New transport refrigeration unit requirements are now in effect in California, according to an email reminder from the California Air Resources Board.
Deadline Looms for New CARB Transport Refrigeration Unit Emissions Rules
Refrigerant, particulate emissions get stricter for transport refrigeration units in California soon.

CARB regulations affect transport refrigeration units based outside the state, too.
Source: CARB
New regulatory requirements as a result of the 2022 amendments to the Airborne Toxic Control Measure for In-Use Diesel-Fueled Transport Refrigeration Units (TRU) and TRU Generator Sets, and Facilities Where TRUs Operate (2022 Amendments) became effective Oct. 1, 2022.
CARB adopted the TRU ATCM in 2004, and amended it in 2010 and 2011, to reduce PM (particulate matter) emissions from diesel-powered TRUs. On Feb. 24 of this year, CARB adopted amendments to the TRU ATCM (2022 Amendments) to achieve additional emission reductions from diesel-powered TRUs.
Beginning Dec. 31, 2022:
Newly manufactured truck TRUs, trailer TRUs, and domestic shipping container TRUs must use refrigerant with a global warming potential less than or equal to 2,200, or no refrigerant at all.
Model year 2023 and newer trailer TRU, domestic shipping container TRU, railcar TRU, and TRU generator set engines must meet a PM emission standard of 0.02 grams per brake horsepower-hour or lower.
Vehicle owners of TRU-equipped trucks or tractor-trailers equipped with a TRU shall ensure the TRU is compliant. If requested, drivers shall allow CARB personnel to conduct a visual inspection of their TRU.
Beginning Dec. 31, 2023:
Owners of refrigerated warehouses or distribution centers with a building size of 20,000 square feet or greater, grocery stores with a building size of 15,000 square feet or greater, seaport facilities, and intermodal railyards with TRU activity (applicable facilities) must register the facility with CARB, pay fees every three years, and report all TRUs that operate at their facility to CARB quarterly, or alternatively ensure that only compliant TRUs operate at their facility (i.e., those with a valid CARB compliance label or showing as compliant on CARB’s website).
TRU owners shall report all TRUs (including out-of-state based) that operate in California to CARB.
TRU owners shall pay TRU operating fees and affix CARB compliance labels to their TRU every three years, for each TRU operated in California.
TRU owners shall turn over at least 15% of their truck TRU fleet (defined as truck TRUs operating in California) to zero-emission technology each year (for seven years). All truck TRUs operating in California shall be zero-emission by Dec. 31, 2029

CARB's TRU rules are designed to slash particulate emissions.
Source: CARB
CARB staff developed a regulatory advisory, fact sheet, and Frequently Asked Questions document on the regulatory requirements:
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