OFFICE OF AIR AMD RADIATION BPA420-B~08:r-OQ5 Dear Manufacturer or other Interested Party: Subject: Nitrogen Dioxide Limits From Retrofit Technologies This is to inform you that the US Environmental Protection Agency's (EPA's) National Clean Diesel Campaign (NCDC) is establishing a nitrogen dioxide (NOi) limit for diesel retrofit technologies verified under the NCDC's Retrofit Technology Verification Program. As you likely know, the California Air Resources Board (ARB) has established limits for increases in NOi emissions for diese! emission control strategies. In establishing an N€>2 limit for NCDC verified technologies, EPA intends to harmonize with ARB's limits, test procedures and requirements for technologies included on the NCDC's Verified Technologies List, It is appropriate to avoid potential increased NO2 levels as greater numbers of engines are retrofitted, although the EPA does not have an immediate pressing concern for NOi emissions from retrofit technologies. We believe that harmonizing with ARB's NC»2 limit is an appropriate action that will help limit NOa emissions, and enable retrofit technology manufacturers to produce one technology that can be marketed nationwide while meeting the same Nt>2 requirements. Effective January 1, 2009, the NCDC is implementing the limit for increases in NC>2 that will also be required by the ARB for retrofit technologies. This requirement limits the increase in NO? emissions associated with some types of retrofit technologies to levels no greater than 20 percent above baseline engine levels. To evaluate compliance with this requirement, we are adopting the ARB test procedures at Title 13 Chapter 14 Section 2706 of the California Code of Regulations. As a result, manufacturers must use the same procedures for any new EPA and ARB verifications. For existing EPA verified technologies, manufacturers must submit NC>2 data to EPA prior to November 1, 2008 or those technologies will be removed from the NCDC Verified Technologies List as of the effective date of this requirement. Data previously submitted and approved by ARB may also be submitted to EPA to demonstrate compliance with these limits. Manufacturers shall work with EPA prior to conducting any additional testing to demonstrate compliance with this limit. In the meantime, EPA intends to update the Verified Technology List to indicate which technologies have demonstrated compliance with this limit. ------- -2- If you have any questions regarding this matter, please contact Dennis Johnson of my staff at 202-343-9278 or by email at johnson.dennis@epa.gov. Sincerely, Lori Stewart, Acting Director Transportation and Regional Programs Division Office of Transportation and Air Quality ------- |