In today's world, the need for coal energy is constantly increasing as new technologies are discovered and foreign countries such as China experience their own industrial revolution. This recent increase in energy consumption has made China the number one consumer of coal, accounting for 25% of the entire world's coal use. Acid rain, harmful airborne pollutants, and possible climate shifts are all threats to the well-being of not only the human race, but all life on the planet. Despite increasingly strict air quality standards and innovations in coal-burning flue gas pollution control, pollutants naturally found in coal such as arsenic and selenium continue to enter the atmosphere.

Ab initio methods such as quadratic configuration and coupled cluster combined with the complete Pople basis set, 6-311++G(3df,3pd), were employed to calculate reaction thermochemistry and corresponding equilibrium constants for a series of reactions between arsenic, selenium, and various atmospheric gases at standard temperature and pressure. Theoretical kinetic investigations of formation reactions for the arsenic and selenium species found to be stable at atmospheric conditions were carried out as well. Reaction pathways in the troposphere involving these trace species from coal combustion flue gases have been predicted. Understanding the speciation and ultimate fate of these trace contaminants will aid in the design of more effective control strategies.