Air Quality Update

September 1, 2021 – SCAQMD

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Phase-Out Schedule

The California Air Resources Board (CARB) Portable Engine Airborne Toxic Control Measure (ATCM) mandates reduction of emissions from diesel portable engines in California, whether permitted with the South Coast Air Quality Management District (SCAQMD) or registered with the CARB Portable Equipment Registration Program (PERP). Small fleets have up to 750 cumulative horsepower (HP) under common ownership in California and must follow the tier phase-out schedule for small fleets (see Table 1). Large fleets have over 750 cumulative HP and must follow the large fleet tier phase-out schedule (see Table 1) if they did not opt into the fleet average option back in June 2019.

Note that Tier 4 engines (interim or final) do not phase-out, nor do engines with Level 3 Verified Diesel Emission Control Strategy (VDECS) [85% reduction of particulate matter (PM) or to 0.01 gram per brake-horsepower-hour (g/bhp-hr) of PM].

Low-use and emergency-use engines are exempt from the phase-out schedule. The switch to low-use or emergency-use must be made by:

  • For Tier 1 and Tier 2, at least 6 months before phase-out dates in Table 1; and
  • For Tier 3, in January at least 12 months before phase-out dates in Table 1.

Low-use engines are limited to 200 hours per calendar year, and hour-
meter reports are due by March 1st

Engines certified as “flexibility” (flex)1 will phase-out on December 31st of the year 17 years after the engine build date.

Table 1: January 1st Phase-Out Dates

Tier Engines 50-750 HP Engines Over
750 HP
Large Fleet Small Fleet
1 2020 2020 2022
2 2022 2023 2025*
3 2025 2027* N/A
4 N/A N/A N/A


Portable Engine Sales

Table 2: January 1st Sale Prohibition Dates


Tier Engines 50‑750 HP Engines Over 750 HP
1 2020 2022
2 2023 2025*
3 2027* N/A
4 N/A N/A

Portable engines cannot be sold in California after the January 1st dates shown in Table 2, corresponding to the tier. Change of ownership applications, however, are due at least 6 months prior to the sale prohibition dates.

*Engines built on or after 1/1/2009 have an additional 2 years.

1See Code of Federal Regulations (CFR) Title 40 Part 1039.625:

Air Quality Tip

California is continuing to develop zero-emission vehicle requirements for on-road and off-road vehicles. If you are purchasing diesel, gas, or propane vehicles, you may want to evaluate electric options. In some cases, there may be funding available from CARB or your local air district. Electric fueling stations that qualify can generate Low Carbon Fuel Standard (LCFS) credits, which can fund additional electrification.

Upcoming Due Dates for 2021/2022*

*Due dates listed are statutory dates; sometimes dates are extended when on a weekend/holiday. 

  • CARB LCFS Q2 Fuel Report……… 9/30/21
  • SCAQMD 1110.2 Quarterly……… 10/15/21
  • RECLAIM Quarterly (Cyc. 1 & 2). 10/30/21
  • CARB GHG Cap-and-Trade
    Annual Compliance Surrender……. 11/1/21
  • CARB LCFS Q3 Fuel Report……. 12/31/21
  • CARB Off-Road Diesel Compliance for All Fleets, by Fleet Average or BACT 1/1/22
  • CARB On-Road HDDVs That Must Be
    Repowered, Retired, or Low-Use….. 1/1/22
  • GVWR > 26,000 lbs, EMY 2006 or Older
  • SCAQMD 1110.2 Quarterly……….. 1/15/22
  • RECLAIM Quarterly (Cycle 2)…… 1/30/22
    Reporting for Flexibility Options… 1/31/22
  • Title V – 500-SAM……………………. 2/28/22
  • RECLAIM APEP (Cycle 1)………….. 3/1/22
  • Title V – 500-ACC……………………… 3/1/22
    (Except RECLAIM Cycle 2………. 8/29/21)
  • CARB Off-Road DOORS
    Reporting for All Fleets……………….. 3/1/22
  • CARB PERP Reporting: Usage Reports for Equipment Units or Low-Use 3/1/22
  • CARB Refrigerant Reporting for
    Medium/Large Systems (≥ 200 lbs). 3/1/22
  • CARB GHG Semiconductor Report. 3/1/22
  • Title V – Application for Permit Renewal – Due 180 Days Prior to Permit Expiration

