Gaya CapitalU.S. Air Testing
and Compliance
Federal Rollback Risk: What Is Actually at Stake for Air Testing, Monitoring and Compliance Services, 2026–2027
Prepared for environmental engineering and consulting leadership, and for the investors who back them. This report measures how much U.S. air-compliance revenue the Trump 2.0 deregulatory program puts at risk by subsegment, separates what has been finalized from what is only proposed, and sets out how firms should position for 2027.
Source: Gaya Capital estimates.1 Impacts are weighted across five core subsegments, net of state-program offsets, and measured against a no-rollback regulatory baseline. They are not year-over-year growth rates.
Key Takeaways
- The rollback hit the new-mandate layer, not the compliance core. Final federal actions mainly removed future revenue (PM-CEMS installs, CCS compliance, fee-driven methane work). Title V, Part 75 QA/RATA, NSPS/NESHAP periodic testing and state SIP work remain in force.
- Base-case exposure is modest. The compliance-centric core is −3.9% in 2026E and −5.2% in 2027E below a no-rollback baseline after state offsets (federal-only: −6.9% and −9.7%). Service-oriented segments alone are about 1–4% and 1–5% below baseline, net.
- The scenario range is wide and skewed to the downside. Net 2027E impact runs from −1.4% (bull) to −10.3% (bear). Enterprise GHG software drives most of the spread (−3% to −30%) because the GHGRP repeal is still only proposed; RY2025 reports are due October 30, 2026.
- Much of the rollback is timing, not elimination. Extensions, presidential exemptions and state waivers are pushing work into 2027–2028. Onterris cut 2026 revenue guidance to $740–790M partly on "temporary regulatory waivers" for rules that "remain promulgated."
- Offsets are real. The 9.0 µg/m³ PM2.5 NAAQS was upheld, HON fenceline monitoring began July 15, 2026, data-center and turbine permitting is surging, and CA, CO and NM keep their own rules. Reshape the service mix; do not shrink capacity.
Executive Summary
Twenty months into the second Trump administration, the federal deregulatory agenda for stationary-source air programs has moved from announcement to execution.
By September 25, 2026, EPA had finalized repeal of the 2024 MATS amendments (including the PM CEMS requirement),2 rescinded the 2009 greenhouse-gas Endangerment Finding,3 partially repealed the power-plant Carbon Pollution Standards,4 and extended oil-and-gas methane (OOOOb/OOOOc) deadlines by roughly 18 months.5 Congress disapproved the Waste Emissions Charge implementing rule under the Congressional Review Act and delayed the fee itself to 2034.6 Presidential exemptions under Clean Air Act §112(i)(4) have deferred air-toxics compliance for dozens of chemical, sterilizer, taconite and coal facilities.7
For an environmental engineering or consulting firm, the question is not whether this is negative. It is which revenue lines are exposed, by how much, for how long, and what replaces them. Our answer, built subsegment by subsegment, is that the damage is real but narrower than headlines suggest:
New-system capex tied to repealed mandates (PM-CEMS, CCS/CO2 compliance), federal GHG reporting and verification, fee-driven methane programs, and grant-funded community monitoring.
OOOOb/OOOOc LDAR and continuous-monitoring build-outs, HON and EtO work at exempted facilities, and some permit-driven testing covered by temporary waivers. Most of this returns in 2027–2028.
The installed-base compliance cadence (Title V semiannual and annual certifications, Part 75 daily, quarterly and annual QA, NSPS/NESHAP periodic performance tests, refinery fenceline, state SIP and permit conditions), which makes up the majority of air-testing revenue.
New-source permitting and testing for data-center power and gas turbines, PSD modeling under a 9.0 µg/m³ PM2.5 standard, HON fenceline sampling, state GHG disclosure, and export-driven methane measurement.
Scope, Baseline and How to Read the Estimates
Baseline. Every percentage in this report is the estimated change in subsegment revenue demand relative to a counterfactual in which the 2023–2024 federal rules were implemented on their original schedules. The figures are not forecasts of year-over-year growth, and they are not EPA estimates.
2026E vs. 2027E. The 2026E figures reflect only federal actions finalized through September 25, 2026. The 2027E figures add the full-year carryover of those actions plus a risk-weighted allowance for clearly identified pending rulemakings. The largest is the GHGRP reconsideration, with smaller allowances for OOOOb comprehensive reconsideration and HON/EtO amendments.
Federal-only vs. net. "Federal-only" assumes no state response. "Net" credits stricter state and local programs (California's AB 617, MRR, SB 253 and district fenceline rules; Colorado Regulation 7; New Mexico 20.2.50 NMAC; Virginia and Illinois data-center generator rules, and similar) that preserve or replace work in their jurisdictions.
