Rule 1147 in California 2026: Latest Updates, Pros, Cons & How EES Helps Industries
Rule 1147 — NOx Reductions from Miscellaneous Sources is an important South Coast AQMD regulation for certain fuel-fired combustion equipment in Southern California. It is designed to reduce nitrogen oxide (NOx) emissions while limiting carbon monoxide (CO) from permitted gaseous- and liquid-fuel-fired equipment that is not covered by another applicable Regulation XI rule.
Important: Rule 1147 is not a statewide California rule. It applies within the South Coast AQMD jurisdiction to equipment meeting the rule’s applicability requirements. Other California air districts have their own rules and permit requirements.
For industrial facilities operating spray-booth heaters, ovens, dryers, furnaces, thermal oxidizers, afterburners, vapor incinerators, tenter-frame dryers, process heaters and other miscellaneous combustion equipment, understanding the current Rule 1147 requirements can be critical to avoiding compliance problems.
Energy Environmental Solutions, Inc. (EES) helps facilities with Rule 1147 source testing, NOx testing, CO testing, compliance test protocol development, emissions testing, CEMS/RATA/CGA, engineering studies and regulatory reporting.
What Is South Coast AQMD Rule 1147?
Rule 1147 was adopted in 2008 and most recently amended on May 6, 2022. The current South Coast AQMD rulebook identifies it as Rule 1147 — NOx Reductions from Miscellaneous Sources.
The rule applies to certain gaseous- and/or liquid-fuel-fired combustion equipment requiring a South Coast AQMD permit, when another Regulation XI rule does not already apply to the unit.
Covered equipment can include categories such as:
Thermal oxidizers
Catalytic oxidizers
Afterburners
Vapor incinerators
Ovens
Dryers
Dehydrators
Heaters
Furnaces
Kilns
Calciners
Cookers
Roasters
Tenter-frame dryers
Fabric and carpet dryers
Remediation units
Certain liquid-fuel-fired equipment
The exact applicability depends on the equipment, fuel, rated heat-input capacity, permit status and other provisions of the rule.
Why Does Rule 1147 Matter in 2026?
The environmental reason is straightforward: NOx contributes to ozone and particulate pollution, making NOx reductions an important component of regional air-quality planning.
South Coast AQMD’s Rule 1147 technology assessment explains that the rule’s NOx reductions are an important part of the region’s attainment strategy for federal and state ambient air-quality standards, including standards for ozone, PM2.5 and PM10.
And the need for effective air-quality controls remains highly relevant in 2026. South Coast AQMD’s current 2026 news and regulatory activity includes ozone advisories, particulate-related actions, toxic-air-contaminant rulemaking and additional emissions-control initiatives.
The compliance message for industry:
NOx compliance is not simply about installing a burner or combustion system. Facilities need to demonstrate that applicable equipment actually operates within its required emissions limits.
Latest Rule 1147 Updates for 2026
1. The Current Rule Remains the May 6, 2022 Version
As of August 2026, South Coast AQMD’s current Regulation XI listing identifies Rule 1147 as amended May 6, 2022. There is no indication on the current official rule listing of a newer 2026 amendment to Rule 1147 itself.
That distinction is important.
“Latest 2026 update” does not mean Rule 1147 itself was amended in 2026. Instead, facilities need to consider the current Rule 1147 requirements alongside their current permits and other 2026 regulatory developments.
2. Source Testing Remains a Major Compliance Requirement
For units subject to Rule 1147 with NOx emissions of at least 1 pound per day, the rule requires source testing to demonstrate compliance with applicable NOx and CO limits in the rule or permit.
The testing frequency depends on the equipment’s Rated Heat Input Capacity:
Rated Heat Input Capacity
Source-Test Frequency
< 10 MMBtu/hr
Every 5 calendar years
≥ 10 and < 40 MMBtu/hr
Every 3 calendar years
≥ 40 MMBtu/hr
Every calendar year
≥40 MMBtu/hr with ≥6 months shutdown
Test within 90 days after resumed operation, subject to the rule’s conditions
These intervals are specified in Rule 1147 paragraph (h)(12).
This is one of the most important points for facility managers:
Your source-test due date can depend directly on the equipment’s rated heat-input capacity and NOx emissions.
3. Rule 1147 Requires an Approved Test Protocol
Source testing isn’t simply a matter of sending a technician to the facility and taking measurements.
Rule 1147 requires the operator to submit a source-test protocol to the Executive Officer for approval no later than 90 days before the scheduled source test, subject to the rule’s timing provisions.
For subsequent compliance determinations, protocol resubmission may not be necessary when an approved protocol already exists, provided the unit has not been modified in a way requiring a permit modification and the applicable limits have not become more stringent.
Why does this matter?
Because an improperly planned test can create unnecessary delays, additional costs and potentially unusable compliance data.
Test planning should happen before the test day—not after.
4. Independent Testing Is Required
Rule 1147 requires compliance determinations to be conducted by an independent contractor approved by the Executive Officer under the Laboratory Approval Program for the applicable test methods.
That means facilities should verify that their selected testing company has the appropriate qualifications and approvals for the methods being used.
This is particularly important when a facility is approaching a regulatory deadline.
5. Recordkeeping Still Matters
Rule 1147 requires source-test reports and maintenance records to be maintained for at least five years and made available to South Coast AQMD personnel upon request.
This means compliance doesn’t end when the testing crew leaves the site.
Your facility should maintain:
Source-test reports
Maintenance records
Rated heat-input information
Fuel records where applicable
CEMS records where applicable
Compliance documentation
Approved testing protocols
Equipment modification records
Good documentation can be as important as good testing.
What Emission Limits Does Rule 1147 Establish?
Rule 1147 contains different NOx and CO limits depending on the equipment category, fuel type, process temperature and whether the unit is an in-use unit or subject to the newer Table 2 requirements.
For example, Table 1 includes different limits for equipment such as thermal oxidizers, ovens, heaters, dryers and other combustion equipment.
For certain gaseous-fuel-fired thermal oxidizers, catalytic oxidizers, afterburners and vapor incinerators, the Table 1 NOx limit is 60 ppmv or 0.073 lb/MMBtu, with a CO limit of 1,000 ppmv.
Table 2 establishes more stringent requirements for applicable equipment.
For example, gaseous-fuel-fired thermal oxidizers, catalytic oxidizers, afterburners and vapor incinerators are listed at 20 ppmv or 0.024 lb/MMBtu NOx under Table 2.
Do not assume these numbers automatically apply to your equipment. The applicable limit must be determined from the rule, equipment category, permit and compliance schedule.
A Key 2026 Compliance Option: Less Than 1 Pound of NOx Per Day
Rule 1147 provides an alternative pathway for certain units.
An owner or operator may elect to comply by demonstrating NOx emissions below 1 pound per day averaged over a calendar month, or by meeting an existing permit limit below 1 pound per day, whichever is applicable under the rule.
However, if the facility fails to demonstrate compliance with that option, additional permit and compliance requirements can be triggered.
This makes accurate emissions calculations and recordkeeping particularly important.
Pros of Rule 1147 Compliance
1. Lower NOx Emissions
The primary environmental benefit is reduced NOx emissions from miscellaneous combustion sources.
Lower NOx contributes to regional efforts to address ozone and particulate pollution. South Coast AQMD describes Rule 1147’s NOx reductions as an important component of its attainment strategy.
2. Better Combustion Performance
Testing can reveal problems involving burners, combustion-air systems, controls or operating conditions.
A failed or borderline test can therefore become an opportunity to identify equipment problems.
3. More Reliable Compliance Data
Professional source testing provides measured emissions data instead of relying exclusively on theoretical calculations or equipment specifications.
4. Better Maintenance Decisions
Testing results can help environmental and maintenance teams identify whether combustion equipment needs adjustment, repair or modernization.
5. Improved Regulatory Readiness
Maintaining current testing and maintenance records can make inspections and compliance reviews easier.
Cons and Challenges of Rule 1147
1. Testing Costs
Source testing requires specialized equipment, qualified personnel, laboratory or analytical resources and technical reporting.
2. Production Disruption
Testing may need to occur under specific operating conditions, which can require coordination with production schedules.
3. Protocol Approval Takes Planning
The requirement for an approved test protocol means facilities need to start preparing well before the actual test date.
4. Equipment Modifications Can Change Requirements
Changes to burners, combustion systems, fuel systems or operating conditions may affect the compliance pathway.
5. Multiple Equipment Categories
Rule 1147 covers a wide variety of equipment, so the correct testing approach is not identical for every unit.
6. Testing at the Wrong Operating Condition Can Create Problems
Rule 1147 specifies operating conditions for compliance determinations, including testing at the maximum heat-input range at which the unit normally operates and additional conditions for specified equipment categories.
What Equipment Should California Facilities Review?
If your facility is located in the South Coast AQMD jurisdiction, review Rule 1147 applicability if you operate permitted fuel-fired equipment such as:
The actual applicability must be confirmed against the current rule and permit.
