Most people are familiar with automobile air emissions. Perhaps one day there will only be electric cars and no car air emissions. But there are many on other engines in use by commercial and industrial operations that may cause air emissions. In general these are called reciprocating internal combustion engines (RICE).

On February 17, 2010, the Environmental Protection Agency (EPA) issued a final rule that will further reduce emissions of toxic air pollutants from existing diesel powered stationary reciprocating internal combustion engines.