The Clean Air Act Amendments of 1990 (CAAA) address 189 hazardous air pollutants (HAPs) deemed harmful to human health and the environment and found that mercury and its compounds are one of the highest priority pollutants to investigate. The CAAA has requested that the U.S. Environmental Protection Agency (EPA) conduct a study of mercury emissions, including those from electric utilities' steam generating units. In 1997, the EPA released the Mercury Study Report to Congress that analyzed mercury emissions from power plants and investigated control technologies. In 1998, the EPA released the Utility Air Toxics Study which also showed mercury as a top priority pollutant due to its potential for multi-pathway exposure and its ability to bioaccumulate and persist in the environment as methylmercury. [1, 2]The control of mercury in combustion exhaust gases is highly dependent on speciation. Oxidized mercury is removed relatively easily by particulate control equipment and wet scrubbers used to control sulfur dioxide. However, elemental mercury is highly volatile and has very low water solubility which allows it to escape through most pollution control equipment. The objective of this project is to understand the importance and contribution of gas-phase carbon constituents in mercury oxidation reactions. The project involves experimental efforts. The objective is to determine the relevant experimental parameters in homogeneous oxidation reactions; effect of each of these parameters on mercury oxidation for various concentrations and temperatures. The objective of this project was to test the performance of bromine and chlorine (Cl2) on the homogeneous oxidation of mercury in the presence of common flue gas components such as nitric oxide... middle of paper... constituents or same before it can oxidize the mercury at the required temperature. A fundamental understanding of mercury waste gas chemistry is needed to develop effective control technologies for mercury. Because the reactions of atomic and molecular chlorine with other flue gas constituents determine the concentration of reactive chlorine species remaining in the cooled gas, the effects of specific gas constituents on chloromercury have been extensively studied. Experimental data indicate a negative effect of chlorination of mercury with SO2 and NO in the presence of H2O [13]. Recent experimental data from the EERC indicate that bromine species have high potential in mercury control applications [12]. In the proposed study the emphasis is on the homogeneous reactions of mercury in flue gases with Br2 and Cl2 in the presence of other flue gas constituents.