Bamidele Sunday Fakinle

Air pollution control is a safe method for achieving a sustainable environment and can be accomplished by adequately monitoring pollutants that pose significant environmental risks. The combustion of sulfur-containing petroleum products has been a major concern for several decades. Therefore, this study was aimed at determining sulfur levels in refined petroleum products such as Premium Motor Spirit (PMS), Automotive Gas Oil (AGO), and Dual-Purpose Kerosene (DPK). It also investigated the air quality implications of sulfur levels and estimated the contribution of the refinery’s products to sulfur dioxide air emission. Fuel samples were collected from the Warri Refining and Petrochemical Company (WRPC) in Nigeria and analyzed using Ultraviolet-visible spectrophotometer (UV-Vis) and Energy-Dispersive X-ray Fluorescence (EDXRF). Sulfur levels were determined at 425 nm wavelength, and sulfur dioxide air emission were estimated for seven consecutive years from 2010 to 2016 using the emission factor approach. The densities of PMS, AGO, and DPK were 0.77 kg/l, 0.832 kg/l, and 0.82 kg/l respectively. The levels of sulfur in PMS, AGO, and DPK were 2.007 x 10^-4 %, 6.970 x 10^-5 wt%, and 4.233 x 10^-5 wt% respectively from UV-Vis technique and 0.016, 0.087 and 0.029% respectively for EDXRF technique were found below the sulfur limit of 0.015 %, 0.005 % and 0.015 % for PMS, AGO and DPK respectively specified by Standard Organization of Nigeria (SON) specifications of 0.1, 0.5 and 0.15wt% for PMS, AGO and DPK respectively. The annual sulfur dioxide emissions were obtained for seven consecutive years from 2010 to 2016. The results from UV-VIS were observed to have the highest SO₂ emission of 0.1718 tons for PMS in 2011, 0.2593 tons in 2010 for AGO, and 0.0974 tons for DPK in 2010, while the lowest emission was observed to be 0.029 tons for PMS in 2015, 0.0362 tons in 2015 for AGO and 0.0181 tons for DPK also in 2015. The results from EDXRF technique were observed to have the highest SO₂ emission of 13.6939 tons for PMS in 2012, 323.6881 tons for AGO in 2010, and 66.7147 tons for DPK also in 2010, while the lowest emissions for PMS, AGO and DPK were all observed in 2015 to be 2.3122, 45.1872, and 12.4182 tons respectively. The study concluded that the refinery complied with the set requirements.

Due to the presence of corrosive contaminants in the air, metals naturally corrode when exposed to the environment. Air pollution, in conjunction with climate conditions, may significantly deteriorate outdoor materials, especially metals and hence, the need for corrosion control. Using inhibitors is a powerful strategy that is frequently employed for corrosion prevention and control. Chemical inhibitors are often used. However, due to their low effectiveness and stringent environmental regulations, the majority of chemical corrosion inhibition techniques are becoming less desirable. For this reason, there is an increasing interest in and focus on biological inhibition approaches, which most recently have included the use of microbes. Microbiologically-influenced corrosion inhibition (MICI) is apparently far more complex than traditional corrosion inhibition procedures. A current overview of the mechanisms that have been used or may be efficient for MICI technologies is important in order to facilitate the advancement of MICI and its practical industrial applications, especially for atmospheric corrosion caused by air pollutants, for which there is little information in the reviewed literature. Therefore, this review addresses the role of microbes, like Pseudomonas putida, in the inhibition of atmospheric corrosion of metals and brings the reader up-to-date on the few literatures existing on the subject. The review describes and characterizes MICI for atmospheric corrosion as a developing field still in need of enthusiastic researchers to further investigate the area in order to establish useful methodologies, procedures, and technologies for later adoption in industrial terrains and applications.

Emissions of components of VOCs from combustion of agro-waste materials were quantified. Agro-waste materials comprising corn cobs, corn husks, bean chaff and rice husks were burnt at a temperature of 400°C in a muffle furnace, and the emissions were quantified according to standard procedures. Health risk associated with exposure to the emissions, based on carcinogenicity and non-carcinogenicity, was evaluated using excess lifetime carcinogenic risk (ECLR) and hazard quotient (HQ), respectively. The results showed identification of 11 compounds comprising undecane, benzene, bromoform, ethylbenzene, styrene, toluene, p-xylene, 1,3-dimethylbenzene, o-xylene and phenol. The concentrations of the identified compounds ranged from 0.01 to 7.35 µg/m³, with chlorobenzene (emission from corn cobs) having the highest concentration and 1,3-dimethylbenzene having the lowest concentration (across all samples). The results also showed that ELCR and HQ values were below the recommended levels. The result concluded that although short-term exposures to the emission from combustion are not likely to cause health issues, prolonged exposure should be avoided as this could complicate issues for individuals with existing health challenges.

Environmental hazards associated with release of emission from petroleum refineries have caused serious concerns for the host communities. The study focused on the assessment of the contribution of Nigerian refineries to the ambient air quality. Total emission of toluene, ethyl benzene and xylene (TEX) from Nigerian twenty-six (four existing and twenty-two proposed) refineries were estimated using emission factor approach, under no-control measure (worst case scenario) option. Results showed that the four existing refineries emit 2.90 × 10¹³ tons of toluene, 1.93 × 10¹³ tons ethyl benzene and 1.06 × 10¹³ tons per year while the twenty-two proposed refineries have the capacity of releasing annually 9.17 × 10¹³ tons of toluene, 6.69 × 10¹³ tons of ethyl benzene and .95 x 10¹³ tons of xylene. If operated at full capacity, the total estimated TEX emission from the existing refineries stood at 5.89 × 10¹³ tons/year while the proposed refineries have the potential of adding additional 2.01 × 10¹⁴ tons/year. These concentrations were considered as environmental menace that could have adverse health challenge of the residents of the host communities. Some technologically driven measures to control and subsequently reduce TEX emission from these refineries were suggested.