Market weights. To convert percentages into dollars, we weight subsegments with Gaya Capital's 2026E sizing of the compliance-centric U.S. air TICC market (~$9.4B, the midpoint of our $8–11B range). Our framework excludes the North America "LDAR" market-research figures (~$10–11B), which mostly measure pipeline leak-detection hardware rather than compliance services.8 Indoor air quality is shown for completeness but has no measurable federal-rollback exposure.
| Subsegment | What's included | 2026E size ($B) | Weight |
|---|---|---|---|
| LDAR | Method 21 / OGI surveys and repairs, LDAR program management, digital platforms, compliance-grade detection equipment | 1.2 | 13% |
| EMS (CEMS/PEMS + QA) | Analyzers, CEMS/PEMS systems and DAHS, O&M contracts, CGA/linearity, RATAs, ECMPS reporting support | 2.0 | 21% |
| Ambient / fenceline AQM | Regulatory networks (Part 58), refinery and chemical fenceline, community and permit-driven ambient stations | 1.1 | 12% |
| Air compliance services | Stack/source testing, permitting (Title V, PSD/NSR), dispersion modeling, compliance management, air labs | 4.0 | 43% |
| Enterprise air/GHG software | Emissions inventory and GHG reporting SaaS, e-GGRT/CEDRI workflows, verification support modules | 1.1 | 12% |
| Compliance-centric total | 9.4 | 100% | |
| IAQ (broad view only) | Indoor air testing, sensors, filtration and IAQ HVAC services | ~11.0 | n/a |
Source: Gaya Capital estimates triangulated from IBISWorld,9 Grand View Research,10 Polaris Market Research,11 Verdantix12 and BCC Research,13 plus provider-level disclosures. Vendor estimates vary widely, often by 2x for the same nominal scope.
Federal Rollback Tracker (as of September 25, 2026)
The table below separates the rollbacks that are final from those that are proposed, deferred or reversed. This is the most important distinction for underwriting 2027 revenue. Several headline rollbacks from 2025 (PM2.5 NAAQS reconsideration, the PHMSA leak-detection rule) turned out very differently from what the August 2025 consensus assumed.
▼ negative demand effect ▲ positive demand effect ◷ deferral ◆ pending swing factor. Status as of September 25, 2026.
| Rule / program | Original action | 2025–26 action | Status (Sept 25, 2026) | Demand effect |
|---|---|---|---|---|
| MATS 2024 amendments (PM CEMS, fPM 0.010) | May 2024 | Repeal proposed June 2025; final signed Feb 19, 2026 | Final. 2012 MATS reinstated | Negative: PM-CEMS capex and certification14 |
| Power-plant CO2 (§111 Carbon Pollution Standards) | Apr 2024 | Partial repeal signed Sept 14, 2026; supplemental proposal to repeal all GHG standards | Final (partial), effective Nov 16, 2026; comments due Nov 2, 2026 | Negative: CCS and CO2 compliance consulting15 |
| 2009 Endangerment Finding and vehicle GHG standards | 2009 | Rescission final Feb 12, 2026 | Final, effective Apr 20, 2026; challenged by 25 state AGs | Negative: federal GHG work; long-tail legal risk16 |
| GHGRP (40 CFR Part 98) | 2009 | Proposal to remove 46 of 47 categories and suspend Subpart W to RY2034 (Sept 2025) | Proposed, not final. RY2025 reports due Oct 30, 2026 | Largest pending swing factor17 |
| Oil & gas methane NSPS OOOOb / EG OOOOc | Mar 2024 | Interim final rule (July 2025); final extensions; Apr 2026 revisions (~$208M/yr cost relief) | In force with ~18-month extensions. Super Emitter Program from Jan 22, 2027 | Deferral: LDAR and continuous monitoring18 |
| Waste Emissions Charge | Nov 2024 | CRA disapproval Mar 14, 2025; statutory delay to 2034 | Inactive until 2034 | Negative: fee-driven LDAR and measurement19 |
| HON / SOCMI and P&R fenceline | May 2024 | Presidential exemptions (July 2025; ≥20 facilities July 13, 2026) | Fenceline monitoring began July 15, 2026 at non-exempt sites | Positive, capped by exemptions20 |
| EtO commercial sterilizers NESHAP | Apr 2024 | July 2025 exemptions for ~40 of ~90 facilities; amendments proposed early 2026 | Partially in force; reconsideration pending | Deferral: EtO CEMS and testing21 |
| PM2.5 NAAQS (9.0 µg/m³) | Feb 2024 | Reconsideration announced Mar 2025; EPA moved to vacate Nov 2025 | Upheld by D.C. Circuit June 26, 2026. Designations overdue | Positive: PSD modeling, monitoring, SIPs22 |
| Good Neighbor Plan (ozone transport) | Mar 2023 | SCOTUS stay (June 2024); EPA administrative stays | Stayed | Negative: NOx retrofit pull-through23 |
| Combustion turbine NSPS (KKKKa) | Proposed 2024 | Final Jan 15, 2026, incl. "temporary" turbines and a low-use Title V exemption | Final | Positive (volume): initial tests, CEMS/PEMS24 |
| PHMSA gas pipeline leak detection and repair | NPRM May 2023 | Final rule issued Jan 17, 2025, then withdrawn under the regulatory freeze | Never took effect. Dates TBD | Negative vs. prior assumptions25 |
| ECMPS 2.0 (Part 75 reporting) | 2021 plan | Migration began Feb 13, 2026 | Live. Q1 2026 data filed in new format | Positive: DAHS and reporting support26 |
Source: Federal Register, EPA, D.C. Circuit, PHMSA and law-firm summaries as footnoted in each row. Several dates rest on secondary summaries. Confirm against the Federal Register before external distribution.
