Browsing by Author "Sonibare, J.A."
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Item Air quality impact of diesel back-up generators (BUGs) in Nigeria’s mobile telecommunication base transceiver stations (BTS)(Emerald Insight, UK, 2017) Adeniran, J.A.; Yusuf, R.O.; Amole, M.O.; Jimoda, L.A.; Sonibare, J.A.Purpose – The introduction of mobile telecommunication services in Nigeria led to the development of base transceiver stations (BTS) across the country. Inadequate power supply from the national grid has led to massive use of diesel-fueled back-up generators (BUGs). The purpose of this paper is to attempt to quantify and inform relevant stakeholders about air quality implications of BTS BUGs. Design/methodology/approach – Seven major telecommunication network operators were identified. Emission factor approach was used to estimate the quantity of important air pollutants such as NOx, CO, SO2, PM10, PM2.5, PAH and TVOC that are emitted from the use of the BUGs based on fuel consumption rate and generators’ capacity. Fuel-based emission inventory and emission factor from the United States Environmental Protection Agency AP-42 and National Pollution Inventory were used to estimate pollutants emission from diesel-powered generators used in the BTS sites and amount of diesel consumed. Land distribution and per capita dose of the estimated pollutants load were calculated. Findings – The study showed that the deployment of BUGs will lead to increase emissions of these air pollutants. The states that are most affected are Lagos, Kano and Oyo, Katsina and Akwa Ibom states with respective total air pollutants contribution of 9,539.61, 9,445.34, 8,276.46, 7,805.14 and 7,220.70 tonnes/yr. Originality/value – This study has estimated pollutant emissions from the use of diesel-fueled BUGs in mobile telecommunications BTS sites in Nigeria. The data obtained could assist in policy making.Item Analytical modeling of human exposure from short-term point source releases of aerosols from household spray products(Taylor and Francis, 2018) Adeniran, J.A.; Araromi, D.O.; Yusuf, R.O.; Oke, E.O.; Sonibare, J.A.Indoor air measurements of aerosols emitted from the use of household spray products are expensive and time-consuming. An analytical model was developed and incorporated into a graphical user interface to quantify exposure as a function of distance and time. The model considered point source dispersion with reflection from a wall and aerosol concentration decay due to air exchange rate and deposition. Aerosol concentration decreased with respect to increase in time and distance from the release point. There was no significant difference between the developed model and experimental results. The developed model could be used to adequately predict indoor human exposure to aerosols as a function of distance and time.Item Exposure to total volatile organic compounds from household spray products(Kaunas University of Technology, 2017) Adeniran, J.A.; Yusuf, R.O.; Mustapha, S.I.; Sonibare, J.A.Emission of volatile organic compounds from the use of household spray products has a negative impact on health and environment. Total volatile organic compound (TVOC) concentration levels emitted from 45 registered consumer spray products in Nigeria were measured using the MultiRAE TVOCs gas monitor. Human exposure to emitted TVOCs through inhalation, ingestion or through the dermal route was evaluated using the ConsExpo spray model. The average TVOCs emission from all the investigated samples was in the range of 1,664 and 560,994.7 μg m-3 with an average of 63,632.2 μg m-3. Generally for all the samples considered, the average released concentrations, the inhaled doses, the dermal doses, and the average deposition rates values obtained were in the ranges of 1.83E+04 – 1.00E+06 μg m-3; 1.47E+03 – 8.01E+04 μg; 3.41E+04 – 4.84E+05 μg; and 1.79E+01 – 1.01E+03 μg s-1, respectively. The results provide information that could be used to significantly improve human exposure and risk assessment to emitted aerosols from spray products.Item Ground level Concentration of some air pollutants from Nigeria thermal power plants(Taylor and Francis, 2016) Adesanmi, A.J.; Adeniran, J.A.; Fakinle, B.S.; Jimoda, L.A.; Yusuf, R.O.; Sonibare, J.A.Power sector in