The Green research group focuses on the central problem of reactive chemical engineering: quantitatively predicting the time evolution of chemical mixtures. Accurate chemical kinetic models are extremely powerful and valuable, since they allow predictions about the impact of modifying a system; already many significant public policy and business decisions are made on the basis of kinetic model predictions. For example, the Montreal Protocol, which imposed a worldwide ban on certain halocarbons, was based on a kinetic model of the ozone layer. We are developing this simulation technology to solve practical problems related to the atmospheric chemistry of organic pollutants, the conversion of natural gas to liquid fuels, the oxidation of organics in the gas and liquid phase, the removal of sulfur contaminants from gasoline, and the formation of carcinogenic pollutants in combustion.