How Rollbacks Reach the P&L: Seven Transmission Channels
Not all rollbacks hit revenue the same way. For operators, the useful question is which channel a rule change works through, because that decides whether revenue is lost, delayed or merely repriced.
Lost upside (capex + new recurring stream)
Recurring revenue lost (software, verification)
Project revenue lost
Timing shift; catch-up when deadlines hit (2027–28)
Timing shift, lumpy; exemption expiry, renewal risk
Gradual erosion of the discretionary "pull"
Long-tail option value
| Channel | Mechanism | Examples (2025–26) | Revenue character | Recovery path |
|---|---|---|---|---|
| 1. Repeal of new mandates | Removes future obligations before they generate installed-base revenue | MATS PM-CEMS; §111 CCS standards; WEC | Lost upside (capex + new recurring stream) | Only via litigation reversal or a future administration |
| 2. Deadline extensions | Pushes compliance dates out 1–3 years | OOOOb/c (~18 months); GHGRP RY2025 to Oct 30, 2026 | Timing shift | Catch-up when deadlines hit (2027–28) |
| 3. Presidential exemptions / waivers | Facility-specific two-year deferrals under §112(i)(4); temporary state waivers | HON, EtO sterilizers, taconite, coke ovens; waivers cited by Onterris27 | Timing shift, lumpy | Exemption expiry; renewal risk |
| 4. Reporting-scope elimination | Removes a reporting obligation entirely | GHGRP proposal (46 of 47 categories)28 | Recurring revenue lost (software, verification) | State programs; voluntary and export MRV |
| 5. Enforcement intensity | Fewer federal case initiations reduce corrective-action and consent-decree work | EDGI: 14 of 24 enforcement measures at weakest or second-weakest level in 202529 | Gradual erosion of the discretionary "pull" | State enforcement; citizen suits |
| 6. Grant cancellations | Ends federally funded monitoring projects | IRA/ARP community air monitoring and EJ grants; OEJECR eliminated30 | Project revenue lost | State (AB 617) and philanthropic funding |
| 7. Legal-structural | Changes EPA's authority itself | Endangerment rescission; Loper Bright31 | Long-tail option value | Litigation (D.C. Circuit, SCOTUS) |
Source: Gaya Capital analysis.
Channels 2 and 3 account for most of the 2026 volume softness that providers are reporting, and both reverse on a schedule. Channels 1 and 4 cause the permanent damage, and they are concentrated in power-sector hardware and federal GHG reporting. For most consulting and testing firms, deferred work is a backlog-management and pricing problem, not a capacity problem.
Exposure map: rules against subsegments
The matrix below shows where each major federal action reaches the five subsegments. It explains why software and EMS carry the most risk while ambient monitoring and core compliance services are the most insulated.
| Federal action | LDAR | EMS | Ambient / fenceline | Compliance services | GHG software |
|---|---|---|---|---|---|
| MATS 2024 repeal | — | High | — | Medium | — |
| §111 CPS partial repeal | — | Medium | — | Medium | Low |
| Endangerment rescission | Low | — | — | Low | Medium |
| GHGRP reconsideration (pending) | Low | Low | — | Low | High |
| OOOOb/c extensions and revisions | High | Low | Low | Low | Low |
| WEC disapproval / delay | Medium | — | — | — | Medium |
| §112(i)(4) exemptions (HON, EtO, taconite) | Low | Medium | Medium | Medium | — |
| Good Neighbor Plan stay | — | Medium | — | Medium | — |
| Grant cancellations / EPA capacity | — | — | Medium | Low | — |
| PM2.5 NAAQS upheld | — | ▲ Tailwind | ▲ Tailwind | ▲ Tailwind | — |
| Turbine NSPS KKKKa / NSR reform | — | ▲ Tailwind | — | ▲ Tailwind | — |
| Tally | 1 high · 1 med | 1 high · 3 med 2 tailwind | 0 high · 2 med 1 tailwind | 0 high · 4 med 2 tailwind | 1 high · 2 med |
Quantified Impact by Subsegment
Why 2027 generally looks worse than 2026. The first-year effect is cushioned by backlog, services already under contract and installed equipment. The second year adds project cancellations and deferrals, a slower replacement cadence, contract renewals and software seat rationalization. Rule relief first reduces new project pull-through; then deferred capital clears out of backlogs and software renewals reset.32
2026E
2027E
Federal-only impact (2026E → 2027E)
| Subsegment | 2026E | 2026 rationale | 2027E | 2027 rationale |
|---|---|---|---|---|
| LDAR (services + equipment + digital) | −8% | WEC removal and its statutory delay eliminate the main extra cost signal for methane. OOOOb/c deadline extensions and April 2026 revisions (EPA: ~$208M/yr in compliance-cost relief) slow route expansion, equipment upgrades and digital spend. Core surveys and repairs continue.33 | −9% | Full-year carryover of the 2025–26 relief. The Super Emitter Program, starting Jan 22, 2027, preserves remote-detection and follow-up demand. Broader OOOOb/c reconsideration is the main downside risk.34 |
