Certificate #01LA0921
SCAQMD LAP-Approved Test Methods
Nine method categories approved under South Coast AQMD's Laboratory Approval Program, current through December 31, 2026 — and verifiable against the District's published list.
Laboratory Approval Program
Approval Is Granted One Method at a Time
South Coast AQMD approves source testing firms one method at a time. Approval means the district has evaluated the firm’s personnel, equipment, procedures, documentation, quality assurance and audit performance against its own criteria — and several SCAQMD rules require testing be performed by an approved lab before results will be accepted.
Accurate Environmental Services holds SCAQMD Laboratory Approval Program certificate #01LA0921, covering the nine method categories below, current through December 31, 2026. Every one can be verified against SCAQMD’s published list of approved laboratories.
Certificate Scope
What #01LA0921 Covers
The full approval scope as it appears on the District’s Laboratory Approval Program roster.
Traverse points, velocity and flow, molecular weight, moisture
CO, CO₂, NOx, O₂ and SO₂ by continuous analyzer
Sampling & Analysis — wet impingement particulate
Sampling & Analysis — heated probe and filter
Sampling & Analysis — in-stack filter
Sampling & Analysis — sulfur oxides and sulfuric acid mist
Sampling only — volatile organic compounds
Sampling only — lower-concentration VOC streams
Protocol Testing — water heater and small boiler certification
Section 1 · Continuous Gas Analysis
Method 100.1
Approved for CO, CO₂, NOx, O₂ and SO₂
Method 100.1 is instrumental analysis of gaseous emissions using continuous analyzers. It’s the reference method behind CEMS certification and RATA testing, and it’s the method underneath most of the compliance work we do.
Our approval covers five analytes, including sulfur dioxide. That matters more than it sounds like it should. Not every approved firm carries SO₂ under 100.1 — one nearby competitor’s approval covers CO, CO₂, NOx and O₂ only. If your permit requires SO₂ by Method 100.1, confirm your tester is approved for it before the protocol goes in. Finding out afterward means retesting.
If you operate CEMS, this is the approval that governs your annual RATA. More on that on our CEMS and RATA testing page.
Section 2 · Particulate Matter
Methods 5.1, 5.2 and 5.3
SCAQMD maintains three separate particulate methods. They are not interchangeable — each collects particulate differently, and which one applies depends on your gas stream and your permit.
We are approved for Sampling & Analysis on all three.
Method 5.2 — Heated Probe and Filter
The method most source tests call for, and the majority of the particulate work we perform. Filterable particulate is collected on a heated glass fibre filter; condensables and anything passing the filter are caught in the impingers behind it. Held at 248°F ±25°F, it satisfies New Source Performance Standards testing. For NSPS only the front half counts; for District rules, both halves do.
Method 5.1 — Wet Impingement Train
Used less often, but required in specific circumstances. Particulate is collected in impingers of deionized water and on an unheated backup filter, held in an ice bath near 60°F. Total particulate mass sums the impinger, probe and filter catch after combined water is removed, plus extractable organic matter. Not used for NSPS compliance.
Method 5.3 — In-Stack Filter
The filter sits inside the stack rather than outside it, capturing particulate at stack temperature before any cooling occurs. Condensables and material passing the filter are collected in chilled impingers.
Permits rarely call for 5.3 — which is exactly why most firms let the approval lapse rather than maintain the equipment, the trained personnel and the annual audit it requires. Only three laboratories on SCAQMD’s approved list still hold Method 5.3. We’re one of them.
We keep it because approval scope is capability, and the test you can’t run is the one your client needs.
Section 3 · Sulfur Compounds
Method 6.1
Sampling & Analysis
Determination of sulfur oxides and sulfuric acid mist. Required as a companion measurement under Method 5.2 whenever the probe and filter run above 200°F and sulfuric acid exceeds 10% of the applicable rule standard — a pairing that catches facilities out when it isn’t planned for in the protocol.
Section 4 · Stack Conditions and Flow
Methods 1, 2, 3 and 4
The foundation under every source test.
Method 1 establishes where to sample — how many traverse points and where they sit across the duct cross-section. Method 2 measures gas velocity and volumetric flow rate using an S-type pitot tube. Method 3 determines the dry molecular weight of the gas. Method 4 determines moisture content.
These four run underneath everything else. Get them wrong and every emission rate calculated downstream is wrong with them.
Section 5 · Volatile Organic Compounds
Methods 25.1 and 25.3
Sampling
We are approved for the sampling side of both methods, with 25.3 applied to lower-concentration streams. Laboratory analysis is performed by approved analytical laboratories.
We state this plainly because the distinction matters on a protocol. A firm approved only for sampling shouldn’t present itself as performing the analysis.
Section 6 · Equipment Certification
Rule 1121 / Rule 1146.2
Protocol Testing
Certification testing of natural gas-fired water heaters and small boilers against SCAQMD’s NOx limits. Manufacturers and distributors bringing equipment into the South Coast Air Basin need this protocol testing to demonstrate compliance.
Verify It
Check the Roster Before You Hire Us
Every approval above appears on SCAQMD’s public Laboratory Approval Program roster under certificate 01LA0921. You’re welcome to verify it before you hire us — we’d rather you did.
If you’re unsure which method your permit requires, send us the permit. We’ll tell you what applies, and we’ll tell you honestly if it’s something we’re not approved for.
Send Us the Permit
We’ll tell you which methods apply, which of them we’re approved for, and what the protocol needs to say.