How EES Helps With Rule 1147 Compliance
Energy Environmental Solutions, Inc. (EES) provides technical testing and environmental compliance support for industrial facilities.
Rule 1147 Source Testing
EES can assist with testing programs designed to demonstrate applicable NOx and CO emission compliance.
Compliance Test Protocol Development
EES helps develop testing protocols covering:
Sampling locations
Applicable test methods
Operating conditions
Test runs
QA/QC
Calculations
Reporting requirements
NOx Testing
Accurate NOx measurements are central to Rule 1147 compliance.
CO Testing
Rule 1147 also establishes CO requirements for applicable equipment, making CO testing an important part of many compliance demonstrations.
CEMS / RATA / CGA
For facilities using continuous emissions monitoring systems, EES can support applicable CEMS, RATA and CGA requirements.
Rule 1147 also provides circumstances in which qualifying periodic monitoring or CEMS relative-accuracy testing may be used as part of the source-testing compliance schedule.
Engineering Studies
EES can help facilities evaluate combustion-system performance, emissions trends and potential compliance strategies.
Regulatory Reporting
Testing isn’t complete until the data have been properly evaluated and documented.
EES can help prepare organized technical reports and supporting documentation.
Rule 1147 Compliance Testing Process
A professional compliance project generally follows this sequence:
1. Review the Permit Determine the applicable permit limits and conditions.
2. Confirm Rule Applicability Determine whether Rule 1147 applies to the unit.
3. Determine Testing Frequency Review NOx emissions and rated heat-input capacity.
4. Develop the Test Protocol Select appropriate methods and operating conditions.
5. Submit for Approval Follow South Coast AQMD protocol-approval requirements.
6. Conduct Field Testing Perform NOx, CO and supporting measurements.
7. QA/QC Review Review calibration, field data and calculations.
8. Calculate Emissions Determine compliance with the applicable limit.
9. Prepare the Report Document the test conditions, methods, results and conclusions.
10. Maintain Records Retain required documentation for the applicable period.
Why Proactive Rule 1147 Testing Makes Sense in 2026
South Coast AQMD states that its compliance staff conduct regular inspections to ensure equipment and processes are operating in compliance with applicable clean-air rules.
The agency also explains that failure to correct a Notice to Comply can lead to a Notice of Violation and penalties, while continuing violations can result in daily penalties.
That is why waiting until an inspector identifies a problem is a risky compliance strategy.
A better approach:
Know your limit. Know your test date. Know your operating conditions. Know your documentation.
Rule 1147 Compliance Checklist for 2026
Before your next test, review:
Is the unit subject to Rule 1147?
Is the current permit available?
What NOx limit applies?
What CO limit applies?
What is the unit’s rated heat-input capacity?
Is NOx ≥1 lb/day?
When was the last approved source test?
Is the next test due?
Has the test protocol been approved?
Has the equipment been modified?
Are operating conditions representative?
Are maintenance records current?
Are required fuel meters installed and maintained?
Are five years of required records available?
Is the testing contractor appropriately approved?
2026 Bottom Line
Rule 1147 remains an important South Coast AQMD NOx-compliance requirement in 2026. Although the rule itself was last amended on May 6, 2022, its current requirements continue to govern applicable miscellaneous combustion equipment, including specific source-testing frequencies, test protocols, NOx/CO limits and recordkeeping requirements.
For facilities with applicable equipment, the biggest mistake is assuming that “the equipment has always passed” means the next test can be treated casually.
VOC Destruction Efficiency in California 2026: Latest Updates, Pros, Cons & How EES Helps Industries
VOC destruction efficiency is a critical performance measure for California facilities that use thermal oxidizers, regenerative thermal oxidizers (RTOs), flares, and other air-pollution control systems to reduce volatile organic compound (VOC) emissions.
In 2026, California’s air-quality regulatory environment continues to place strong emphasis on emissions reduction, source testing, monitoring, control-device performance, and accurate reporting. South Coast AQMD has active rulemaking involving VOC-generating industries, including aerospace, wood-product coatings, marine coatings, solvents, and other industrial sources. Rule 1124 for aerospace assembly and component manufacturing was amended on April 3, 2026, while additional VOC-related rulemaking remains active during 2026.
For industries using thermal oxidation, the message is straightforward: having a control device installed is not the same as proving that it is achieving the required VOC control performance. Facilities may need reliable testing and documentation showing that their equipment operates within applicable permit and regulatory requirements.
Energy Environmental Solutions, Inc. (EES) helps industries with VOC Destruction Efficiency Testing, RTO Testing, Thermal Oxidizer Testing, VOC Source Testing, Stack Testing, NOx and CO Testing, Compliance Test Protocol Development, CEMS, RATA, CGA, Engineering Studies, QA/QC, and Regulatory Reporting.
What Is VOC Destruction Efficiency?
VOC destruction efficiency describes the percentage of VOC entering a control device that is destroyed before the treated gas leaves the system. A commonly used calculation is Destruction Efficiency (%) = [(VOC Inlet − VOC Outlet) ÷ VOC Inlet] × 100. For example, if a control device receives 100 units of VOC and 1 unit remains at the outlet, the calculated destruction efficiency is 99%.
That sounds simple, but industrial testing is rarely that simple. Inlet and outlet concentrations, gas flow, moisture, oxygen, temperature, production rate, fuel usage, and other operating conditions can all influence the final result. A facility also needs to understand whether its permit requires destruction efficiency, removal efficiency, capture efficiency, overall control efficiency, or a specific outlet concentration, because these measurements are not interchangeable.
South Coast AQMD’s emissions-reporting guidance specifically says that site-specific test results, the applicable permit, or the applicable rule limit should be used when determining vapor destruction efficiency for certain thermal-oxidation applications.
Is VOC Destruction Efficiency Testing Compulsory in California?
There is an important distinction for facility owners and environmental managers.
There is no single statewide VOC destruction-efficiency testing requirement that applies identically to every California facility. The requirement depends on the facility’s Air District, permit conditions, source category, control equipment, pollutants, applicable state and federal requirements, and specific regulatory provisions.
For example, a Bay Area Air Quality Management District permit for thermal oxidizers establishes a minimum VOC destruction efficiency of 95% by weight along with minimum operating temperatures and continuous temperature monitoring.
Another Bay Area permit issued in 2025 for regenerative thermal oxidizers establishes different destruction-efficiency requirements depending on inlet VOC concentration: greater than 98.5% for higher inlet concentrations, greater than 98% for intermediate concentrations, and greater than 90% for lower concentrations, with an alternative outlet concentration limit also specified. The permit also establishes a minimum combustion-zone temperature and continuous temperature monitoring.
This illustrates why companies should not simply advertise or assume that “99% destruction efficiency” is automatically the legal requirement for every California operation.
Your permit determines what your facility must demonstrate.
Latest California VOC & Destruction-Efficiency Updates for 2026
1. California Air-District Rulemaking Remains Active
South Coast AQMD’s 2026 regulatory activity includes multiple initiatives affecting VOC-emitting industries and pollution-control requirements. Its current rulemaking pages show active work involving aerospace assembly, wood-product coatings, marine and pleasure-craft coatings, and consumer paint thinners and multipurpose solvents.
This is important because VOC compliance is not static. A facility that designed its emissions-control strategy several years ago may need to reassess whether its current processes, materials, control equipment, testing frequency, and documentation continue to satisfy applicable requirements.
The South Coast AQMD 2026 compliance calendar also includes new or updated deadlines affecting VOC-related operations. For example, Rule 1173 requirements beginning January 1, 2026 require certain petroleum and chemical facilities to expand component monitoring using Optical Gas Imaging (OGI) and maintain specified VOC leak thresholds. The same calendar identifies other 2026 control requirements involving captured fugitive emissions and air-pollution-control systems.
2. Rule 1124 Was Amended in April 2026
One significant 2026 development is the amendment of South Coast AQMD Rule 1124 — Aerospace Assembly and Component Manufacturing Operations, which was amended on April 3, 2026.
The rulemaking process examined control options for VOCs and toxic air contaminants associated with aerospace coating operations.
The March 2026 South Coast AQMD staff report evaluated thermal oxidizers and noted that they can achieve destruction efficiencies exceeding 98% when properly designed and operated. The report identifies temperature, residence time, and turbulence/mixing as important thermal-oxidizer design factors.
But the same analysis also identified an important disadvantage: thermal oxidation of certain chlorinated and fluorinated compounds can generate hydrochloric acid (HCl) and hydrofluoric acid (HF). Additional scrubber controls may therefore be necessary, increasing system complexity and operating costs.
What does this mean for industry?
The lesson is bigger than a single rule.
High VOC destruction efficiency does not automatically mean a control technology is appropriate for every chemical stream.
Facilities need to evaluate the complete emissions profile.
3. Thermal Oxidizers Remain an Important VOC-Control Technology
Thermal oxidizers continue to be used for controlling VOC and certain toxic-air-contaminant emissions. South Coast AQMD’s 2026 technical analysis describes thermal oxidizers as combustion devices that convert applicable organic pollutants primarily into carbon dioxide and water, while identifying temperature, residence time, and mixing as key performance factors.