| EMS (CEMS/PEMS + QA/O&M incl. RATA) | −9% | Final MATS repeal (Feb 2026) removes the PM CEMS requirement and the tighter fPM and lignite-mercury limits, eliminating a slice of CEMS hardware and certification demand. Existing Part 75 and legacy MATS QA/O&M continue. | −11% | A full year of lower retrofit and replacement demand weighs on equipment and commissioning. ECMPS 2.0 reporting, RATAs and Part 75 QA hold up a revenue floor, so O&M and testing outperform new-system capex. |
| Ambient / fenceline AQM | −2% | The 9.0 µg/m³ PM2.5 NAAQS survived judicial review. HON fenceline sampling started July 15, 2026. Grant cancellations and overdue designations slow network expansion at the margin.35 | −3% | Downside is limited to delayed designations, HON/EtO exemptions and discretionary upgrades. Core NAAQS networks, state monitoring plans and fenceline programs continue. |
| Air compliance services (testing, permitting/modeling, labs) | −6% | MATS rollback and methane extensions reduce retrofit-linked testing, certification and permitting. The Good Neighbor Plan stay cuts NOx-control pull-through. Temporary waivers deferred some permit-driven tests. Recurring Title V, NESHAP, NSPS and Part 75 work protects the installed base. | −7% | A thinner federal retrofit pipeline and lower equipment turnover reduce associated RATAs, performance tests and commissioning. Mandatory periodic testing, permit certifications and state enforcement keep the decline far below software-like rates. |
| Enterprise air/GHG software (SaaS & reporting) | −10% | The GHGRP rollback is still only proposed, and RY2025 reporting is due Oct 30, 2026. Some customers defer upgrades or cut federal-linked modules, but mandatory reporting is still in force.36 | −25% | Risk-weighted for probable finalization of a broad GHGRP cut, which would drive renewal churn in federal modules. EPA estimates $303M/yr in reporter savings, $256M of it from Subpart W.37 |
| IAQ (broad view only) | 0% | Driven by building operations, occupational health and safety, and owner requirements, not stationary-source rules. | 0% | No material incremental rollback effect. |
Net impact after state-program offsets (2026E → 2027E)
| Subsegment | 2026E | Why it falls less in stricter states | 2027E | Why it falls less in stricter states |
|---|---|---|---|---|
| LDAR | −4% | Colorado Reg 7 and New Mexico 20.2.50 NMAC keep their own frequent LDAR schedules. South Coast AQMD Rule 1173 added OGI and tighter leak monitoring from Jan 1, 2026.38 | −4% | State schedules do not depend on federal OOOOb. California refinery fenceline programs were being amended and expanded in 2026, supporting recurring routes and analytics into 2027. |
| EMS | −6% | Part 75/ECMPS QA and reporting continue. District permit conditions and toxics programs keep extra CEMS testing going in stricter jurisdictions. | −7% | The mix shifts toward O&M/QA and away from new hardware. Virginia and Illinois data-center generator rules add testing demand. |
| Ambient / fenceline AQM | −1% | AB 617 community programs, SCAQMD Rules 1180/1180.1 and BAAQMD 12-15 require continuous fee-funded networks. CARB reported ongoing AB 617 activity in July 2026.39 | −1% | State and community monitoring is structurally recurring (instruments, maintenance, data QA, analytics). |
| Air compliance services | −3% | Recurring Title V/NESHAP/NSPS/Part 75 work plus state and local programs cushion the decline. California programs require monitoring plans, audits, QA and enforcement support. | −4% | Weaker federal project pull-through is partly offset by state SIP cycles and PM2.5-driven PSD modeling. |
| Enterprise air/GHG software | −6% | CARB's Mandatory Reporting Regulation and verifier ecosystem continue. SB 253's first Scope 1–2 reports are due Nov 10, 2026. Several states are expanding their own GHG reporting.40 | −12% | If GHGRP is curtailed, federal churn rises, but California MRR, verification workflows, state disclosure and EU-importer MRV keep a meaningful core.41 |
| IAQ (broad view only) | 0% | Minimal direct exposure. | 0% | No material incremental impact. |
Source: Gaya Capital estimates. "Stricter states" include California, Colorado, New Mexico, New York, New Jersey, Washington, Illinois and Virginia (data-center generators).
Translating percentages into dollars
| Subsegment | 2026E size | Federal 2026E | Net 2026E | Federal 2027E | Net 2027E |
|---|---|---|---|---|---|
| LDAR | $1.2B | −$96M | −$48M | −$108M | −$48M |
| EMS (CEMS/PEMS + QA) | $2.0B | −$180M | −$120M | −$220M | −$140M |
| Ambient / fenceline AQM | $1.1B | −$22M | −$11M | −$33M | −$11M |
| Air compliance services | $4.0B | −$240M | −$120M | −$280M | −$160M |
| Enterprise air/GHG software | $1.1B | −$110M | −$66M | −$275M | −$132M |
| Compliance-centric total | $9.4B | −$648M (−6.9%) | −$365M (−3.9%) | −$916M (−9.7%) | −$491M (−5.2%) |
Source: Gaya Capital estimates. Size × impact. Figures are rounded and assume no change in subsegment weights between 2026 and 2027.
Three conclusions follow from the dollar view:
- State programs recover about 45% of the gross federal hit (about $425M of $916M in 2027E). That is why geography is the single most important variable in a firm's rollback exposure.
