Quantifications and predictions of sectoral pollutants emissions in Nigeria from 1980 to 2050.

The fast-economic development and population growth in Nigeria have resulted in huge quantities of air pollutants emission which have implications on the environment. Detailed sectoral emission inventory to serve as the basis for policy formation to mitigate the condition is still lacking. This study builds detailed sectoral emission inventory using the emission factor approach to estimates various pollutant emissions from different sources. Five major sources of pollutant emissions were identified which include transportation, energy, municipal solid waste, wood fuel, and agricultural sectors. An increasing trend in emissions from 1980 to 2020 was observed for total emission of CO, NOx, PM2.5, PM10, SO2, NH3 and NMVOC in Nigeria that increased from 1 736-6 210; 143-338; 126-551; 171-717; 19-60; 4-28; and 471-1 587 Gg, respectively. Wood fuel, transportation, and municipal waste sectors are the major sources that contributed to 63%, 16%, and 15% of the total CO emission. Three mitigation scenarios for emission reduction for the future were analyzed. CO emission reductions of 38%, 24%, and 38% will be obtained from the liquefied petroleum gas (LPG) intervention, waste to energy (WTE) technology, and vehicle inspection and maintenance (VIM) policy scenarios, respectively, through to the year 2050.

Indoor transmission dynamics of expired SARS-CoV-2 virus in a model African hospital ward.

Cough and sneeze droplets' interactions with indoor air of a typical hospital clinic that could be majorly found in developing African countries were studied to investigate the effectiveness of existing guidelines/protocols being adopted in the control of the widespread coronavirus disease (COVID-19) transmission. The influences of indoor air velocity, the type, size distribution, residence time in air, and trajectory of the droplets, were all considered while interrogating the effectiveness of physical distancing measures, the use of face covers, cautionary activities of the general public, and the plausibility of community spread of the SARS-CoV-2 virus through airborne transmission. Series of 3-D, coupled, discrete phase models (DPM) were implemented in the numerical studies. Based on DPM concentration maps as function of particle positions and particle residence times that were observed under different droplets release conditions, the virus-laden droplets could travel several meters away from the source of release (index patient), with smaller-sized particles staying longer in the air. The behavior of indoor air was also found to indicate complex dynamics as particle transports showed no linear dependence on air velocity. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40201-020-00606-5.

Investigation of air emissions from artisanal petroleum refineries in the Niger-Delta Nigeria.

The increase in price of the available refined petroleum products for local consumption in Nigeria had led to the emergence of indigenous technology for petroleum refining in some parts of the Niger Delta region. This study, therefore characterized and quantified artisanal refineries' gaseous emissions for possible air pollutants based on various unit operations involved and evaluated their impacts. It measured the emissions directly from source using E8500 Portable Combustion Analyzer. It also categorized oven sizes/processing capacity of the refineries into various ranges in order to estimate emissions according to processing capacity. The result revealed that; pollutants emission varied significantly between the unit operations and increased with increase in processing capacity. When the emissions were compared with daily limits set by the Environmental Guidelines and Standard for Petroleum Industry in Nigeria (EGASPIN) 2002, the emissions (CO, NOx, and SO2) breached the available set limits. While with the Federal Environmental Protection Agency (FEPA), 1991 set limits for emissions from stationary source; HC and CO breached their limits. SO2 and H2S breached their lower limits but were below the upper limit, while NOx emissions were found within its set limit. The study concluded that, Nigeria Artisanal Petroleum Refineries are sources of air pollution, as they impact the host environment.

Emission factors of some common grass species in West Africa.

Frequent burnings occurring in the grasslands of the West African region during the dry seasons largely contribute to emissions of trace gases and particulates being released into the ambient environment, which has significantly impacted both regional and global climate patterns. Burning potentials of forty different grassland biomes were examined by determining their Net Heating Value (NHV) and Total Organic Carbon (TOC). Simulations of the field operations which involve open burning were performed in the laboratory using a fabricated combustion chamber for the determination of emission factors. Particulates were collected using Whatman quartz fibre filters and analyzed gravimetrically. Emissions of gaseous pollutants from open burning of these common grass species were measured with portable devices. The values of the NHV and TOC of the grass species ranged from 15,022.19 to 18,181.84 kJ/kg and 21.14 to 55.62%, respectively. The average Emission Factors (EFs) obtained for carbon dioxide (CO2), carbon monoxide (CO), sulphur dioxide (SO2), nitrogen dioxide (NO2), volatile organic compounds (VOC), and PM2.5 are 1465.55 g/kg, 40.99 g/kg, 0.39 g/kg, 0.02 g/kg, 7.78 g/kg, and 6.00 g/kg, respectively. The study has shown that Digitaria nuda, Digitaria eriantha, Panicum subalbidum, Paspalum polystratchyum, and Perotis indica have the highest emission factors for CO2, CO, SO2, NO2, VOC, and PM2.5, respectively. The result obtained would help in the quantification of the global warming forcing on the climate in the West African region from grassland burnings. The results will potentially serve as additional information for emission inventories and basis for the formulation of mitigation strategies.

