximum concentrations of 153.92mg/m³, 0.56mg/m³, 1.25mg/m³, 0.05mg/m³ and 0.11mg/m3 respectively for CO, SO₂̣, H₂̣S, PM2.5 and PM10 while the minimum concentrations of 6.24mg/m³, 0.18mg/m³, 0.07mg/m³, 0.03mg/m³ , and 0.06mg/m³ respectively for CO, SO₂̣, H₂̣S, PM2.5 and PM10 were monitored within the microenvironments (1.0-5.0m) of charcoal emission sources. Based on National Ambient Air Quality Standards, it is observed that the safe distance for human health around these biomass combustion sources is any distance greater than 4.0m for CO (1 hour time average, the safe limit is 40mgm-3), SO₂̣ (24 hour time average, the safe limit is 0.365mgm-3) and H₂̣S (1 hour time average, the safe limit is 0.042mg/m³). It is then suggested that for minimal deleterious effects on people around these emission sources, duration of activities around them should be reduced and those involved in these activities (e.g cooking) should position themselves at the anti-plume direction.