- Air compliance services is the largest pool by dollars but the smallest by percentage. A diversified stack-testing and permitting practice faces a mid-single-digit headwind, not a structural break.
- GHG software and EMS hardware together account for about 55% of 2027E net dollars at risk while making up only a third of the market. Firms and investors should concentrate diligence there.
Subsegment Deep Dives
6.1 Air compliance services: the resilient core
Stack and source testing, permitting, dispersion modeling and air labs make up roughly 43% of the compliance-centric market. The rollback has not removed the regulatory triggers for most of this work. Title V permits still require semiannual monitoring reports and annual compliance certifications. NSPS and NESHAP still require initial and periodic performance tests (Boiler MACT annual, or triennial where results stay at or below 75% of the limit). Part 75 sources still perform RATAs and quarterly linearity checks.42
What changed in 2026 is the marginal project flow. The best public read-through is Onterris (NYSE: ONT, renamed from Montrose Environmental Group on April 21, 2026). On its Q2 2026 call it cut 2026 revenue guidance from $840–900M to $740–790M. Part of the cut reflected "temporary federal and state regulatory waivers" that postponed select air-testing services, even though management stressed that the underlying rules "remain promulgated." Measurement & Analysis segment revenue slipped to $61.1M from $62.8M a year earlier, and segment margin fell to 26.2% from 29.1%.43
Offsets building for 2027: the D.C. Circuit decision upholding the 9.0 µg/m³ PM2.5 standard makes PSD modeling harder wherever background concentrations approach the standard, pushing more projects toward site-specific monitoring and refined inventories.44 The January 2026 turbine NSPS (KKKKa) creates a large volume of initial performance tests for new gas turbines, including "temporary" bridge-power units at data centers.45
Scenario range (net of state offsets): 2026E −1% / −3% / −6% and 2027E −1% / −4% / −7% (bull / base / bear). Federal-only: 2026E −4% / −6% / −9%; 2027E −4% / −7% / −11%.46
What would change our view — Worse
- Waivers roll over into 2027; a broad NSPS/NESHAP "risk and technology review" rollback reduces periodic testing frequency; state agencies cut Title V staff and slow permit issuance.
What would change our view — Better
- Exemptions expire on schedule in 2027–2028 and deferred testing returns; overdue PM2.5 designations are issued under court order; data-center turbine permits convert to construction at scale.
6.2 EMS: CEMS/PEMS hardware plus QA and O&M
EMS carries the most realized damage because the MATS 2024 repeal removed a mandate that would have created a new installed base. EPA's own regulatory impact analysis puts the annualized cost of PM CEMS at roughly $72,000 per EGU (2019$).47 Across the coal fleet, that is revenue that now will not exist, both the upfront installation and certification and the recurring QA/O&M that would have followed. The §111 Carbon Pollution Standards repeal removes a longer-dated CO2 monitoring and CCS verification opportunity.48
The damage stops at new hardware. Existing Part 75 obligations are unchanged and ECMPS 2.0 went live in February 2026, so quarterly electronic reporting, RATAs and DAHS support continue.49 DOE emergency orders under Federal Power Act §202(c) kept several coal units running through 2026, which sustains legacy CEMS service volumes, although the D.C. Circuit limited that authority in September 2026, so this support may fade.50 The subsegment's revenue mix is shifting from hardware toward service. Hardware margins will fall; service-contract margins should hold.
DAHS channel dynamics matter more than ever. Blackstone-backed Alliance Technical Group acquired ESC Spectrum (StackVision) in early 2026, so a national stack-testing competitor now owns a leading Part 75 DAHS franchise installed at many client sites.51 Independent firms should build neutral DAHS partnerships (for example VIM Technologies or CEMTEK) and ECMPS 2.0 reporting expertise.
Scenario range (net): 2026E −3% / −6% / −9% and 2027E −3% / −7% / −11% (bull / base / bear). Federal-only 2027E: −7% / −11% / −15%.52
6.3 LDAR and methane measurement
The federal methane program was weakened three ways: the WEC was disapproved and delayed to 2034, OOOOb/OOOOc deadlines were extended by roughly 18 months, and the April 2026 revisions reduced compliance costs by about $208M per year by EPA's estimate.53 No OOOOb annual report is due before November 30, 2026, and state-plan deadlines under OOOOc move into early 2027. The PHMSA gas-pipeline leak detection and repair rule, which many 2025 models counted as a demand driver, never took legal effect.54
Three federal weakenings
- WEC disapproved and delayed to 2034
- OOOOb/OOOOc deadlines extended ~18 months
- April 2026 revisions: ~$208M/yr compliance-cost relief (EPA)
Three demand sources independent of Washington
- Colorado and New Mexico run their own LDAR programs with frequencies at or above the federal rules55
- EU Methane Regulation importer MRV (nominally from Jan 1, 2027) pushes U.S. LNG and crude exporters toward OGMP 2.0 Level 5 and MiQ-certified measurement, even as Brussels considers a three-year penalty grace period56
- Super Emitter Program starts January 22, 2027, creating remote-detection response work57
The core surveys remain federal law, and these three demand sources do not depend on Washington.
