Off-grid gasoline-powered generators: pollutants' footprints and health risk assessment in Nigeria

Sub-Sahara Africa is renowned for poor electricity supply with Nigeria's case being critical. Generator sets, which have been adopted as an alternative and reliable source of power in Nigeria, are linked to emission footprints detrimental to the environment and human health. The dearth of literature in open domain on the concentrations of pollutants and potential health risk related to the use of gasoline-fueled generators prompted this study. Concentrations of CO2, CO and particulate matter (PM2.5) emitted from selected randomly 174 gasoline-powered household generators were measured. Standard instruments were employed to measure these concentrations at 0.3-0.5 m from the exhaust pipe for 1 h (at 10 mins interval). The study area was Sango, Ogun State, Nigeria. The obtained results were 710 +/- 19.1 ppm, 83 +/- 4.0 ppm and 83 +/- 4.1 mu g/m(3) (average) for CO2, CO, and PM2.5, respectively. The regression analyse carried out on the data for the age and efficiency of the generators in relation to the concentration data of CO2, CO and PM2.5 showed that the efficiency (R = 0.92 and F = 301.3) has more impact on the concentrations than the age (R = 0.68 and F = 49.6). Also, the efficiency of the generators was observed to have positive and significant effect on both the CO2 (t-stat = 10.05 and P-value = MUCH LESS-THAN 0.050) and PM2.5 (t-stat = 2.26 and P-value = 0.025) concentrations. The average concentrations of CO2 and PM2.5 were observed to be higher than those recommended by the World Health Organization. Health impact assessment revealed hazardous and unhealthy status for CO and PM2.5 with air quality indices of >500 and 178.8, respectively. This study recommends efficient use of generators, fuel switching (gasoline to LPG), stringent emission measures and use of renewable energy as possible solutions.