March 9, 1998

Dear Sir/Madam:

The staff of the Air Resources Board (ARB) would like to inform you of a public workshop to discuss the environmental impacts of motor vehicle combustion chamber deposits (CCDs) and the need to control CCDs.

At the workshop, a summary will be presented of our assessment of issues concerning CCDs. Over the past several months, ARB staff have researched available technical literature regarding CCDs and their effects on motor vehicle performance and emissions. Also, we met with representatives from the automobile manufacturers, gasoline additive manufacturers, and the oil industry to obtain an overall perspective on CCDs, the ability to control them, and to assess the potential for emission reductions based on CCD control.

The workshop will be held at the following:




General Services Bldg.
1325 J Street
Sacramento, California
Room 1946 (19th floor)
  March 24, 1998
9:30 a.m. to 12:30 p.m.

Enclosed is an agenda and a list of topics that will be discussed at the workshop. The ARB staff solicits comments regarding the need for CCD control. This workshop is intended to provide a forum for discussion, and presentations by individual companies are encouraged. To be included on the agenda, or to discuss any other questions relating to the workshop, please contact Jim M. Aguila, Air Resources Engineer, at (916) 327-1512.

The meeting facility is accessible to persons with disabilities. If accommodation is needed, please contact Ms. Jacqueline Wilson at (916) 327-1493 or TDD (916) 342-9531, or (800) 700-8326 for TDD calls outside the Sacramento area, by March 16, 1998.

Topics for Discussion

*   CCD Formation
- factors affecting CCDs
- current California CCD levels
*   Comparison of CCD Levels (Cleaner- burning gasoline vs. Conventional
- lower T90, aromatic HC
- lower additive treat rates
*   CCD/NOx Correlation
*   Current NOx benefit with Cleaner-burning gasoline
*   Need to preserve NOx benefit
- development of CCD no harm demonstration
     * performance test
     * fuel specification
*   Potential impact of CCD "no harm" requirement on approved gasoline certifications
*   Need for further CCD reductions
*   Need for further IVD reductions