Exhaust gas, also known as exhaust emissions or tailpipe emissions, is the gas that is expelled from an automobile’s exhaust system. This gas is a combination of carbon dioxide, unburned hydrocarbons, nitrogen oxide, and more. These emissions are created during the process of combustion in which fuel combines with oxygen and releases energy. Exhaust gas does not just contain gases but can, unfortunately, also contain dangerous chemicals and particles that are harmful to both the environment and humans. Of course, it is important for auto manufacturers to take proper steps to reduce the number of pollutants released into the atmosphere from cars by creating more efficient engine designs and technologies that decrease exhaust gas emissions.