Evaluation of emission indices and air quality implications of liquefied petroleum gas burners.

Major cities in Nigeria has adopted the use of liquefied petroleum gas (LPG) as their main source for domestic cooking, however, this adoption led to different designs of LPG burners in Nigeria market. The emission indices of these burners and their air quality implications are yet to be ascertain. To solve these problems and fill the data gap, laboratory analysis were carried out on 16 conventional LPG burner heads identified in Nigeria market. The emission factors for Carbon monoxide (CO), Oxide of Nitrogen (NOx), Carbon dioxide (CO2), Hydrocarbons (HC) and sulphur dioxide (SO2) on the basis of useful energy delivered were 0.123-21.784 g/MJd, 1.973-32.943 g/MJd, 73.819-147.639 g/MJd, 4.069-171.643 g/MJd and 0-0.1644 g/MJd while the emission rates were 0.000238-0.1125 g/s, 0.0071-0.2 g/s, 0.1083-0.7 g/s, 0.0117-1.2583 g/s and 0-0.000194 g/s respectively. It was observed that results from the study were within the International Organization for Standardization, International Workshop Agreement 11 and World Health Organization indoor air quality guidelines for human protection.

Evaporation rates and pollutants emission from heated cooking oils and influencing factors.

The heating of edible oils during cooking activities promotes the emissions of pollutants that have adverse impacts on the health of humans. This study investigated the evaporative emissions of fifteen (15) commonly used cooking oils. Split-plot experimental design under the response surface methodology framework was used to study singular and interaction effects of influencing parameters (temperature, volume of cooking oil and time) on cooking oil evaporation rate and pollutants emissions (i.e. Particulate matter of aerodynamic diameter ≤1 µm (PM1.0); ≤2.5 µm (PM2.5); ≤10 µm (PM10); Total Suspended Particulate (TSP); Total Volatile Organic Compounds -TVOCs, and Carbon Monoxide- CO) on a groundnut oil sample that served as a case study. Obtained values of density, viscosity, kinematic viscosity, smoke, flash and fire points were; 873-917 kg/m3; 1.12-9.7 kg/ms; 2.4-3.4 m2/s; 96 -100 °C; 124-179 °C and 142-186 °C, respectively. The role of temperature as the most significant parameter influencing the rate of evaporative emissions was established. Evaporation rate and pollutants emission from unrefined samples were the highest. The restricted maximum likelihood (REML) analysis results suggested a strong relationship between the actual values and the predicted values as R-squared values obtained were greater than 0.8 for all the responses. These results suggest that minimal rates of evaporation and pollutants emission from heating cooking oils can be achieved with a high volume of the cooking oil at moderate temperature levels.

Impact of elemental composition of particulate matter in the airshed of a University Farm on the local air quality.

The impact of particulate matter on the ambient air quality of Landmark University Farm was assessed using deposition fluxes of Trace elements (TEs) in the airshed of the farm. Deposition gauges were employed to collect both dry and wet deposition samples of particulate matter between 2018 and 2019. Elemental compositions of particulates collected during the sampling period were analyzed using Energy Dispersive X-ray Fluorescence Spectroscopy (ED-XRF). The deposition fluxes of crustal and anthropogenic trace elements were also determined using standard methods. Results showed that in dry season, iron has the highest mean concentration (3283.61 mg/kg), while chromium has the lowest (0.023 mg/kg). On the other hand, in wet season, silicon and nickel have the highest and lowest mean concentrations of 159.34 mg/kg and 0.01 mg/kg respectively. Although the concentrations of these metals were higher in the dry season than wet season, there was no statistical significant difference between the mean concentrations of the elements measured in each season of the year (p > 0.05). The compositions of some of the elements in the particulate matters were found to be far above the recommended exposure limits prescribed by OSHA. The study concluded that the elemental composition of particulate matter in the airshed of the University Farm adversely impacts the ambient air quality of the Community.