In this work level of Polycyclic Aromatic Hydrocarbon (PAHs) from indoor Environment Tobacco Smoke (ETS) of pubic bars in Nigeria was investigated. Indoor air samples were obtained from different public bars using Polyurethane foam (PUF) passive samplers. Analysis of PAHs was carried out using GC-MS operated in selected ion monitoring mode. Result showed the average concentration range of 2.71-9.69 ng/m³ while the ∑ 16 PAHs range from 43.43 to 155.11 ng/m³. The incremental lifetime cancer risk (ILCR) values from inhalation of PAHs in these bars ranged from 2.4×10^-7-5.2×10^-7 while non-carcinogenic risk, Hazard Quotient (HQ) ranged from 2×10^-4-4.5×10^-4. Although these values are lower than WHO permissible limit, nevertheless the study underscores the danger associated with the inhalation of ETS in the public bars in Nigeria.

As part of research efforts to investigate the contribution of various anthropogenic activities to local atmospheric pollution load across Nigeria, the study investigated emission of air pollutants from the combustion processes in Lagos mega city. Solid wastes, consumption of fuel wood, and petroleum products were identified as major materials being combusted in Lagos and these materials were quantified based on the information in literature. Annual emissions from the combustion of the quantified materials were estimated using emission factor approach. The total estimated annual contribution of anthropogenic combustion processes to atmospheric loading of PM₁₀, CO, SO₂, NO_x and VOC were 188.49, 5920.97, 11.24, 348.88 and 4.14 kt/annum, respectively. Emissions from the combustion of solid waste/biomass were identified as a major source of criteria air pollutants in the city because, about 67.5% and 82% of the estimated CO and PM₁₀ emissions, respectively, were generated from the combustion of solid waste/biomass. Also, 81%, 57% and 32% of NO_x, SO₂ and CO emissions respectively were found to have emanated from combustion of kerosene. These elevated emission levels can be said to have potential impacts on ambient air quality of the study area. The study concluded that immediate mitigating action to reduce release of pollutants from combustion processes should be put in place.

The acceptance of liquefied petroleum gas (LPG) cookstove has increased across the country in recent years; however, their performance has not been investigated and established. To achieve this, laboratory tests were carried out to evaluate the thermal efficiency, and industrial combustion analyser (E-instrument E8500) was then used to characterize and quantify the air emissions from combustion of conventional LPG cookstoves in the country. The average thermal efficiency for all tested burners was 66.267 ± 7.218% meeting Tier 4 of the International Organization for Standardization, International Workshop Agreement 11. The mean concentration of CO, NO_x, HC, and SO₂ was in the range of 3–530, 48–810.5, 99–4176, and 0–4,respectively,and the range of CO₂ was 1,792–3,592 mg/m³,which were compared with stationary source limit by Federal Ministry of Environment Standard, Nigeria. The toxicity potential of NO_x and SO₂ was below unity, 25% of the burners tested were below unity for CO, and HC was higher than unity for all tested burners. Most cookstoves met the guidelines for CO, NOx, and SO₂. Hence, LPG in Nigeria could serve as a source of energy for cooking.

Purpose: Recent developments in the electricity generation sector of Nigeria necessitated the re-assessment of its contribution to air emission level in the country as information provided by previous inventory is nearly out-of-date. The purpose of this paper is to quantify the carbon dioxide (CO₂) emissions generated from existing thermal power plants in the country.Design/methodology/approach: Thermal power plants in Nigeria and their installed capacities were identified, and estimation of CO₂emission from each of the plants was carried out using the emission factor method. In addition to the direct emissions generated through the combustion operation of the power plants, indirect emissions resulting from upstream activities such as extraction, production, and transportation of fuels consumed by the thermal power plant was determined using the same method.Findings: In total, 40 thermal power plants are currently operational in Nigeria. Additional 18 thermal plants are at different stages of completion. The operational thermal plants have average generation output of 40 percent of their installed capacity and produce 87.3 million metric tonne (mmt)/annum CO₂emissions. In total, 66.9 percent of the estimated emissions are direct emissions, i.e. fuel combustion emissions; the rest are indirect emissions. Additional 67.9 mmt was estimated as expected overall emissions from the thermal power plants under construction. Considering the global warming potential of CO₂, proactive measures must be taken to regulate its emissions from the country’s thermal power plants.Originality/value: This paper bridged the information gap existing in the emission inventory from the Nigeria electricity sector by providing up-to-date data on the contribution of the sector to greenhouse gas emission level in the country.

The indoor air quality (IAQ) is paramount to the existence of humans considering the amount of time spent indoors. The indoor pollutant levels may be 100 times the levels outdoors. The indoor pollutants need to be considered to enhance better IAQ. This study determined the emission factors of carbon monoxide (CO) emitted from a standby electricity generator (SEG). It evaluated the impacts of CO concentrations on indoor air quality and identified appropriate ways to mitigate the CO concentrations. The indoor CO concentration was determined by simulating a number of scenarios of SEG operated outdoor using a Simulation Tool Kit for Indoor Air Quality and Inhalation Exposure (IAQX) model. Hourly measurements of mean CO concentrations in the ambient environment and wind speed were conducted for four weeks in four field locations. The emission rate of CO from the standby electricity generator was measured. The CO concentration from SEG was 2.4289 × 10⁴ mg/m³, a very high CO concentration. The CO emission factors were obtained as 2.2366 × 10³ kg/m³ of fuel consumed and 9.5411 × 10⁶ kg/hr of activity. High CO concentrations were obtained in microenvironments from the scenarios 1.28 × 10⁴ mg/m³, 4.78 × 10³ mg/m³, 4.79 × 10⁴ mg/m³ and 9.58 × 10⁴ mg/m³. The results showed that a high air exchange rate allowed CO concentrations to decay fast while low air exchange rates created an accumulation of CO concentrations indoor.

This work generated data on the emission factors of air emissions from combustion of woody biomasses collected from southwest, Nigeria. This was with a view to finding their potentials as sustainable and environmentally friendly fuels for firing thermal power plants compared to coals. The data on heating values and elemental contents (carbon, sulphur and nitrogen) responsible for gaseous emissions in the 100 woody biomasses were collected from the previous results of this work to determine the gaseous emission factors on the expected condition of complete combustion. The current results showed that the CO2 emission factors ranged from 0.0147 kg/(MJ/kg) for Ficus mucuso to 0.1499 kg/(MJ/kg) for Spondias mombin, SO2 emission factors ranged from 0.0000000 kg/(MJ/kg) for Pterygota macrocarpa, Irvingia grandifolia, and fifteen others, to 0.0011341kg/(MJ/kg) for Khaya ivorensis, while NO2 emission factors ranged from 0.0000000 kg/(MJ/kg) for Citrus medica to 0.0035824 kg/(MJ/kg) for Ficus carica. Considering the minimal emissions from biomasses compared to coal species, serious political will is needed on the part of the Nigerian government to propagate these biomasses for fuels in firing the thermal plants in the country.