The Environmental Protection Agency (EPA) is preparing a rule that would set new standards to reduce NOx emissions from heavy-duty truck engines beginning in 2024. The agency last tightened its NOx standards for truck engines in 2010 to 0.2 gram per brake horsepower-hour.
The California Air Rescue Board is pushing for a lower NOx standard, as low as .02, so they can meet the federal ambient air quality standards for the ozone. That would be a 90% reduction in NOx emissions.
What is NOx? Nitrogen Oxides. NOx pollutes air with its chemical compounds. NOx represents a family of 7 compounds. The EPA regulates nitrogen dioxide, NO2, as a surrogate for this family of compounds because it’s the most prevalent form of NOx in the atmosphere and is generated by human activity.