Abstract: A method and a system for treating an internal combustion engine exhaust gas using a hydrocarbons as fuel. The internal combustion engine exhaust gas contains particulates and toxic substances. Such particulates and toxic substances being liquid and gaseous hydrocarbons, carbon monoxide, and Nox. The system uses carbon dioxide to interact with the exhaust gas. The carbon dioxide is stored within a container at its triple state. The carbon dioxide and the exhaust gas are conducted through an emission exchanger. The exhaust gas is scrubbed or cleaned by the carbon dioxide and the hydrocarbons, carbon monoxide, Nox, and particulate emissions are carried away by a carbon dioxide gas stream. The cleaned exhaust gas can be discharged into the atmosphere. The carbon dioxide gas stream can be cleaned by passing the same through separator components which remove the pollutants therefrom.