Santa Barbara County APCD

The Santa Barbara County Air Pollution Control District covers the county, including all eight incorporated cities. Its significance thresholds are in Article V, Section F of the Environmental Review Guidelines, which its Board adopted on October 19, 1995 and revised on November 16, 2000 and April 30, 2015; the 2015 revision included a greenhouse gas threshold. The district uses the thresholds when it is the lead agency. Elsewhere a city or the County applies thresholds it has adopted, and where it has none, the district recommends its own. Its CEQA Handbook, updated in October 2025, carries the method and prints numbers the Guidelines only point to.

Operational thresholds

Table 1 of the Handbook, Thresholds of Significance for Operational Criteria Pollutant Emissions:

The 240 and 80 lb/day figures are the offset triggers of the district's New Source Review rule as it read when the Guidelines were adopted in October 1995. CO has no daily operational number because the county attains the CO standards, and with background CO this low the Handbook no longer asks for CO hotspot studies.

A project's operation is less than significant when it passes all five tests: every source together stays under the total row; vehicle trips stay under the vehicle row; it neither creates nor worsens a violation of any state or federal ambient standard other than ozone; its cancer risk is below 10 excess cases per million and its acute and chronic hazard indices do not exceed 1.0; and it fits the county's most recent adopted federal and state clean air plans.

Mobile, area and stationary sources are summed for the total row; only vehicle exhaust goes against the vehicle row, and cranes, dozers and other off-road machines working on site belong in the total. Reports give reasonable worst case pounds per day and maximum tons per year, and annual metric tons of CO2e. The lead agency sets the emissions baseline, and the project's increment is compared with the thresholds. The estimate covers the whole facility's potential emissions, including existing and new equipment and activities under worst-case operating assumptions, with a separate calculation for each proposed operating scenario. The district recommends the latest CalEEMod.

Screening

Appendix A, the Mobile Source Emissions Screening Table, gives for common land uses the size at which vehicle trips reach about 22.5 lb/day of ROG or NOx, about ten percent under the 25 lb/day threshold. It was run in CalEEMod version 2022.1.1.29 for a 2025 operating year in Traffic Analysis Zone 3361, in the Santa Ynez Valley, whose trips are the region's longest. Some sizes: 240 single family houses, 425 apartments, 270,000 square feet of general office, 14,000 square feet of supermarket. A use the table lacks, mixed uses, district-permitted equipment or a larger project needs a CalEEMod run, and the table does not screen GHG.

Construction

The district has no quantitative CEQA threshold for construction. It asks that construction NOx, ROC, SOx, PM10, PM2.5 and GHG be calculated and disclosed, and CEQA still calls for a finding on their significance. A lead agency may choose 25 tons per year of any criteria pollutant except CO as its yardstick. That number comes from Rule 202.D.16, which makes a permitted stationary source offset construction equipment emissions above 25 tons of a pollutant in 12 months. It is not a district CEQA threshold, and a lead agency that uses it presents it as its own and explains why.

Because the county does not attain the state PM10 standard, every discretionary project that moves earth gets the standard dust controls, whatever its size, from the district's Attachment A: Fugitive Dust Control Measures; Attachment B: Construction Diesel Particulate and NOx Emission Measures covers equipment exhaust. The Handbook recommends a quantitative construction health risk assessment when work runs longer than six months near sensitive receptors and the project has not committed both to Tier 4 Final off-road engines above 50 horsepower and to no diesel or gasoline generators.

Health risk

Table 2 sets cancer risk at 10 or more excess cases in a million and non-cancer risk, chronic and acute, at a Hazard Index above 1.0. A refined assessment follows the district's Modeling Guidelines for Health Risk Assessments (APCD-15i), runs in HARP 2, and models operating vehicle emissions out to 1,000 feet beyond the property line. A project with a significant risk cannot get a district permit, so the district asks lead agencies to settle risk during CEQA. It also advises keeping homes, schools, child care, senior housing and medical uses 500 feet or more from Highway 101.

Greenhouse gases

Article V, Section F.2 of the Guidelines, repeated as Table 3 of the Handbook, covers stationary source projects, meaning those that need a district permit to operate. The 2015 Guidelines listed three alternatives for finding a stationary source project's GHG impact less than significant:

• its annual emissions are under 10,000 metric tons CO2e;
• it meets an approved GHG reduction plan or mitigation program, as a source in the state's Cap-and-Trade program does;
• its emissions are 15.3 percent below business as usual, in line with the AB 32 Scoping Plan (Table 3 prints 15%).

The 2025 Handbook adds that later court rulings, and the test's focus on 2020, leave the business as usual option without support, and advises case by case decisions, with legal counsel, for a stationary project above 10,000 metric tons CO2e per year outside an approved plan or program.

For land use development the district has no GHG threshold. The Handbook says the stationary source levels were not designed for homes or commercial buildings and that the lead agency settles GHG significance under its own guidelines; it notes that the County of Santa Barbara uses a GHG threshold it adopted itself when it issues land use permits. The district still wants GHG mitigated as far as reasonably possible, significant or not, and prefers reductions on site first, then in Santa Barbara County, then farther away.

Odor, plan consistency and larger sources

Odor has no number; Rule 303 governs nuisance, and an Odor Abatement Plan may be required. For Ozone Plan consistency, a residential project should support the plan and follow its land use and transportation control measures, and a commercial or industrial stationary source is generally consistent if it meets district rules. A project over the long-term thresholds, or inconsistent with the Ozone Plan, is cumulatively significant. Where permitted stationary sources could reach the Table 4 Air Quality Impact Analysis Thresholds (for example PM10 80, PM2.5 55, CO 500 and NOx 120 lb/day), the project models its impact under Rule 805, counting mobile and dust sources for CEQA.

What this means for a report

First find out whether the city or County has adopted thresholds. If not, operations are compared with the district's total and vehicle rows and the ambient, health risk and plan tests, and a permitted stationary source also takes the GHG test. Construction emissions are calculated and disclosed, and any tonnage applied to them is the lead agency's. A land use project's GHG finding rests on the lead agency's threshold. Under the Guidelines, a project over a threshold generally needs an EIR, unless the applicant accepts changes that bring the effect under significance, when a Mitigated Negative Declaration may do. The thresholds date from 1995 and were last revised in 2015.

Where the thresholds are published

Santa Barbara County Air Pollution Control District, Environmental Review Guidelines for the Santa Barbara County Air Pollution Control District: Guidelines for the Implementation of the California Environmental Quality Act of 1970, as amended; adopted October 19, 1995, revised November 16, 2000 and April 30, 2015 (Article V, Section F). CEQA Handbook: A Guide for the Preparation of Air Quality Sections in Environmental Documents, updated October 2025 (Sections 1, 4.1.3, 4.3, 5.1 through 5.10, 6.1 and 6.2.7; Tables 1 through 4; Appendix A Mobile Source Emissions Screening Table). District web page Environmental Review Resources and Notices, which shows no modified date.