The Environmental Protection Agency (EPA) is planning to conduct a field pilot program to collect and analyze data related to the environmental effects from nitrogen oxides (NOx) and sulfur oxides (SOx). After review, EPA is also proposing secondary air quality standards to protect the environment from both NOx and SOx, while working to reduce emissions.

Nitrogen oxides are emitted from an array of sources, including vehicles, power plants, off-road equipment and agricultural sources. Sulfur oxides are emitted from fossil fuel combustion by power plants, large industries, mobile sources, and from some industrial processes.

EPA has worked to develop a multi-pollutant standard that would seek to protect vulnerable ecosystems, including streams and lakes. The field pilot program is intended to help ensure any updated standard is effective.

In the meantime, EPA is proposing to set an additional secondary standard for each pollutant. These standards reduce the amount of NOx and SOx in the air and the harmful effects that they have on sensitive lakes and streams. EPA is also proposing to retain the existing secondary standards for each pollutant.

EPA will accept comments for 60 days after the proposed standards are published in the form of a proposed rule in the Federal Register. A final rule will be issued by March 2012.

Read more about the rules and see a list of frequently asked questions at: