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State Air Quality Agencies Urge EPA to Lower NOx Standard for Heavy Duty Trucks


Air quality officials from Arizona, California, Connecticut, Delaware, New Hampshire, Nevada, New York, Ohio, and Washington State submitted a formal petition to EPA Administrator Gina McCarthy urging the agency to conduct a rulemaking to impose a tighter nitrogen oxide (NOx) standard for heavy duty trucks.  The 38-page petition makes the case that California and other areas of the country cannot attain federal air quality standards for ozone levels without more demanding federal emission rules for on-road trucks.  The petition points out that on-road trucks produce a significant amount of the NOx emissions in many areas of the country and are the largest source in key areas.

A major theme of the petition is that federal controls are necessary because the transient nature of trucks means that state officials cannot control the emissions of trucks that are registered in other states but nevertheless travel through them. The petition points out that technology exists to lower emissions from heavy duty trucks and includes information on the availability of the 8.9 liter low-NOx natural gas engine produced by Cummins Westport and supported by the SCAQMD, CEC and Southern California Gas Company. The petition also highlights expected developments concerning future low-NOx natural gas engines.  Also evident in the petition is the expectation that diesel engines also will be able to meet the more demanding standards as early as 2022. The petition indicates that establishing a nationwide standard of 0.02 g/bhp-hr will maximize the use of natural gas technology as well as cleaner diesel technology.

Another major theme of the petition is the need to establish these standards so that they take effect commensurate with EPA’s Phase 2 greenhouse gas regulations for heavy duty vehicles.  Citing information submitted by the Manufacturers of Emission Control Association (MECA), the petition argues that it is more cost-effective if changes to engines are made simultaneously to meet the new standards for GHG emissions and NOx emissions. The timing of the petition is telling, having been filed the same day that the Office of Management and Budget received a copy of the draft final rule for the Phase 2 heavy duty GHG standards. Many environmental organizations had urged EPA to impose lower-NOx limits as part of that rule. Knowing that the rules will not propose any changes to NOx levels likely led to the filing of the petition.

The petition also urges EPA to amend incentives provided under the Diesel Emission Reduction Act to specifically encourage 0.02 g/bhp-hr NOx engines as soon as possible and to also allow operators to keep their old trucks so long as they are only operated in areas outside of non-attainment areas. The DERA program typically requires operators to scrap old trucks, so letting owners keep the trucks is a useful incentive to encourage increased interest.