The California Air Resources Board may ease emission standards for model-year 2003 transport refrigeration units, set to take effect Dec. 31, 2010.

As it stands, model-year 2003 engines are required to meet the ultra-low emission TRU (ULETRU) in-use standard requirement, but the proposed amendment would require these engines to meet the low emission TRU (LETRU).

The Board is moving to change the compliance requirements because the retrofit technology needed to meet the ULETRU standards are not readily available in the marketplace, according to an advisory. LETRU emission standards can be achieved by installing a readily available Level 2 verified diesel emissions control system.

If the change is approved, these model-year engines would not have to comply with the ULETRU standard for seven years.

The Board will vote on the amendments in November, and they should go into effect spring of 2011.

Until these changes are adopted, CARB recommends that owners of model-year 2003 engines prepare to meet the LETRU standard by installing a Level 2 verified diesel emissions control system by Dec. 31. However, if Level 3 verified diesel emissions control systems become available sooner than expected, owners should install these devices. In this case, owners would be compliant with the ULETRU standards.

For more information, go to www.arb.ca.gov/diesel/tru.htm.