Nigeria is undergoing structural reforms aimed at improving and expanding the current generation capacity, using thermal power plants. Ground level concentrations of air pollutants emitted from natural gas-powered thermal power plants were estimated using the American Meteorological Society-Environmental Protection Agency Regulatory Model (AERMOD). The average 24-h ground level concentrations of CO, NOx, SO2, particulate matter (PM), and volatile organic compounds (VOCs) were 31.88–72.79; 61.33–104; 0.61–3.91; 0.21–1.52; and 0.19–1.09 ìg/m3, respectively. There is need for continuous monitoring of ground level concentration of pollutants around the thermal power plants to guarantee the safety of the environment in the host communities.Item Optimization and performance evaluation of environmentally friendly rocket composite propellant(Taylor and Francis, 2018) Gbadebo, O.A.; Adeniran, J.A.; Adesanmi, A.J.; Akeredolu, F.A.; Sonibare, J.A.This paper investigated the effects of laboratory synthesised rocket composite propellants’ formulations on propellant performance parameters using response surface methodology (RSM). For the sake of a safe environment, the propellant is made of chemical constituents that have less severe effects on air quality. Experimental measurements of propellant performance parameters were carried out using the ballistic evaluation method. The thrust generated during combustion, the burn time and the propellant combustion temperature were measured using a data acquisition facility equipped with a button load cell and a thermocouple. Specific impulse, density, temperature, characteristic velocity, molecular weight and heat ratio were computed from the measured parameters. The resulting optimum rocket composite propellant formulations were 65.1%, 18.1%, 9.1%, 3.6%, 2.2% and 1.9% for the oxidiser, binder, fuel, opacifier, burning rate enhancer and catalysts, respectively. The corresponding performance indices including specific impulse, propellant density, propellant temperature, propellant characteristic velocity, molecular weight and heat ratio were 122.03 s, 1697.08 kg m-3, 2025.07 K, 987.65 m s-1, 31.50 kg mol-1 and 1.02, respectively. Findings revealed the accuracy and the adequacy of RSM in analysing and optimising the effects of composite rocket propellant formulation on its performance parameters and also a step towards producing an environmentally friendly rocket composite propellant.Item Spatiotemporal distributions of polycyclic aromatic hydrocarbons close to a typical medical waste incinerator(Springer, 2018) Adesina, O.A.; Sonibare, J.A.; Diagboya, P.N.; Adeniran, J.A.; Yusuf, R.O.hydrocarbons (PAHs) especially from incinerators occur subtly, and PAH contribution from this source is underestimated. However, as environmental PAH concentrations build up, this may be a serious concern around the incinerator vicinity due to the potential consequences of PAHs on ecosystems and human health. Thus, the contribution of selected (12) PAHs from the Obafemi Awolowo University Teaching Hospital medical waste incinerator (or source, HWI_0) was determined by sampling stack gas and ambient air around incinerator vicinity from June 2014 to May 2015. Results showed that the 12 PAH source (HWI_0) concentrations were in the range of NA (for phenanthrene, pyrene, anthracene, benz[e]acephenanthrylene, and indeno[2,1- b]chromene) to 10.9 ng/m3 (pyrelene) and generally higher than the receptor points (hospital waste incinerators (HWIs)). The average total PAH concentrations per month at HWI_0 and the receptors—HWI_1, HWI_2, HWI_3,HWI_4 and HWI_5—were 73.0 ± 27.9, 60.4 ± 30.8, 42.5 ± 23.6, 38.7 ± 21.9, 35.0 ± 27.2, and 39.2 ± 22.9 ng/m3, respectively. These results and multivariate receptor model analysis indicated high correlations between source PAH contributions and the receptor points. The PAH concentrations in the dry season were higher than the wet season suggesting that hydrological condition affects ambient PAH concentrations. The average PAH concentrations in the HWIs as well as the cumulative exposure concentrations observed throughout the period are of major health concern because PAH concentrations detected are several times higher than both the European Union standard and the WHO guideline level.