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This study investigated the contribution of anthropogenic emission of benzene from petroleum refineries to the Nigerian’s ambient air quality with the view of understanding the impact of petroleum production facilities on host airshed. The Activities of the four existing and 22 proposed petroleum refineries in Nigeria were obtained from the Department of Petroleum Resources and these were combined with emission factors of different units at the refineries to estimate benzene emissions. No-control-measure option (worst case scenario) was assumed because of lack of information on control efficiency of the refineries. The study revealed that two of the existing refineries in one of the oil-producing cities in Nigeria released a total of 10.01 × 1011 tons/year of benzene into the ambient air of the city, apart from additional 2.35 × 1013 tons/year anticipated to be released from three of the proposed refineries into the ambient air of the same host community. If operated at full capacity, the estimated benzene emission from the four existing refineries stood at 5.50 × 1013 tons/year while the 22 proposed refineries have the capacity of releasing additional 16.73 × 1013 ton/year. On the overall, the contribution of benzene from refineries on yearly basis to Nigerian airshed was estimated to be 22.24 × 1013 tons. These concentrations if not checked could lead to devastating environmental issues. Some mitigating measures were suggested to control and subsequently abate benzene emission from these refineries.

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, NOx 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 NOx, 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, NOx, 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 NOx 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.

This paper estimated the annual levels of sulphur dioxide (SO2) from consumption of premium motor spirit (PMS) and automotive gas oil (AGO) across the States and Regions of Nigeria. This was with a view to estimating the per capita and land distributions of emissions. Annual fuel consumption, average fuel sulphur contents and emission factors were combined to estimate the annual levels of SO2. Per capita and land distributions of emissions were then established using population and land area, respectively. Results showed that Lagos and Ogun States had the maximum SO2 emissions from consumption of PMS and AGO, respectively, in 2012. Between 2001 and 2014; most of the SO2 emissions from consumption of PMS and AGO came from the South-western and South-southern regions of the country, respectively. Based on projected future fuel consumption, annual SO2 emissions from utilization of PMS and AGO are projected to further increase over their 2014 estimates. Interim measure suggested for mitigation of SO2 emission is the importation of refined products with highly reduced sulphur contents. Medium to long-term measures include building of more refineries locally to make use of Nigeria’s crude oil which is generally low in sulphur content and a massive improvement in the country’s energy generation so as to lower the demand pressure on refined petroleum products.

This study examined the ambient levels of criteria air pollutants in the indoor and outdoor environment of a typical hospital facility. Ambient concentration of the criteria pollutants was monitored at nine sampling locations using the ToxiRAE gas monitors both in the rainy and dry seasons. The results showed that the overall 24-h concentrations for CO and NH3 were 0.18 ± 0.19 and 0.11 ± 0.13 ppm, respectively, for dry season. During the wet season, the extrapolated 24-h concentrations ranged 0.09–1.09 ppm for CO, 0.04 ± 0.08 ppm for NH3 while NO and NO2 had 0.03–0.21 ppm and 0–0.06 ppm, respectively. The result of the study shows that the 24-h NH3 concentration of 0.44 ppm recorded at S5 during dry season breached the National Air Quality Standards of the Federal Ministry of Environment Standard, Nigeria. Similarly, NO and NO2 levels were higher than other gaseous parameters measured in all the sampling locations during the wet season. This study establishes that human activities may have deleterious effect on air quality in the hospital airshed.

Urban air pollution continues to be a major problem in Nigerian cities. Most studies of air pollution in Nigeria have concentrated on the background air quality and its effects on people outside vehicles. However, it has been suggested that in-vehicle pollution is often worse than pollution outside the vehicle. This study focuses on personal exposures to PM10 and PM2.5 in various modes of transportation in Lagos city. Six roadways which are representative of commercial, industrial, and residential areas of the city were selected. Measurements were made inside four major modes of transportation in the city: cars, buses, Bus Rapid Transit (BRT), and walking for PM10 and PM2.5. Measurements were done for each mode twice a day (morning and afternoon) for 12 days. The highest average PM10 and PM2.5 concentrations were measured for pedestrian (476.35 and 216.60 μg/m3, respectively) during rush hours. The result showed that pedestrians were found to be exposed to the highest average PM10 and PM2.5 concentrations, while commuters in cars, BRT and buses were exposed to respective decreasing concentrations of PM10. Similarly, commuters in BRT were exposed to the lowest concentrations of PM2.5 regardless of time of day. The results obtained were much higher than the results for London but comparable to Mexico city and Taiwan’s results. This study has provided information that can help commuters to choose appropriate travel behavior that can minimize their exposure to particulate matter.