The technology can provide very high VOC destruction efficiency under appropriate conditions.
However, performance depends on how the system is operated. Changes in VOC concentration, gas flow, process chemistry, temperature, residence time, mixing, equipment condition, and operating cycles can affect performance.
That is why source testing remains an important tool for demonstrating actual performance rather than relying solely on equipment design specifications.
4. California Regulators Are Looking at More Than VOCs
Another important 2026 compliance issue is that destroying VOCs does not mean the control system has no other emissions.
South Coast AQMD’s emissions-reporting guidance explains that thermal oxidation can result in emissions of NOx, SOx, CO, particulate matter, and toxic air contaminants in addition to the controlled VOC emissions. The agency encourages operators to use test results when calculating and reporting these emissions.
This creates a broader compliance challenge.
A facility may achieve excellent VOC destruction efficiency while still needing to address combustion-related emissions.
The right question is not simply:
“How efficiently are we destroying VOCs?”
It is:
“What is our complete emissions profile after the control device operates?”
5. EPA Continues to Emphasize Performance Monitoring
The U.S. EPA’s Compliance Assurance Monitoring guidance for thermal oxidizers demonstrates the importance of connecting performance testing with ongoing monitoring. The EPA’s technical guidance uses real facility case studies involving control-device parameters, long-term monitoring data, and performance/compliance testing. The guidance was updated July 2, 2026.
This reinforces an important compliance principle:
A source test provides a performance snapshot; continuous or periodic monitoring helps demonstrate that operating conditions remain consistent with the conditions under which compliance was established.
For facilities, this means testing and monitoring should work together rather than being treated as completely separate activities.
Why Is VOC Destruction Efficiency Testing Important?
Imagine purchasing an expensive industrial control system that is advertised as capable of destroying 99% of VOCs.
Then production conditions change.
The VOC concentration increases. The process begins operating intermittently. A valve develops leakage. Ceramic media becomes fouled. Temperature drops below the expected range. The process gas flow changes.
Does the system still achieve 99%?
That’s exactly why testing matters.
A manufacturer’s performance specification describes what equipment may achieve under defined conditions. A properly designed compliance test provides evidence of what the system is actually achieving under specified operating conditions.
Key Factors That Affect VOC Destruction Efficiency
Temperature
Thermal oxidation requires sufficient temperature for the targeted organic compounds to oxidize effectively. The appropriate temperature depends on the process, pollutant characteristics, equipment design, and applicable permit requirements.
South Coast AQMD identifies temperature as one of the fundamental design factors affecting thermal-oxidizer performance.
Residence Time
The gas must remain in the appropriate combustion environment long enough for the oxidation reaction to occur.
Insufficient residence time can reduce destruction performance.
Turbulence and Mixing
Effective mixing allows the VOC-containing process gas to interact properly with the combustion environment.
Poor mixing can create localized conditions where oxidation is less complete.
VOC Concentration
A control device may behave differently at low, moderate, or high VOC loading.
This is particularly important when production processes are intermittent or have large concentration swings.
Equipment Condition
Burners, valves, seals, fans, ceramic media, dampers, temperature sensors, controls, and ductwork can influence performance.
Capture Efficiency
There is another crucial issue:
The control device cannot destroy VOC emissions that never reach it.
A facility can therefore have excellent destruction efficiency at the oxidizer while still experiencing uncontrolled emissions because of poor capture or fugitive releases.
Pros of VOC Destruction Efficiency Testing
1. Demonstrates Actual Control Performance
Testing provides measurable evidence of control-device performance rather than relying solely on theoretical or manufacturer claims.
2. Supports Permit Compliance
Where required, source-test results can demonstrate compliance with applicable destruction-efficiency or outlet-emission requirements.
3. Helps Identify Problems Early
Testing may reveal declining control performance before the facility experiences a more serious compliance issue.
4. Provides Site-Specific Data
South Coast AQMD specifically recognizes site-specific destruction-efficiency test results as an important source of information for certain emissions calculations.
5. Supports Permit Renewals and Modifications
Reliable testing data can strengthen technical documentation for certain permit-related activities.
6. Helps Optimize Operations
Test results can show how temperature, process loading, production conditions, and other operating variables affect emissions-control performance.
7. Strengthens Environmental Reporting
Accurate data can improve emissions inventories and regulatory reporting.
Cons & Challenges of VOC Destruction Efficiency Testing
Testing Can Be Expensive
Professional source testing requires specialized equipment, experienced personnel, calibration, field labor, analytical work, and technical reporting.
Production Scheduling Can Be Difficult
Testing often needs to occur under representative operating conditions. Coordinating a source test with production schedules can therefore be challenging.
VOC Streams Can Be Variable
Intermittent processes, batch operations, changing solvents, changing production rates, and different raw materials can make representative testing more complicated.
Sampling Can Be Technically Complex
Accurate destruction-efficiency testing may require simultaneous inlet and outlet measurements, flow measurements, oxygen or carbon-dioxide measurements, moisture measurements, and detailed operating-condition documentation.
High Destruction Efficiency Can Have Tradeoffs
Thermal oxidation can create secondary pollutants such as NOx, CO, particulate matter, SOx, and potentially toxic or acidic combustion products depending on the process chemistry.
Regulatory Requirements Can Change
A testing program that was appropriate several years ago may need review as applicable rules, permits, source categories, and Air District policies evolve.
VOC Destruction Efficiency vs. Capture Efficiency
These terms are often confused.
Measurement
What It Means
Capture Efficiency
How much of the process-generated VOC is captured and routed to the control device
Destruction Efficiency
How much of the captured VOC is destroyed by the control device
Removal Efficiency
How much pollutant is removed from the treated stream, depending on the control technology
Overall Control Efficiency
The combined effect of capture and control/destruction
This distinction matters because a facility can have a 99% efficient oxidizer but still release VOCs if only part of the process emissions are captured.
How VOC Destruction Efficiency Testing Is Typically Conducted
A professional testing project generally begins with permit and regulatory review.
The testing team identifies the required pollutants, limits, methods, operating conditions, testing frequency, and reporting requirements.
A compliance test protocol is then developed to establish the sampling locations, test methods, number of runs, operating conditions, QA/QC requirements, calculations, and reporting format.
During testing, the team may measure VOC concentrations at the control-device inlet and outlet while simultaneously documenting operating parameters.
Depending on the applicable method and permit, testing may also involve:
Gas flow
Moisture
Oxygen
Carbon dioxide
Temperature
Fuel consumption
Production rate
VOC loading
Control-device operating parameters
The resulting data are evaluated and used to calculate the applicable destruction/control efficiency.
The final report should clearly document what was tested, how it was tested, under what operating conditions, what the results were, and whether the applicable compliance requirement was met.
What EES Can Test
Energy Environmental Solutions, Inc. (EES) supports facilities with a broad range of emissions-control testing services.
VOC Destruction Efficiency Testing
Evaluation of VOC inlet/outlet concentrations and applicable control efficiency.
RTO Testing
Testing of Regenerative Thermal Oxidizers, including VOC, NOx, CO, and applicable operating parameters.
Thermal Oxidizer Testing
Performance testing for thermal oxidation systems according to applicable requirements.
Source & Stack Testing
Field testing using applicable EPA, CARB, and local Air District methods.
NOx & CO Testing
Evaluation of combustion-related emissions where required.
CEMS / RATA / CGA
Support for continuous emissions monitoring systems and associated certification, relative accuracy testing, and calibration requirements.
Compliance Test Protocol Development
Preparation of testing protocols covering sampling, methods, QA/QC, operating conditions, calculations, and reporting.
Engineering Studies
Technical evaluations of emissions-control systems, operating conditions, and potential compliance strategies.
Regulatory Reporting
Preparation of organized technical reports and supporting documentation for regulatory compliance.
Industries That May Need VOC Destruction Efficiency Testing
Depending on their permit and emissions-control configuration, EES can support facilities in industries such as:
Aerospace Manufacturing
Chemical Manufacturing
Petroleum & Refining
Pharmaceutical Manufacturing
Paint & Coating
Metal Coating
Printing
Food Processing
Composite Manufacturing
Waste Treatment
Solvent-Using Operations
Industrial Manufacturing
Fuel Processing
Petroleum Storage and Loading
Other VOC-emitting industrial operations
The applicable testing requirement is facility-specific.
Why Choose EES for VOC Destruction Efficiency Testing?
When an Air District asks:
“How do you know your control device is achieving the required VOC destruction efficiency?”
The answer should be supported by credible technical data.
EES helps facilities build that evidence through:
VOC Destruction Efficiency Testing
RTO Testing
Thermal Oxidizer Testing
VOC Source Testing
Stack Testing
NOx Testing
CO Testing
CEMS
RATA
CGA
Compliance Test Protocol Development
Engineering Studies
QA/QC
Emissions Calculations
Regulatory Reporting
The goal is simple:
Measure it. Verify it. Document it. Stay compliant.