Scenario range (net): 2026E −2% / −4% / −7% and 2027E −1% / −4% / −8% (bull / base / bear). Federal-only 2027E: −5% / −9% / −14%.58
6.4 Ambient and fenceline monitoring
This is the least exposed subsegment. The PM2.5 standard stands. HON fenceline monitoring began July 15, 2026 at non-exempt SOCMI and polymers-and-resins facilities, with two-week sampling periods (~26 per year), laboratory analysis, quarterly CEDRI reporting and root-cause corrective action from 2027.59 The main negatives are the cancellation of IRA/ARP community-monitoring and environmental-justice grants and the presidential exemptions. At least 20 more chemical facilities received two-year exemptions on July 13, 2026, two days before the compliance date.60
California offsets most of the grant damage within its borders: AB 617 community programs, SCAQMD Rules 1180/1180.1 and BAAQMD Rule 12-15 fund continuous refinery and community networks through permit fees rather than federal grants.61 Bay Area AQMD is developing 2026 amendments to Rule 12-15 covering annual inventories and real-time fenceline monitoring.62
Scenario range (net): 2026E +1% / −1% / −3% and 2027E +1% / −1% / −4% (bull / base / bear). Federal-only 2027E: 0% / −3% / −7%.63
6.5 Enterprise air and GHG software
This subsegment has the widest range of outcomes. EPA's September 2025 proposal would end GHGRP reporting for 46 of 47 source categories and suspend Subpart W (oil and gas) reporting until reporting year 2034.64 It has not been finalized. Instead, EPA extended the RY2025 deadline to October 30, 2026.65 Our earlier working estimate (−44% in 2026) assumed finalization. We now treat 2026 as a deferral year (−10% federal, −6% net) and risk-weight 2027 at −25% federal and −12% net.
The net figure depends on how fast state and voluntary demand replaces federal modules. California's SB 253 requires first Scope 1–2 reports by November 10, 2026 (no Scope 3 or assurance in the first cycle). SB 261 climate-risk reporting remains enjoined.66 CARB's Mandatory Reporting Regulation and its accredited-verifier ecosystem are unaffected, and several other states are building their own GHG reporting rules.67
Scenario range (net): 2026E −2% / −6% / −12% and 2027E −3% / −12% / −30% (bull / base / bear). Federal-only 2027E: −8% / −25% / −45%. Our earlier −44% / −51% federal-only estimate is now close to the 2027 bear case rather than the base case.68
Enforcement and EPA Capacity: The Slow-Moving Risk
Rule changes are visible; enforcement erosion is not. The data conflict. EPA's FY2025 annual results report about 8,300 inspections and 2,127 civil case conclusions, which EPA calls the most in nine years, and over $1.2B in penalties and relief. But FY2025 includes almost four months of the prior administration, and conclusions lag initiations. EDGI's calendar-year review found 14 of 24 enforcement measures at their weakest or second-weakest level in 2025, and fewer civil judicial cases launched than under any administration in 20 years.69
Capacity is shrinking, though less than proposed. Congress funded EPA at about $8.82B for FY2026 against a $4.16B request, but the Office of Research and Development was eliminated and the environmental-justice office closed.70 For the air-testing market this matters in two ways: fewer federal audits of stack-test quality, and slower promulgation of new test methods (PFAS air methods OTM-45 and OTM-50 are the obvious example).
History says deferrable, not eliminable
Two earlier episodes are instructive, but the evidence should be quoted precisely. The Environmental Integrity Project found that EPA civil inspections averaged 46% below their 2002–2017 level during FY2018–2021 (10,110 vs. 18,755 per year).71 EDGI documented 40% fewer stack tests (~2,000) in March–April 2020 than in the same months of 2019.72 EDGI did not document a subsequent catch-up, and our earlier draft's claim of one should not be repeated without a separate source. What the record does support is that permit-mandated testing continued through both episodes and never approached zero. Waivers and weak enforcement delay the work; they do not remove the permit condition.
State Offsets: Where Demand Is Protected
The federal rollback has produced a two-track market. The table ranks the state programs that matter most for air-testing and compliance demand.
