The Bay Area Air District (BAAD) is considering developing a rule to reduce air emissions and health impacts to the public from indirect sources, specifically targeting warehouses and distribution centers. BAAD discusses the benefits of regulating indirect emissions during a stationary source committee meeting on March 12, 2025, including any challenges that may arise during the development and implementation process. BAAD is reviewing and considering similar rules from other air districts’ indirect source rules (ISRs) such as San Joaquin Valley Air Pollution Control District (SJVAPCD) (similar rule currently effective), San Diego Air Pollution Control District (SDAPCD) (similar rule under development), and South Coast Air Quality Management District (SCAQMD) (similar rule currently effective).
What are Indirect Sources and What Sources will be Affected?
Indirect sources are facilities that attract mobile sources such as marine ports, airports, railroads, and are also referred to as “magnet sources”. An example pathway would be emissions generated from unloading goods at marine ports and moved by heavy duty trucks from warehouses to retailers and consumer houses. Although various sources generate indirect emissions when goods are being moved from production to consumers, the ISR will focus on emissions generated from trucks associated with warehouses. It is likely there will be a minimum square footage threshold similar to SCAQMD’s rule.
There are approximately 16,000 warehouses in the Bay Area with various square footage. Approximately 45% of the warehouses are located in Overburdened Communities (OBC). In addition, roughly 30% of the OBC communities are in an Assembly Bill (AB 617) communities. Due to a steady increase in goods that are being delivered to consumers and the location of the warehouses, BAAD is proposing to move forward with the development of a similar warehouse ISR to reduce emissions of nitrogen oxides (NOx), particulate matter (PM), diesel PM (DPM).
CARB Regulations Limiting Truck Emissions
In addition, the Advanced Clean Fleets (ACF) waiver request submitted to the EPA was withdrawn by CARB on January 13, 2025. As a result, California Air Resources Board (CARB) is not currently enforcing the ACF rule, which would have affected emissions from private and federal fleets. However, Advanced Clean Trucks regulation is still in effect and there will be emissions benefits from the supply side. Due to uncertainties with EPA’s waiver process, BAAD did not include the benefits from the ACF and wants to implement ISR to fill the gap that would have been otherwise filled by the ACF.
ISR in Other Air Districts
The following air districts have developed or evaluated an ISR:
- SJVAPCD has developed and implemented Rule 9510 since 2005 to regulate indirect emissions. The rule applies to various developments over a certain size which require approval from a public agency, which includes warehouses.
- SDAPCD is currently evaluating the possibility of implementing an ISR to regulate warehouse and port operations, but has not yet moved forward with rulemaking.
- SCAQMD has implemented a complex regulation referred to as the Warehouse Actions and Investments to Reduce Emissions (WAIRE Program) via Rule 2305. The regulation applies to warehouses greater than 100,000 square feet and requires annual reporting. SCAQMD’s WAIRE Program provides the following compliance options to facilities affected by this rule:
- Warehouse operators are required to earn WAIRE points by either mitigating emissions or paying an annual mitigation fee
- The requirements are based on truck trips, warehouse size, and class of vehicles
BAAD will likely consider developing a rule similar to SCAQMD and providing various compliance options. Trinity is following this development closely and will update this article once the Air District releases additional information.
Benefits of an ISR
BAAD expects that the ISR will result in NOX, PM, and DPM reductions. Based on a screening assessment, BAAD anticipates NOX emission reductions will be realized in an amount of approximately 250 – 300 tons per year once fully implemented. This will help in attainment of ozone and fine PM National Ambient Air Quality Standards. The PM reductions will be relatively low compared to the PM reductions from other BAAD rules (up to 1.3 tons per year of PM reduction). PM reductions will, however, result in the reduction of DPM, a potent carcinogen. This screening assessment only evaluated regional impacts. BAAD anticipates that localized PM impacts may be significant for residences living close to indirect sources. BAAD will further evaluate localized PM impacts during the rulemaking process.
Potential Implications for Facilities
If you operate or own a warehouse or distribution center, you will be affected by this rule. Trinity recommends that facilities that operate “larger” warehouses (BAAD’s square footage threshold is to be determined) or within an OBC should follow the development of this rule closely. Companies providing fleets will be indirectly affected by this rule as they will be encouraged to use low or zero emission vehicles to meet potential compliance obligations. Warehouse and distribution center operators/owners should consider using low emission vehicles in anticipation of the development of this rule. Similar to SCAQMD, BAAD will likely provide various compliance options that subject facilities can choose to comply with (e.g., mitigation fee payments). In addition, Trinity expects that BAAD will require initial and annual reporting, similar to SCAQMD’s WAIRE Rule. BAAD expects the rule development process will take approximately 3 years.
Interested parties can review the presentation slides from the stationary source committee meeting on BAAQMD’s website. If you would like to discuss the consideration of an ISR and how it may impact your facility, please contact Trinity’s Oakland office or call 510.285.6351.