2026 Compliance Checklist for California Facilities
Before your next VOC compliance test, review:
Your current Air District permit
Applicable VOC rules
Required destruction/control efficiency
Required test frequency
Approved test methods
Sampling locations
Required operating conditions
Production rate during testing
VOC inlet concentration
VOC outlet concentration
Control-device temperature
Flow and moisture requirements
NOx/CO requirements
QA/QC requirements
Reporting deadlines
Continuous-monitoring requirements
Don’t assume that an old source-test protocol automatically remains appropriate.
Review the current requirements before scheduling the test.
The Big 2026 Takeaway
California’s 2026 regulatory activity demonstrates that VOC compliance continues to evolve across multiple industrial sectors. South Coast AQMD has active rulemaking involving aerospace, coatings, solvents, and other VOC-emitting operations, while its current emissions guidance emphasizes the importance of site-specific destruction-efficiency data for applicable thermal-oxidation calculations.
At the same time, regulators and technical guidance continue to emphasize that control-device performance depends on real operating conditions.
A number on a manufacturer’s brochure is not a substitute for a properly conducted compliance demonstration when testing is required.
Is your VOC control device really achieving the efficiency required by your permit?
Are your inlet and outlet measurements defensible?
Are your operating conditions properly documented?
Has your test protocol been reviewed against current requirements?
Are you prepared for your next Air District inspection?
If you are uncertain about any of these questions, a proactive compliance review can help identify potential issues before they become costly problems.
Need VOC Destruction Efficiency Testing in California?
Energy Environmental Solutions, Inc. (EES) helps industrial facilities evaluate and document the performance of VOC control systems.
Destruction Efficiency in California 2026: Latest Updates, Pros, Cons & How EES Helps Industries Stay Compliant
Destruction efficiency is becoming an increasingly important performance metric for California facilities that use thermal oxidizers, regenerative thermal oxidizers (RTOs), flares, vapor-control systems, and other air-pollution control equipment to reduce VOC and other organic emissions.
In simple terms, destruction efficiency measures how much of a pollutant entering a control device is actually destroyed before the treated gas is released. A commonly used calculation is:
But achieving a high percentage during one test is not necessarily the same as maintaining compliant performance during everyday operation.
California’s 2026 regulatory environment continues to emphasize emission reductions, monitoring, source testing, toxic-air-contaminant controls, and reliable emissions data. South Coast AQMD’s 2026 rule calendar contains more than two dozen planned rule amendments and adoptions addressing particulate matter, toxic air contaminants, monitoring, New Source Review, and other air-quality objectives.
For facilities using thermal oxidation or other control technologies, that creates a growing need for accurate destruction-efficiency testing and defensible compliance documentation.
Energy Environmental Solutions, Inc. (EES) helps industries with Destruction Efficiency Testing, VOC Testing, RTO Testing, Thermal Oxidizer Testing, Source & Stack Testing, CEMS, RATA, CGA, Compliance Test Protocol Development, Engineering Studies, QA/QC, and Regulatory Reporting.
What Is Destruction Efficiency?
Destruction efficiency, often called Destruction Removal Efficiency (DRE), describes the percentage of a pollutant that a control device removes through destruction.
For example, if a control device receives 100 pounds of VOCs and only 1 pound remains in the outlet gas, the calculated destruction efficiency would be approximately 99%.
This measurement is particularly important for equipment such as:
Regenerative Thermal Oxidizers (RTOs)
Thermal oxidizers
Catalytic oxidizers
Afterburners
Flares
VOC control systems
Certain combustion-based control devices
However, destruction efficiency is not the same as capture efficiency.
A facility can have an excellent control device but still release pollutants if the process exhaust is not effectively captured and routed to the control equipment.
That is why compliance evaluations may need to consider capture efficiency + control/destruction efficiency + operating conditions + actual emissions.
Is Destruction Efficiency Testing Compulsory in California?
There is an important distinction.
California does not have one universal destruction-efficiency testing requirement that applies identically to every industrial facility.
Whether a facility must demonstrate destruction efficiency depends on factors including:
Facility location
Local Air District
Air permit
Applicable regulation
Source category
Pollutant
Control technology
Required control efficiency
Federal requirements
State requirements
Permit-specific testing conditions
A current South Coast AQMD emissions-reporting guideline specifically instructs facilities using thermal oxidation to use site-specific destruction-efficiency test results, the applicable permit, or the applicable rule limit when determining vapor-destruction efficiency.
This is an important compliance message:
Don’t assume your facility’s required destruction efficiency—verify it from the applicable permit and regulation.
Latest California Updates in 2026
1. California Continues Strengthening Air-Quality Controls
South Coast AQMD’s 2026 rulemaking program includes more than two dozen planned rule amendments and adoptions.
The agency’s priorities include:
PM reduction
Toxic-air-contaminant controls
Updated toxic-air-contaminant lists
New Source Review
Monitoring requirements
Community emission-reduction objectives
The agency says these activities support the 2016 and 2022 Air Quality Management Plans, 2024 PM Plan, federal and state air-quality standards, and AB 617 Community Emission Reduction Plans.
For facilities using VOC destruction systems, this reinforces the importance of having reliable performance data.
2. Thermal Oxidation Remains an Important Control Technology
South Coast AQMD continues to evaluate thermal oxidation as an emissions-control option.
A March 2026 South Coast AQMD staff report evaluating aerospace coating controls recognized that thermal oxidizers can technically achieve high destruction efficiencies for certain VOC and toxic compounds. However, the agency also identified limitations for some chlorinated and fluorinated compounds because thermal oxidation can produce HCl and HF, requiring additional controls such as scrubbers.
The lesson for industry is important:
A high destruction-efficiency percentage does not automatically mean a control technology is appropriate for every pollutant.
The entire emissions profile must be evaluated.
3. Regulators Are Looking Beyond a Single Performance Number
South Coast AQMD’s 2026 activities demonstrate a broader focus on monitoring, toxic air contaminants, particulate matter, and emissions data rather than relying on a single compliance measurement.
A control device may destroy VOCs while simultaneously generating other combustion-related pollutants.
South Coast AQMD’s emissions-reporting guidance specifically states that thermal oxidation can generate NOx, SOx, CO, PM, and toxic air contaminants, and encourages operators to use site-specific test results for emissions calculations when available.
Therefore, a strong testing program should evaluate the complete picture.
4. Real-World 2026 Cases Show Why Performance Verification Matters
In June 2026, South Coast AQMD hearing-board documents involving Chiquita Canyon included conditions requiring equipment modifications designed to maintain sufficient flare operation and methane content for destruction efficiency consistent with regulatory requirements.
Earlier 2026 correspondence from South Coast AQMD also discussed the relationship between operating conditions, temperature, equipment design, source-test results, and destruction efficiency at the facility.
Although this example involves landfill-gas combustion rather than a conventional industrial RTO, it illustrates a broader principle:
Regulators can require evidence that operating conditions actually support the required destruction performance.
Why Is Destruction Efficiency Testing Important?
A control device manufacturer’s guarantee may say 98%, 99%, or higher.
But what happens after the equipment has been installed?
What happens when:
VOC loading changes?
Production increases?
Temperature fluctuates?
Ceramic media becomes fouled?
Valves begin leaking?
Airflow changes?
Process chemistry changes?
The burner operates differently?
The capture system develops leaks?
That’s where compliance testing becomes valuable.
Testing converts assumptions into measurable evidence.
Key Factors Affecting Destruction Efficiency
Temperature
Thermal oxidation generally requires sufficient temperature for effective oxidation.
If the temperature falls outside the required operating range, destruction performance may decline.
Residence Time
The contaminated gas needs sufficient time in the appropriate combustion environment.
Insufficient residence time can reduce destruction performance.
Turbulence & Mixing
Effective mixing is essential to expose the pollutant-containing gas to the required oxidation conditions.
VOC Concentration
A control system can perform differently depending on the concentration and composition of the incoming VOC stream.
Equipment Condition
Valves, burners, seals, ceramic media, sensors, ductwork, fans, and controls can all affect system performance.
Capture Efficiency
Even a highly efficient RTO cannot destroy pollutants that never reach it.
This makes capture and destruction efficiency two different but interconnected compliance considerations.
Pros of Destruction Efficiency Testing
1. Demonstrates Control Performance
Testing provides measurable evidence of how effectively the control device is destroying pollutants.
2. Supports Regulatory Compliance
Where required by a permit or regulation, test results can support compliance demonstrations.
3. Identifies Problems Early
Testing may reveal declining control efficiency before the problem becomes a larger compliance issue.
4. Supports Permit Applications
Reliable test data can be useful for permit modifications, renewals, and engineering evaluations.
5. Provides Site-Specific Data
South Coast AQMD specifically encourages the use of site-specific destruction-efficiency test results where available for emissions calculations.
6. Improves Operational Understanding
Testing can help facility engineers understand how production conditions affect control-device performance.
Cons & Challenges of Destruction Efficiency Testing
Professional testing also has challenges.
Testing Costs
Specialized source-testing equipment, qualified personnel, laboratory analysis, and reporting can increase project costs.