| State / program | What it requires | Subsegments supported | 2026–27 status |
|---|---|---|---|
| California: AB 617, CARB MRR/CTR, SB 253 | Community monitoring and emissions-reduction plans; mandatory GHG and criteria/toxics reporting with third-party verification; corporate Scope 1–2 disclosure | Ambient AQM, GHG software, compliance services | AB 617 progress report July 2026; SB 253 first reports Nov 10, 2026 |
| California air districts: SCAQMD 1173, 1180/1180.1; BAAQMD 12-15 | OGI leak monitoring; real-time refinery fenceline and community monitoring; refinery emissions tracking | LDAR, ambient/fenceline | Rule 1173 OGI from Jan 1, 2026; 1180 amendments in development |
| Colorado: Regulation 7 and GHG intensity rules | Frequent LDAR and continuous monitoring for oil and gas; intensity verification | LDAR, GHG software | In force; independent of OOOOb |
| New Mexico: 20.2.50 NMAC | Ozone-precursor LDAR and equipment standards for oil and gas | LDAR | In force |
| Virginia: DEQ APG-576 | Presumptive BACT and performance testing for data-center generators; Tier 4-equivalent expectations from July 1, 2026 | Compliance services, EMS | Revised effective Apr 9, 202673 |
| Illinois: data-center generator rules | Tier 4 for many new diesel emergency generators | Compliance services | Applications from Dec 1, 2026 |
| Texas and Louisiana (volume, not stringency) | HON facilities, LNG terminals, petrochemicals, gas turbines | All core subsegments | Largest absolute testing and permitting volume |
Source: CARB,74 SCAQMD,75 BAAQMD,76 New Mexico Environment Department,77 Virginia DEQ and law-firm summaries.78
Offsetting Tailwinds Outside the Rollback Baseline
Our impact estimates do not net off demand growth unrelated to the rollback. For planning, firms should put the following next to the rollback numbers:
Data-center and bridge power
New gas turbines, reciprocating engines and backup generators need PSD or minor-source permits, BACT analyses, modeling, initial performance tests and CEMS/PEMS. KKKKa's treatment of "temporary" turbines is directly relevant to projects waiting on grid interconnection, and litigation over unpermitted turbine fleets (the NAACP's April 2026 suit over xAI's Southaven, Mississippi turbines) shows that shortcuts create their own consulting work.7980
NSR "begin actual construction" reform
EPA guidance (2025) and a May 13, 2026 proposed rule would let more site work start before permits issue.81 That speeds project schedules and compresses permitting timelines, which rewards firms that can staff quickly.
PM2.5 at 9.0 µg/m³
Harder PSD demonstrations and eventual nonattainment designations mean more modeling, monitoring and SIP work.82
HON fenceline
A new recurring sampling, lab and data-management stream started in July 2026, and exempted facilities return in 2027–2028.
Export and voluntary methane MRV
EU importer requirements, OGMP 2.0 and MiQ certification keep measurement-based methane inventories funded without federal Subpart W.83
LNG, fabs, battery plants and reshoring
Large new sources across the Gulf Coast, Arizona, Ohio and Georgia carry full permitting and testing lifecycles.
Bull / Base / Bear Scenarios, 2026E–2027E
We run three scenarios so that proposed federal actions are not treated as final. The spread is widest for enterprise air/GHG software because that outcome depends most on the pending GHGRP rulemaking.84
Bull (less downside)
Final 2026 rollbacks remain, but further federal reconsiderations are delayed, narrowed or litigated. PM2.5 implementation continues. State and local mandates and industrial activity absorb more of the lost federal pull-through.
Commercial read-through: Higher recurring mix; better capex conversion; limited software churn
Base
Realized 2025–26 federal actions persist. Some additional relief occurs, but broad programs are not fully dismantled. Backlog normalization and lower retrofit intensity become more visible in 2027.
Commercial read-through: Most likely planning case for market sizing; recurring compliance is the floor
Bear (more downside)
Broader OOOOb/c relief and the GHGRP rollback are finalized. PM2.5 implementation weakens materially. Federal project pipelines and compliance-software renewals retrench faster than state programs can offset.
Commercial read-through: Most exposed: new equipment, project-linked testing, federal GHG software
Source: Gaya Capital scenario framework.85
Table A. Federal-only rollback sensitivity
| Subsegment | 2026E Bull | 2026E Base | 2026E Bear | 2027E Bull | 2027E Base | 2027E Bear |
|---|---|---|---|---|---|---|
| LDAR services, equipment & digital | −5% | −8% | −11% | −5% | −9% | −14% |
| EMS / CEMS / PEMS + QA / RATA | −6% | −9% | −12% | −7% | −11% | −15% |
| Outdoor / ambient AQM | 0% | −2% | −5% | 0% | −3% | −7% |
| Air compliance services (testing, permitting, modeling, labs) | −4% | −6% | −9% | −4% | −7% | −11% |
| Enterprise air / GHG software | −5% | −10% | −18% | −8% | −25% | −45% |
| IAQ (broad view) | +1% | 0% | −1% | +1% | 0% | −2% |
| Weighted core (ex-IAQ) | −4.2% | −6.9% | −10.5% | −4.8% | −9.7% | −15.7% |
Source: Gaya Capital estimates.86 The base case includes the February 2026 MATS repeal,87 the April 2026 OOOOb/c technical revisions,88 WEC relief and continued Good Neighbor Plan constraints, and treats broader GHGRP and other reconsiderations as pending.89 Weighted core uses the 2026E subsegment sizes in Section 2.
Table B. U.S. impact after state and recurring-demand offsets
| Subsegment | 2026E Bull | 2026E Base | 2026E Bear | 2027E Bull | 2027E Base | 2027E Bear |
|---|---|---|---|---|---|---|
| LDAR services, equipment & digital | −2% | −4% | −7% | −1% | −4% | −8% |
| EMS / CEMS / PEMS + QA / RATA | −3% | −6% | −9% | −3% | −7% | −11% |
| Outdoor / ambient AQM | +1% | −1% | −3% | +1% | −1% | −4% |
| Air compliance services (testing, permitting, modeling, labs) | −1% | −3% | −6% | −1% | −4% | −7% |
| Enterprise air / GHG software | −2% | −6% | −12% | −3% | −12% | −30% |
| IAQ (broad view) | +1% | 0% | −1% | +1% | 0% | −1% |
| Weighted core (ex-IAQ) | −1.4% | −3.9% | −7.1% | −1.4% | −5.2% | −10.3% |
| Net revenue at risk | −$135M | −$365M | −$669M | −$134M | −$491M | −$970M |
Source: Gaya Capital estimates.90 State offsets are strongest in California and other jurisdictions with their own LDAR, fenceline, criteria/toxics reporting and community-air programs.919293 They do not fully replace lost federal project pull-through, particularly for power-sector CEMS capex or federal-specific GHG software.
