CO₂ Measurement in CARB Source Testing

As part of our CARB-compliant source testing services, REM includes precise measurement of carbon dioxide (CO₂) to support accurate emissions characterization and regulatory reporting.

CO₂ is a critical parameter in air emissions testing. It is used not only to quantify greenhouse gas output, but also as a reference gas for calculating combustion efficiency, correcting pollutant concentrations to standard conditions, and performing F-factor–based emission rate calculations required by CARB and EPA methodologies.

How REM Measures CO₂

REM utilizes U.S. EPA–approved methodologies, primarily EPA Method 3A, to continuously measure CO₂ concentrations in exhaust gas streams. This method is widely accepted by CARB and is designed for high accuracy and reliability under field conditions.

Our process includes:

• Continuous Emission Monitoring (CEM):
  We deploy advanced gas analyzers that use non-dispersive infrared (NDIR) technology to detect and quantify CO₂ concentrations in real time. NDIR is the industry standard for CO₂ measurement due to its selectivity, stability, and precision.

• Heated Sample Extraction System:
  Exhaust gas is extracted through a heated probe and sample line to prevent condensation and maintain the integrity of the gas composition. This ensures accurate readings even in high-moisture or variable-temperature stacks.

• Moisture Management:
  Depending on test requirements, measurements may be reported on a dry or wet basis. REM conditions the sample accordingly, removing moisture when necessary to align with specific CARB reporting protocols.

• Calibration and Quality Assurance:
  All CO₂ analyzers are calibrated before, during, and after testing using certified calibration gases traceable to NIST standards. We perform zero and span checks to verify instrument accuracy and drift, ensuring defensible data.

• Data Acquisition and Averaging:
  CO₂ concentrations are recorded continuously and averaged over defined test runs in accordance with CARB and EPA guidelines. This data is integrated with flow rate and other parameters to calculate emission rates.

Why CO₂ Measurement Matters

Accurate CO₂ measurement is essential for:

• Regulatory Compliance: Meeting CARB and EPA reporting requirements

• Emission Calculations: Supporting F-factor and heat input calculations

• Combustion Efficiency Analysis: Evaluating system performance and optimization opportunities

• Greenhouse Gas Reporting: Quantifying CO₂ as a primary GHG emission

REM’s Advantage

REM’s testing approach is built on rigorous adherence to regulatory methods, combined with field-proven expertise. Our team ensures that every CO₂ measurement is:

• Method-compliant (EPA/CARB approved)

• Fully calibrated and quality-assured

• Representative of actual operating conditions

• Documented for audit-ready reporting