Production Coordination
Testing may need to occur under representative operating conditions, requiring coordination with production.
Complex Sampling
Some control-efficiency tests require simultaneous measurements at the inlet and outlet.
Variable VOC Streams
Changing process chemistry can make it difficult to establish representative testing conditions.
Secondary Pollutants
Thermal oxidation can create additional pollutants such as NOx, CO, SOx, PM, and certain toxic or acidic compounds, depending on the material being treated.
Documentation Requirements
A technically correct test can still create compliance problems if the supporting protocol, calibration, operating-condition records, calculations, or report are incomplete.
Destruction Efficiency vs. Removal Efficiency vs. Capture Efficiency
These terms are often confused.
Term
What It Measures
Destruction Efficiency
Percentage of pollutant destroyed by the control device
Removal Efficiency
Percentage of pollutant removed from the treated stream; the exact meaning depends on the control process
Capture Efficiency
Percentage of process emissions successfully captured and routed to the control device
Overall Control Efficiency
Combined effect of capture and control/destruction
A facility should understand exactly which metric its permit or regulation requires.
How Destruction Efficiency Testing Is Typically Performed
A professional testing program can include:
1. Permit Review
Identify the required control efficiency, pollutants, test frequency, and applicable methods.
2. Test Protocol Development
Define sampling locations, methods, operating conditions, number of runs, QA/QC, and calculations.
3. Pre-Test Coordination
Coordinate production and control-device operation to establish representative conditions.
4. Equipment Calibration
Prepare and calibrate sampling and analytical equipment.
5. Inlet Testing
Measure the pollutant concentration entering the control device.
6. Outlet Testing
Measure the pollutant concentration leaving the control device.
7. Operating Data Collection
Document temperature, flow, fuel use, production rate, oxygen, pressure, and other applicable parameters.
8. Calculations
Calculate destruction/control efficiency and mass emissions using the applicable methodology.
9. QA/QC Review
Verify data quality, calibration information, field records, and laboratory results.
10. Final Reporting
Prepare a technically defensible report for the facility and regulatory agency when required.
How EES Helps Industries
Energy Environmental Solutions, Inc. (EES) provides comprehensive emissions-testing and environmental compliance services for California industries.
Destruction Efficiency Testing
EES helps facilities design and perform testing programs to determine whether applicable control devices are achieving required performance.
RTO Testing
For regenerative thermal oxidizers, EES can support:
VOC inlet testing
VOC outlet testing
VOC destruction/control efficiency
NOx testing
CO testing
Operating-condition verification
Thermal Oxidizer Testing
EES can evaluate thermal oxidizer performance according to applicable permit and regulatory requirements.
Source & Stack Testing
Professional source and stack testing using applicable EPA, CARB, and local Air District methods.
Compliance Test Protocol Development
EES develops protocols covering:
Test methods
Sampling locations
Operating conditions
Test runs
QA/QC
Calculations
Reporting
CEMS, RATA & CGA
EES also supports:
CEMS Certification | RATA | CGA | QA/QC | Monitoring
Engineering Studies
Engineering evaluations can help facilities understand emissions-control performance and identify potential improvement opportunities.
Compliance Reporting
EES provides organized technical documentation including field data, calculations, QA/QC records, operating information, and final test results.
Industries That May Need Destruction-Efficiency Testing
Depending on their control technology and permit requirements, EES can support facilities in industries such as:
Aerospace
Chemical Manufacturing
Petroleum & Refining
Pharmaceutical Manufacturing
Paint & Coating
Metal Finishing
Printing
Food Processing
Waste Treatment
Recycling
Composite Manufacturing
Fuel Processing
Solvent-Using Industries
Industrial Manufacturing
Why Choose EES?
When a regulator asks:
“How do you know your control device is achieving the required efficiency?”
A manufacturer’s brochure isn’t always enough.
You need credible, documented, site-specific evidence when your permit or regulation requires it.
The 2026 Compliance Message for California Industry
California’s 2026 regulatory activity shows that air-quality management is continuing to focus on emission reductions, monitoring, toxic-air contaminants, particulate matter, and community exposure.
At the same time, regulators continue to use site-specific data and permit conditions to evaluate whether emission-control equipment is achieving required performance. South Coast AQMD’s current emissions guidance specifically points to site-specific destruction-efficiency testing, permit requirements, or applicable rule limits when determining destruction efficiency for certain thermal-oxidation applications.
That makes proactive testing a smart compliance strategy.
Don’t wait until an underperforming control device becomes a regulatory problem.
Ask:
Is your VOC control efficiency still meeting your permit requirement?
Are your inlet and outlet measurements defensible?
Are your operating conditions properly documented?
Has your control device been tested under representative conditions?
Is your current test protocol aligned with your permit?
If you don’t know the answer, it may be time for a compliance review.
Need Destruction Efficiency Testing in California?
Energy Environmental Solutions, Inc. (EES) helps industrial facilities evaluate, document, and improve emissions-control performance.
RTO Testing in California (2026): Latest Updates, Pros, Cons & How EES Helps Industries Stay Compliant
California’s industrial air-quality requirements continue to evolve in 2026, making Regenerative Thermal Oxidizer (RTO) testing an important compliance consideration for facilities using RTOs to control VOCs and other air pollutants.
An RTO is a sophisticated air-pollution control device that uses ceramic heat-recovery media and high-temperature oxidation to destroy combustible pollutants. But installing an RTO does not automatically prove compliance. Facilities may need source testing, operating-condition verification, continuous monitoring, and documentation demonstrating that the system is achieving the performance required by its permit or applicable regulations.
Recent California regulatory activity reinforces this point. South Coast AQMD continues developing and updating rules involving VOC emissions, NOx, toxic air contaminants, particulate matter, monitoring, and New Source Review. Its 2026 work also includes proposed amendments affecting industrial combustion equipment and air-quality controls.
For facilities operating RTOs, this makes proactive testing and compliance planning increasingly valuable.
Energy Environmental Solutions, Inc. (EES) helps industries with RTO Testing, Thermal Oxidizer Testing, VOC Testing, Source & Stack Testing, NOx & CO Testing, CEMS, RATA, CGA, Compliance Test Protocol Development, Engineering Studies, and Regulatory Reporting.
Regenerative Thermal Oxidizer Testing
What Is RTO Testing?
RTO testing evaluates the performance and emissions of a Regenerative Thermal Oxidizer under specified operating conditions.
RTOs are commonly used to control VOC emissions from processes such as:
Coating and painting
Chemical manufacturing
Printing
Solvent-based operations
Aerospace manufacturing
Food and industrial processing
Pharmaceutical manufacturing
Petroleum operations
Waste treatment
Other VOC-generating industrial processes
An RTO generally uses ceramic heat-exchange media to recover heat from the oxidized exhaust and transfer that heat to incoming process gas. This can make the technology highly energy-efficient compared with some conventional thermal oxidizer configurations.
However, the RTO must operate correctly. Testing can help determine whether the system is meeting applicable VOC destruction/control requirements and whether combustion-related emissions such as NOx and CO remain within applicable limits.
Is RTO Testing Compulsory in California?
This is an important distinction.
RTO testing is not automatically compulsory for every facility in California simply because the facility owns an RTO.
Testing requirements depend on factors such as:
Facility location
Air District
Permit conditions
Applicable rules
Type of process
Pollutants being controlled
RTO design
Required control efficiency
Operating conditions
Federal requirements
State requirements
Testing provisions in the facility’s permit
For example, a current San Joaquin Valley Air Pollution Control District permit for a facility using an RTO requires source testing of NOx, VOC at the RTO inlet, VOC at the RTO outlet, and VOC control efficiency within 60 days of startup and annually thereafter. The permit also specifies EPA/ARB test methods, advance notification, an approved source-test plan, and reporting requirements.
This is why facilities should review their individual permit and applicable Air District requirements rather than assuming that one statewide testing schedule applies to every RTO.
Latest California RTO Updates in 2026
1. Air District Rulemaking Remains Active
South Coast AQMD’s 2026 rulemaking agenda shows substantial ongoing regulatory activity involving industrial emissions. Proposed amendments include rules covering NOx from industrial boilers and process heaters, toxic air contaminants, particulate matter, monitoring, reporting, recordkeeping, and New Source Review.
For RTO operators, this matters because an RTO can control VOC emissions while its combustion process may also affect other pollutants.
A compliance program therefore needs to consider the whole emission profile, not only VOC destruction efficiency.
2. South Coast AQMD Continues Evaluating Thermal Oxidizers
A March 2026 South Coast AQMD staff report evaluating controls for aerospace coating operations discusses thermal oxidizers as a technology capable of achieving high destruction efficiencies for applicable VOC and toxic compounds.
The report also highlights an important limitation: thermal oxidation of certain chlorinated and fluorinated compounds can generate HCl and HF, potentially requiring additional scrubbing equipment. South Coast AQMD concluded that thermal oxidation was not the most practical control option for most of the aerospace coating applications evaluated in that particular rulemaking.
