The US Environmental Protection Agency (EPA) is responsible for implementing and enforcing federal regulations for pollutant emissions produced by on-highway and off-road engines.

The focus of the EPA is to reduce the six common pollutants: ozone, particulate matter, carbon monoxide, nitrogen oxides, sulfur dioxide, and lead. They do so by implementing a set of standards to reach increasingly stringent emissions levels in the United States.

This paper provides an overview of the three primary EPA regulations affecting generator set use in the United States