Upcoming Online EH&S Training Offered by Yorke Engineering

Southern California Air Quality Regulations, Permitting, and Compliance Seminar: November 2, 4, 9, 11, 2021 (Half-Days)
Class Info at:


Rule 2305 was adopted by the Governing Board on May 7, 2021, and applies to owners and operators of warehouses located in the SCAQMD. This new rule has fast-approaching reporting requirements for both owners and operators, including already requiring some warehouse operators to be counting truck trips. Rule 2305 defines a warehouse as a building that stores cargo, goods, or products on a short- or long-term basis for later distribution to businesses and/or retail customers. There are separate requirements that apply to owners and to operators of warehouses.


Owners of warehouses greater than or equal to 100,000 square feet (ft2) of indoor floor space in a single building were required to submit a one-time Warehouse Owner Notification (WON) report by September 1, 2021 (or within 30 days of applicability or changes in tenants/sizes). The report required information about the size of the warehouse, tenants’ names, tenants’ contact information, and information on space used for warehousing activities.


Operators in a building with a cu-mulative (across all tenants) of less than 100,000 ft2 of warehousing activities (i.e., the warehouse space not including offices, retail areas, manufacturing areas, etc. that are separated from the warehousing ac-tivities by walls) are exempt from the rule.

Operators in buildings with cumula-tive warehousing activities of at least 100,000 ft2 are required to submit an Initial Site Information Report (ISIR) due by July 1st of ei-ther 2022, 2023, or 2024, depending on the total warehouse size category shown in Table 3.

Table 3: Summary of Operator Warehouse Size and Initial Dates

Total Warehouse Size (ft2) First Year of Truck Trip Counting ISIR Due Initial WAIRE
Compliance Period
First Annual WAIRE
Report Due
250,000 or Larger 7/1/2021 – 6/30/2022 7/1/2022 1/1/2022 – 12/31/2022 1/31/2023
150,000 – 249,999 6/1/2022 – 5/31/2023 7/1/2023 1/1/2023 – 12/31/2023 1/31/2024
100,000 – 149,999 6/1/2023 – 5/31/2024 7/1/2024 1/1/2024 – 12/31/2024 1/31/2025


Operators with their own warehousing activities less than 50,000 ft2 only need to provide contact information and size information in the ISIR and have no future annual reports or obligations.

Operators with warehousing activities of at least 50,000 ft2 are required to:

  • Also include in the ISIR:
    • Truck trip data for the previous 12 months and anticipated truck trips for the next compliance period, each tallied in two weight categories: Class 2B through 7 (straight trucks) and Class 8 (tractors);
    • Vehicle miles traveled for the previous 12 months of their operated vehicles by weight class and fuel type, as well as typical time spent parked at the warehouse and indication of which are owned versus leased;
    • Hours for the previous 12 months of their yard tractors, as well as fuel type, size, quantity, and whether registered with the Department of Motor Vehicles; and
    • Information about any existing alternate fueling or zero-emission infrastructure and chargers; and
  • Calculate their annual WAIRE Points Compliance Obligation (WPCO), earn WAIRE Points, and submit Annual WAIRE Reports.

The WPCO, which is the quantity of WAIRE Points required to comply each year, is calculated from truck trips for each weight category (Classes 2b through 7 and Class 8). Warehouse operators are required to meet their WPCO by earning WAIRE Points through actions and investments completed during the compliance period (calendar year), earned through either the WAIRE menu, a custom WAIRE plan, and/or mitigation fees of $1,000 per point.

Annual WAIRE Reports are due January 31st following each compliance period and must include final truck trip counts, updated WPCO calculations, information on the actions that generated WAIRE Points, and mitigation fees for any remaining WAIRE Points.

Warehouse operators who have a WPCO of less than 10 in any compliance period are exempt from the requirement to earn WAIRE Points, but must document the WPCO in an Annual WAIRE Report.

Note that truck trip tracking must be representative and verifiable, which can include guard shack logbooks, surveillance cameras, electronic telematics (GPS), and/or driveway sensors. Rule 2305 records are required to be maintained for at least 7 years. For more info, visit the WAIRE Program homepage at:

Main Office:

31726 Rancho Viejo Rd. Suite 218
San Juan Capistrano, CA 92675

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