What does this mean for RTO operators?
The best control strategy depends on the specific pollutants in the process stream. A high destruction efficiency for VOCs does not necessarily mean the technology is optimal for every chemical mixture.
3. RTOs Remain an Established VOC Control Technology
South Coast AQMD’s BACT materials continue to recognize thermal oxidizers, including RTOs, as established control technologies for certain applications. The District’s BACT records include a regenerative thermal oxidizer determination for a metal-coating operation.
The District has also historically identified RTOs as BACT for certain VOC-control applications.
This means RTO technology remains relevant—but the required performance level is application-specific.
4. RTOs Can Have Strict Operating Conditions
A recent Valley Air District permit provides a useful real-world example.
The permit requires the RTO to operate with:
Minimum combustion-chamber temperature of 1,400°F
Minimum retention time of 0.5 seconds
Continuous temperature monitoring
Annual source testing
Approved testing methods
Advance notification
An approved source-test plan
Regulatory reporting
The permit also establishes pollutant-specific emission limits and requires testing of VOC control efficiency.
This illustrates why RTO testing is more than collecting a stack sample. Operating conditions and documentation can be just as important.
What Does RTO Testing Typically Measure?
Depending on the applicable permit and test protocol, an RTO testing program may evaluate:
The actual parameters and methods should be established from the applicable permit, Air District requirements, and approved test protocol.
How RTO Testing Works
A typical compliance project may involve several stages.
1. Permit Review
The testing team first reviews the facility’s permit and applicable regulatory requirements.
2. Test Protocol Development
A detailed protocol identifies sampling locations, methods, operating conditions, test runs, QA/QC requirements, and calculations.
3. Pre-Test Coordination
Testing is scheduled around representative production conditions.
4. Equipment Calibration
Sampling and measurement equipment is checked and calibrated according to applicable requirements.
5. Inlet & Outlet Testing
Where control efficiency is required, pollutant concentrations may be measured before and after the RTO.
6. Operating-Condition Documentation
Important parameters such as temperature, flow, production rate, fuel use, and process conditions may be documented.
7. QA/QC Review
Field and laboratory data are reviewed for completeness and technical validity.
8. Emissions Calculations
Results are converted into the units required by the applicable permit or rule.
9. Final Report
A comprehensive technical report is prepared for the facility and, when required, submitted to the applicable Air District.
Pros of RTO Testing
1. Demonstrates Compliance
Professional testing can provide documented evidence that an RTO is meeting applicable permit requirements.
2. Verifies VOC Control Efficiency
Testing can determine whether the RTO is achieving the required VOC destruction or control efficiency.
3. Identifies Equipment Problems
Testing may reveal issues involving:
Burner performance
Temperature control
Valve operation
Heat-recovery media
Airflow
Process loading
Combustion conditions
Early identification can allow operators to address problems before they become larger compliance concerns.
4. Supports Permit Requirements
Testing documentation can support:
Permit renewals
Permit modifications
Initial startup compliance
Periodic compliance demonstrations
Regulatory inspections
5. Improves Emissions Data
Site-specific test results can provide stronger emissions information than relying exclusively on generic assumptions or emission factors.
6. Supports Environmental Performance
An appropriately designed and operated RTO can substantially reduce VOC emissions from applicable industrial processes.
Cons & Challenges of RTO Testing
RTO testing also presents practical challenges.
Cost
Professional source testing requires specialized equipment, trained personnel, field time, laboratory analysis where applicable, and technical reporting.
Production Coordination
Testing often needs representative production conditions. Facilities may therefore need to coordinate testing with production schedules.
Complex Sampling
Measuring VOC concentrations and calculating control efficiency can require simultaneous inlet/outlet measurements and careful process documentation.
Operating Conditions Matter
A test performed under non-representative conditions may not provide a meaningful picture of normal performance and may not satisfy the applicable permit requirements.
Combustion Emissions
An RTO destroys VOCs through combustion, but the process can generate NOx, CO and other combustion-related emissions depending on the fuel, temperature, process gas, and equipment design.
Maintenance Requirements
RTOs contain valves, ceramic media, burners, controls, sensors, blowers, and other components that require appropriate maintenance.
Changing Regulations
California’s regulatory framework continues to change. Facilities need to periodically verify whether their existing testing program remains aligned with current permit and Air District requirements.
RTO Testing vs. Thermal Oxidizer Testing
The terms are related but not identical.
Thermal oxidizer testing is a broad term covering different thermal oxidation technologies.
RTO testing specifically refers to Regenerative Thermal Oxidizers.
An RTO uses regenerative heat recovery, typically through ceramic media and alternating flow paths, to improve energy efficiency.
Therefore, an RTO testing program may have additional operating considerations related to:
Regenerative chambers
Ceramic heat-exchange media
Valve switching
Purge cycles
Temperature profiles
Flow direction
Heat recovery
Pressure balance
Why RTO Testing Is Becoming More Important
California’s regulatory environment is moving toward greater emphasis on emissions reductions, monitoring, documentation, and control technology performance.
South Coast AQMD’s 2026 rulemaking activity includes proposed requirements addressing NOx, toxic air contaminants, particulate matter, monitoring, reporting, and New Source Review.
At the same time, real-world permits demonstrate that RTOs can be subject to detailed requirements for:
Thermal Oxidizer Testing in California (2026): Latest Updates, Pros, Cons & How EES Helps Industries Stay Compliant
California continues to maintain some of the nation’s most demanding requirements for controlling VOC and toxic air contaminant emissions from industrial operations. For facilities using thermal oxidizers, regenerative thermal oxidizers (RTOs), catalytic oxidizers, afterburners, or related combustion-control equipment, performance testing can be an important part of demonstrating that the control device is actually achieving the required emissions-control performance.
A key 2026 development is that South Coast AQMD is actively evaluating control technologies and emissions requirements across several industrial sectors. Its March 2026 staff report for aerospace coating operations, for example, discusses thermal oxidizers as VOC and toxic-air-contaminant controls and notes that they can achieve destruction efficiencies above 98% in appropriate applications. At the same time, the report highlights an important challenge: thermal oxidation of certain compounds can create secondary pollutants such as HCl and HF, potentially requiring additional control equipment.
For industrial facilities, this means thermal oxidizer testing should not be viewed simply as a one-time emissions test. Temperature, residence time, combustion conditions, VOC destruction efficiency, NOx, CO, and potentially other pollutants all need to be considered according to the applicable permit and Air District requirements.
Energy Environmental Solutions, Inc. (EES) helps California industries with Thermal Oxidizer Testing, VOC Testing, Source & Stack Testing, NOx and CO Testing, Compliance Test Protocol Development, CEMS/RATA/CGA, Engineering Studies, and Regulatory Reporting.
What Is Thermal Oxidizer Testing?
A thermal oxidizer destroys VOCs and other combustible pollutants by oxidizing them at elevated temperatures.
Testing can be used to determine whether the equipment is achieving the required destruction or removal efficiency (DRE) and whether emissions from the control device comply with applicable permit or regulatory limits.
Depending on the facility and permit, testing may evaluate:
VOC destruction efficiency
VOC concentration
NOx emissions
CO emissions
CO₂
O₂
Flow rate
Temperature
Residence time
Combustion conditions
Particulate matter
Toxic air contaminants, where applicable
The exact testing requirements are facility- and permit-specific. There is no single California-wide thermal-oxidizer test that automatically applies to every facility.
Latest California Thermal Oxidizer Updates for 2026
1. South Coast AQMD Is Actively Evaluating Thermal Oxidizers
One of the clearest 2026 regulatory developments comes from South Coast AQMD’s work on Proposed Amended Rule 1124, covering aerospace assembly and component manufacturing operations.
The March 2026 staff report evaluates thermal oxidizers as a potential control technology for VOC and toxic-air-contaminant emissions. South Coast AQMD states that thermal oxidizers can achieve destruction efficiencies exceeding 98% under suitable operating conditions.
However, the agency also identifies limitations for some compounds. For example, thermal oxidation of chlorinated and fluorinated compounds can generate acidic byproducts such as hydrochloric acid and hydrofluoric acid, potentially requiring scrubbers and additional controls.
What this means for industry: choosing a thermal oxidizer is not simply about achieving a high VOC destruction percentage. Facilities must also evaluate the pollutants created by the combustion process.
2. 2026 Rulemaking Continues Across California’s Industrial Air Sector
South Coast AQMD’s 2026 regulatory agenda includes numerous proposed amendments and new rules addressing particulate matter, toxic air contaminants, monitoring, New Source Review, and other air-quality requirements.
This broader regulatory activity matters to facilities operating thermal oxidizers because a control device may address one pollutant while creating or affecting another.
For example, South Coast AQMD’s emissions-reporting guidance for thermal oxidation notes that when VOC vapors are destroyed through thermal oxidation, NOx, SOx, CO, PM, and toxic air contaminants may also be generated. The agency encourages operators to use site-specific test results where available for emissions calculations.
That makes comprehensive testing increasingly valuable.
