## 4 Discussion
### Mitigation Strategies
#### 4.2.7 What Can We Have in the Localized Treatment Stations for the Gaseous Emissions? Various potential GHG treatment methods have been described by different scholars. It is well known that condensation of water vapor transforms the vapor back into liquid water. Condensation is also an effective method of removal of some other volatile compounds. Volatile organic compounds are among the most common pollutants that are emitted from chemical process industries that deal with the manufacture and processing of chemicals such as solvents, liquid fuels, lubricants, degreasers, cleaners, and thinners [64]. The results of a model parametric study by some scholars [64] suggested that if there is a wide variation in the concentration of volatile organic compounds in the gaseous emissions, condensation followed by adsorption is an effective technique to control emissions. If VOC emission levels are high above 1%, condensation is found to be suitable, and if the VOC emissions are very low, adsorption is preferred for the removal of VOC. Another study [65] also noted that adsorption was effective if the concentration of VOCs is in parts per million levels, and the removal by cryogenic condensation is effective at a relatively higher concentration of VOC (>1%). With this information, a condensation section in one of the treatment plants should be beneficial in the localized treatment of some of the GHG emissions. Some researchers [66] described a method to remove sulfur oxides from flue gases. The proposed method includes the absorption of sulfur oxides in an aqueous alkali carbonate solution and the reduction and dissolution of the salts formed in water. The hydrogen sulfide that was obtained is processed into sulfur. The use of lime-coated sulfide pellets is a promising method for controlling sulfur oxide emission during the roasting of metal sulfides [67]. Unlike NO, which has low solubility, NO\({}_{2}\) is highly soluble in water [68]. Sulfur dioxide (SO\({}_{2}\)) is soluble in water (11 g/1 at 20 degrees C). Sulfur dioxide also dissolves in atmospheric moisture [69]. Some scholars [68] proposed a two-step process that is capable of removing NOx and SO\({}_{2}\) simultaneously. The proposal is made up of an ozoning chamber and an absorber that contains a reducing agent solution. The scholars reported that as exhaust gases pass through the ozoning chamber and absorber sequentially, a NOx removal efficiency of 95% was achieved and an SO\({}_{2}\) removal efficiency of 100% was achieved. Sodium sulfide was used as a reducing agent. The authors noted that H\({}_{2}\)S formation from sodium sulfide can be suppressed through a reagent (NaOH). This information indicates that some of the GHGs are soluble in water. Some of the GHGs can also be absorbed by other solutions. One of the GHG capture and storage methods described by IPCC 2005 is ocean storage [39]. While that may not be a popular approach, it also confirms that some of the GHGs of concern can be locally contained through dissolution or absorption in some liquids. A previous study [5] noted that while the US power plants' hourly reports have reliable data for CO\({}_{2}\) emissions, the hourly measurements for NOx and SO\({}_{2}\) remain unreliable in some regions. Accurate measurements of the quantity of emissions will be helpful in planning for the efficient capture and reprocessing of gaseous emissions. If using the water-based solution to capture SO\({}_{2}\) and NOx, knowledge of the rate of release of the gases and the quantity of the gases that can be dissolved by various amounts of solution will be helpful. Some scholars [70] reported that the reaction of carbon dioxide with an aqueous solution of sodium hydroxide could result in the formation of sodium bicarbonate (NaHCO\({}_{3}\)). An experiment in which a bench-scale unit of reactor systems was designed was able to capture 2 kg of CO\({}_{2}\) per day. While the absorption rate of CO\({}_{2}\) was more than 95%, the purity of the Sodium bicarbonate that was produced was more than 97%.