3. Source Testing Can Be a Permit Requirement
Thermal oxidizer testing requirements are often written directly into individual facility permits.
For example, a Bay Area Air Quality Management District permit requires a thermal oxidizer to be source tested annually for VOC control efficiency as well as NOx and CO emissions, with results reported to the District. The permit also specifies continuous temperature monitoring and recordkeeping requirements.
This demonstrates an important point:
Thermal oxidizer testing frequency and pollutants are determined by the applicable permit and regulatory requirements.
Some facilities may require annual testing; others may have different schedules or testing triggers.
4. California Facilities Continue Using Performance Testing to Demonstrate Control Efficiency
South Coast AQMD Hearing Board documents also show real-world applications of thermal oxidizers.
In a 2025 case involving a petroleum facility, a portable thermal oxidizer was allowed temporarily to replace an afterburner, subject to conditions including a minimum overall VOC control efficiency of 99% and a performance test shortly after startup to demonstrate compliance.
Although that order was issued in 2025, it remains a useful example of how regulators can use performance testing to verify control-device performance during temporary or modified operating conditions.
Why Is Thermal Oxidizer Testing Important?
A thermal oxidizer may look like a simple solution:
VOC-containing gas → high-temperature combustion → cleaner exhaust
But real-world performance depends on several variables.
If the temperature is too low, residence time is inadequate, mixing is poor, or the system is overloaded, destruction efficiency can decline.
Testing helps answer the critical question:
Is the thermal oxidizer actually performing as required under real operating conditions?
Key Parameters That Can Affect Performance
Temperature
Thermal oxidation requires sufficient temperature to initiate and maintain the oxidation reaction.
Temperature requirements vary depending on the equipment, pollutants, permit, and process.
Residence Time
The contaminated gas needs enough time inside the combustion chamber for the oxidation reaction to occur effectively.
Turbulence & Mixing
Good mixing of combustion air and contaminated gas is essential for consistent oxidation.
South Coast AQMD specifically identifies temperature, residence time, and turbulence/mixing as important design factors for thermal oxidizers.
VOC Loading
An oxidizer operating with a highly variable VOC concentration may behave differently from one receiving a stable waste stream.
Testing under representative operating conditions is therefore critical.
Pros of Thermal Oxidizer Testing
1. Demonstrates Compliance
Testing can provide documented evidence that the control device is meeting applicable permit requirements.
2. Verifies VOC Destruction Efficiency
Testing can determine whether the thermal oxidizer is achieving its required VOC control efficiency.
3. Identifies Performance Problems
Testing can reveal declining control efficiency, combustion problems, unusual emissions, or operational conditions requiring investigation.
4. Supports Permit Compliance
Reliable source-test results can support permit renewals, modifications, inspections, and regulatory reporting.
5. Improves Environmental Performance
Properly operated thermal oxidizers can substantially reduce VOC emissions and associated air-quality impacts.
6. Provides Better Emissions Data
Site-specific testing can provide more defensible information than relying exclusively on generic emission factors.
Cons & Challenges of Thermal Oxidizer Testing
Thermal oxidizer testing also comes with challenges.
Testing Costs
Professional source testing requires specialized equipment, trained personnel, laboratory analysis where applicable, and technical reporting.
Production Scheduling
Testing may need to be performed during specific operating conditions, making coordination with production important.
Complex Testing Requirements
VOC destruction efficiency testing can require simultaneous inlet and outlet measurements, operating-condition documentation, and carefully designed sampling procedures.
Secondary Pollutants
Thermal oxidation can produce NOx, CO, SOx, PM, and potentially toxic or acidic combustion byproducts, depending on the waste stream. South Coast AQMD specifically highlights these considerations in its emissions-reporting guidance.
Equipment Maintenance
Burners, combustion chambers, temperature sensors, controls, fans, dampers, and related equipment need appropriate maintenance to maintain performance.
Regulatory Changes
California’s air-quality regulations continue evolving, making it important for facilities to verify current requirements rather than relying on an old test protocol.
Thermal Oxidizer Testing: What May Be Tested?
A facility’s testing program may include:
Parameter
Why It May Be Tested
VOC
Determine emissions and/or destruction efficiency
NOx
Evaluate combustion-related emissions
CO
Identify incomplete combustion
CO₂
Support combustion and emissions calculations
O₂
Support emissions calculations and combustion evaluation
Flow Rate
Determine mass emissions
Temperature
Verify operating conditions
PM
Evaluate particulate emissions where applicable
Toxic Air Contaminants
Evaluate pollutants specific to the process
Inlet/Outlet VOC
Calculate control efficiency
The exact parameters should always be determined from the facility permit, applicable Air District rules, approved test protocol, and regulatory requirements.
How Energy Environmental Solutions, Inc. Helps Industries
Energy Environmental Solutions, Inc. (EES) provides comprehensive testing and engineering support for facilities using thermal oxidizers and other air pollution control devices.
Thermal Oxidizer Performance Testing
EES can help facilities evaluate thermal oxidizer performance through appropriate source-testing programs.
VOC Destruction Efficiency Testing
We can support testing programs designed to determine VOC inlet and outlet concentrations and control efficiency, where required.
NOx & CO Testing
Because combustion can create secondary pollutants, EES can support testing for NOx and CO where required by permits or regulations.
Source & Stack Testing
Our team provides source and stack testing using applicable EPA, CARB, and local Air District methods.
Compliance Test Protocol Development
Before testing begins, a well-developed protocol can define:
Sampling locations
Test methods
Operating conditions
Number of runs
QA/QC requirements
Analytical procedures
Calculations
Reporting requirements
CEMS, RATA & CGA
EES also supports:
CEMS Certification
RATA
CGA
QA/QC programs
Monitoring support
Engineering Studies
Engineering evaluations can help facilities understand equipment performance and identify potential emissions-control improvements.
Regulatory Reporting
After testing, EES can provide technical reports containing emissions calculations, field information, QA/QC documentation, and test results suitable for regulatory review.
Industries That May Use Thermal Oxidizers
Thermal oxidizers are used across many industrial applications, including:
Chemical Manufacturing
Aerospace Manufacturing
Petroleum & Refining
Pharmaceutical Manufacturing
Printing Operations
Coating Operations
Food Processing
Industrial Manufacturing
Waste Treatment
Landfill Gas Control
Solvent-Using Operations
Fuel Processing
Composite Manufacturing
The applicable testing requirements vary significantly by industry and facility.
Why Choose EES for Thermal Oxidizer Testing?
When a thermal oxidizer is part of your compliance strategy, the question isn’t simply “Can it burn VOCs?”
The real questions are:
Is it achieving the required control efficiency?
Are operating conditions documented?
Are secondary emissions being evaluated?
Is the testing performed according to the applicable protocol?
Is the final report defensible during an inspection?
EES helps facilities address these questions through:
✔ Experienced environmental professionals
✔ California regulatory expertise
✔ Source & stack testing
✔ VOC testing
✔ Thermal oxidizer performance testing
✔ NOx & CO testing
✔ Compliance test protocols
✔ CEMS/RATA/CGA support
✔ Engineering studies
✔ QA/QC documentation
✔ Inspection-ready reporting
✔ Responsive technical support
Don’t Wait Until Your Thermal Oxidizer Fails a Test
A thermal oxidizer is a control device, not a guarantee of compliance.
Its performance depends on equipment condition, operating parameters, waste-stream characteristics, combustion conditions, monitoring, and maintenance.
With California continuing to develop and amend air-quality requirements in 2026, proactive testing and compliance planning can help industrial facilities identify potential issues before they become larger regulatory problems. South Coast AQMD’s current rulemaking activity and facility-specific permit requirements demonstrate why companies should review their testing obligations regularly.
Need Thermal Oxidizer Testing in California?
Energy Environmental Solutions, Inc. can help with:
Air Emissions Testing in California (2026): Latest Updates, Pros, Cons & How EES Helps Industries Stay Compliant
California continues to operate one of the most comprehensive air-quality regulatory systems in the United States. In 2026, air emissions testing, source testing, stack testing, emissions monitoring, QA/QC, and compliance reporting remain important tools for industrial facilities demonstrating compliance with air permits and applicable state, federal, and local requirements.
The regulatory environment is also evolving. South Coast AQMD’s 2026 rulemaking calendar includes more than two dozen planned rule amendments and adoptions addressing particulate matter, toxic air contaminants, monitoring, New Source Review, and other air-quality objectives. At the same time, CARB continues updating statewide programs and test methods, while EPA’s current implementation framework continues to rely on emissions inventories, monitoring, modeling, and control strategies to demonstrate progress toward federal air-quality standards.
For industrial operators, this means one thing: accurate emissions data and defensible testing are becoming increasingly important.
Energy Environmental Solutions, Inc. (EES) helps facilities manage this process through professional Air Emissions Testing, Source & Stack Testing, Compliance Test Protocol Development, CEMS Certification, RATA, CGA, QA/QC, Engineering Studies, and Regulatory Reporting.
Emissions Testing
What Is Air Emissions Testing?
Air emissions testing is the measurement and evaluation of pollutants released from industrial processes, combustion equipment, stacks, vents, and other emission sources.
Depending on the facility and permit requirements, testing may address pollutants such as:
NOx – Nitrogen Oxides
SOx – Sulfur Oxides
CO – Carbon Monoxide
VOC – Volatile Organic Compounds
PM – Particulate Matter
PM10
PM2.5
Hazardous Air Pollutants (HAPs)
Air toxics
Metals
Hexavalent chromium
Dioxins and furans
Ammonia
Greenhouse gases
California’s stationary-source testing framework can involve CARB, EPA, and local Air District test methods, with requirements varying according to the applicable agency and regulation. CARB specifically notes that compliance testing requirements can include published CARB, EPA, or other approved test methods.
Why Is Air Emissions Testing Important in California?
California’s air-quality programs are built around controlling emissions from both mobile and stationary sources. CARB identifies stationary point sources such as power plants, oil refineries, manufacturing facilities, and food-processing plants as important categories of permitted emission sources.
For facilities subject to permits, testing provides regulators and operators with information about the actual performance of emission sources. It can also support permit demonstrations, compliance determinations, emissions inventories, engineering evaluations, and corrective actions.
South Coast AQMD’s Annual Emissions Reporting program illustrates the importance of accurate emissions information: facilities meeting specified reporting thresholds must submit annual emissions reports, and the information is used to support air-quality planning and evaluation of clean-air strategies.
Latest California Air Emissions Updates for 2026
1. California’s Regulatory Activity Remains High
South Coast AQMD announced a 2026 rule calendar containing more than two dozen planned rule amendments and adoptions. The planned activities include particulate-matter reductions, toxic-air-contaminant controls, New Source Review changes, and additional monitoring requirements.
This is important for industrial facilities because testing programs designed around yesterday’s requirements may not automatically address tomorrow’s requirements.
2. Particulate Matter Continues to Receive Attention
South Coast AQMD’s 2026 public-hearing schedule includes proposed amendments involving PM10 and particulate matter, including proposed amendments to Rule 1157 and other particulate-related rules.
The agency also scheduled consideration of proposed Rule 444.1 and amendments involving Visible Emissions, Particulate Matter – Concentration, and Solid Particulate Matter – Weight.
For facilities with particulate-emitting processes, these developments reinforce the value of maintaining reliable PM testing and documentation.
3. Monitoring Requirements Are Expanding
South Coast AQMD’s 2026 rule forecast includes proposals concerning fenceline monitoring for metal toxic air contaminants and monitoring/sampling for facilities identified as having significant high-risk levels for gaseous toxic air contaminants.
This reflects a broader regulatory direction toward more detailed emissions information and greater visibility into facility impacts.
4. Air-Quality Conditions Continue to Drive Regulatory Attention
South Coast AQMD’s 2026 news releases have included ozone advisories, particle-pollution advisories, wildfire-smoke advisories, and windblown-dust advisories. In July 2026, for example, the agency issued an ozone advisory associated with a heat wave.
These events don’t mean every industrial facility must automatically perform a particular emissions test. However, they demonstrate why California continues to prioritize air-quality management and emissions-control programs.
EPA’s current guidance explains that implementation of ozone and particulate-matter standards relies on programs including air-quality monitoring, modeling, emissions inventories, and emission-control strategies.
For industrial facilities, reliable source-level emissions information can therefore become an important component of the broader regulatory picture.
Pros of Professional Air Emissions Testing
1. Stronger Regulatory Compliance
Testing provides measurable evidence that an emission source is operating within applicable permit and regulatory requirements.
Rather than relying solely on assumptions or operating conditions, facilities can use documented test results to demonstrate actual performance.
2. Better Emissions Data
Properly designed testing provides traceable and technically defensible emissions data.
This can be particularly important when data is used for:
Permit compliance
Emissions inventories
Regulatory reporting
Engineering evaluations
Corrective actions
Permit renewals
3. Early Identification of Problems
Testing can reveal problems with combustion equipment, pollution-control devices, process conditions, sampling systems, or operating parameters.
Finding a problem early is generally easier than discovering it during an inspection or after a compliance issue develops.
South Coast AQMD states that its inspectors regularly inspect businesses and may issue compliance notices when additional information is required or when minor violations are identified.
4. Improved Process Performance
Emissions testing isn’t only about compliance.
Test results can also help engineers understand how equipment is performing and identify opportunities to improve combustion, pollution-control efficiency, or operating conditions.
That can potentially translate into lower emissions, better efficiency, and improved operational control.
5. Better Inspection Readiness
A facility with organized test protocols, calibration records, field data, QA/QC documentation, laboratory information, calculations, and final reports is generally better prepared when regulators request information.
Cons and Challenges of Air Emissions Testing
Professional testing has significant benefits, but industrial operators should also understand the challenges.
Testing Can Be Expensive
Specialized equipment, qualified personnel, laboratory analysis, engineering support, and reporting can increase project costs.
Production Scheduling Can Be Difficult
Some tests must occur during representative operating conditions, which means production schedules may need to be coordinated around the testing event.
Testing Can Require Specialized Expertise
Different pollutants require different sampling and analytical approaches. Selecting the wrong method or test condition can compromise the usefulness of the results.
Regulations Can Change
California’s regulatory environment is continuously evolving. South Coast AQMD’s 2026 rule calendar itself demonstrates the volume of regulatory activity underway.
Documentation Requirements Can Be Extensive
Testing is not simply about collecting a sample. Facilities may need protocols, calibration information, operating-condition records, QA/QC documentation, calculations, and regulatory reports.
The solution isn’t to avoid testing. The solution is better planning.
What Does a Typical Air Emissions Testing Program Include?
A professional program may include:
Permit and regulatory review
Test-method selection
Compliance test protocol development
Pre-test coordination
Equipment calibration
On-site source or stack testing
QA/QC verification
Laboratory analysis when applicable
Emissions calculations
Technical report preparation
Regulatory submission support
Corrective-action or engineering recommendations when necessary
CARB maintains published stationary-source test methods for criteria pollutants and toxic air contaminants, while local agencies can establish additional requirements.
How Energy Environmental Solutions, Inc. Helps Industries
Energy Environmental Solutions, Inc. (EES) provides end-to-end environmental compliance support for industrial facilities throughout California.
Our Air Emissions Testing Services Include
Source & Stack Testing Testing of industrial emission sources using applicable EPA, CARB, and local Air District methodologies.
NOx Testing Measurement of nitrogen oxide emissions from combustion and industrial processes.
Particulate Matter Testing Testing for Total PM, PM10, PM2.5, filterable particulate matter, and condensable particulate matter where applicable.
VOC Testing Testing and evaluation of volatile organic compound emissions.
Air Toxics Testing Testing for applicable hazardous air pollutants, metals, hexavalent chromium, dioxins/furans, and other regulated contaminants.
CEMS Services
CEMS Certification
RATA
CGA
QA/QC
Monitoring support
Compliance Test Protocol Development Detailed protocols prepared around applicable permits, regulations, test methods, sampling requirements, and operating conditions.
Engineering Studies Technical assessments designed to support emissions compliance, equipment performance, and regulatory decision-making.
Compliance Reporting Clear, organized, inspection-ready reports with supporting technical documentation.
Why Choose EES?
When emissions compliance is on the line, facilities need more than a test result. They need confidence in the entire testing process.
EES helps clients with:
✔ Experienced environmental professionals
✔ EPA & California regulatory expertise
✔ Source and stack testing
✔ Accurate emissions measurements
✔ Customized test protocols
✔ Comprehensive QA/QC
✔ CEMS, RATA & CGA support
✔ Engineering assistance
✔ Compliance reporting
✔ Responsive technical support
✔ Inspection-ready documentation
✔ End-to-end project management
Industries EES Serves
EES supports emissions compliance programs for industries including:
Petroleum Refineries
Power Generation
Chemical Manufacturing
Cement Manufacturing
Manufacturing Facilities
Food Processing
Pharmaceutical Manufacturing
Waste-to-Energy
Industrial Boilers
Metal Processing
Aerospace
Municipal Utilities
Fuel and Petroleum Operations
Partner With EES for California Air Emissions Testing
California’s 2026 regulatory environment demonstrates a continuing emphasis on emissions reductions, monitoring, source testing, particulate matter, toxic air contaminants, and defensible environmental data. South Coast AQMD’s current rulemaking activity includes particulate-matter controls, toxic-air monitoring, and other measures designed to support state and federal air-quality objectives.
For industrial facilities, proactive emissions testing can turn compliance from a reactive exercise into a planned process.
Whether you need Air Emissions Testing, Source Testing, Stack Testing, NOx Testing, PM10/PM2.5 Testing, VOC Testing, Air Toxics Testing, CEMS Certification, RATA, CGA, Compliance Test Protocol Development, Engineering Studies, or Compliance Reporting, Energy Environmental Solutions, Inc. can help you plan, test, document, and respond with confidence.
Don’t wait for an inspection to discover a testing or documentation problem.