2026E (net of state offsets)
2027E (net of state offsets)
Reading the scenarios. The bull case is nearly flat from 2026 to 2027 (−1.4% net in both years), because it assumes deferred work returns as exemptions and waivers lapse. The bear case deepens sharply (−7.1% to −10.3% net) and is dominated by software: at −30%, enterprise GHG software alone accounts for about a third of the bear-case dollars at risk. If each case is given a judgmental weight (25% bull / 50% base / 25% bear), the probability-weighted net impact is about −4.1% in 2026E and −5.6% in 2027E.
Higher for the realized 2026 MATS and technical methane-rule effects; medium for 2027 testing and EMS normalization; lower for 2027 software, which depends on the pending GHGRP rulemaking and on customer retention.
Signpost calendar
What Capital Markets Are Saying
Private capital is still paying premium prices for air-testing platforms in the middle of the rollback. We read that as a sign that sophisticated buyers see the damage as cyclical and contained:
Blackstone Energy Transition Partners acquired Alliance Technical Group
From Morgan Stanley Capital Partners. Alliance has since added ESC Spectrum (DAHS), several labs, Grace Consulting and Atlas's LDAR assets.101
Veritas Capital agreed to acquire Trinity Consultants
From Oak Hill Capital (announced Aug 2026, expected to close by Q4 2026), with Oak Hill reinvesting as a minority holder.102
Onterris launched a board strategic review
After its guidance cut, making the largest listed pure-play a potential take-private or sale candidate.103
Sector deal flow rose
Industrial and environmental services M&A volume increased about 28% year over year, and PE-sponsored middle-market deals averaged about 7.2–7.5x EBITDA. Scaled compliance-testing platforms trade well above that; small, owner-dependent consultancies trade below it.104
Strategic Implications
Rollback sensitivity by business model
| Business model | Rollback sensitivity | 2026–27 implication |
|---|---|---|
| Testing / inspection providers | Most defensible exposure | Installed-base recurring tests, RATAs, permit support and state/local enforcement work should hold up better than project-linked commissioning. Diversification across states and end markets becomes more valuable. |
| CEMS / instrumentation OEMs | Higher cyclicality | New hardware and retrofit systems bear more rollback risk; aftermarket service, calibration, QA and data integration become strategically more important. |
| LDAR technology / services | Mixed | Federal expansion slows, but strong state programs preserve demand. Providers with OGI, continuous monitoring, analytics and multi-jurisdiction capability are better positioned. |
| Ambient / fenceline monitoring | Relatively resilient | Federal uncertainty is offset by state and community programs, refinery fenceline requirements and ongoing network needs. |
| Air / GHG compliance software | Highest policy beta | Federal-specific GHGRP modules face the largest 2027 downside. Broader EHS, state reporting, audit trail, verification and operational-emissions functions reduce churn risk. |
| Engineering / permitting consultancies | Moderate policy beta | Fewer federal retrofit projects are a headwind, but industrial investment, new-source permitting, SIP and state programs, and recurring compliance work remain meaningful offsets. |
Source: Gaya Capital analysis.105
For environmental engineering and consulting firms
- Audit your own rollback exposure by channel. Classify every 2026 backlog line as lost (repealed mandate), deferred (extension or exemption), or intact. Our base case implies that a typical diversified air practice has 4–6% of revenue in the first two buckets, but a GHG- or power-hardware-heavy practice can have 15–25%.
- Build a "deferral calendar" and sell against it. HON, EtO, taconite and coke-oven exemptions expire in 2027–2028; OOOOc state plans land in early 2027; the Super Emitter Program starts January 22, 2027. Put every exempted facility in your territory on a dated pursuit list now. The catch-up will be compressed and crews will be scarce.
- Lead with a power permitting-plus-testing bundle. Combine KKKKa applicability, BACT and Tier 4 strategy (Virginia, Illinois), PSD modeling under the 9.0 µg/m³ standard, initial performance testing and CEMS/PEMS commissioning for data-center and bridge-power developers. This is the largest growth pool, and federal GHG deregulation barely touches it.
- Turn the GHG practice toward state and export demand. Move capacity from federal Subpart W and GHGRP work to California SB 253 and MRR verification, state GHG programs, OGMP 2.0 and MiQ measurement, and EU-importer MRV support. Plan as if the GHGRP proposal will be finalized; treat its survival as upside.
- Sell regulatory-uncertainty advisory as its own service. Clients face rules that may snap back through litigation (the Endangerment Finding, PM2.5 designations, HON/EtO exemptions). Scenario-based compliance planning (what to build now versus defer, and how to preserve permit flexibility) is a billable service that grows with uncertainty.
- Protect field capacity and pricing. Do not cut QSTI/QSTO-qualified crews into a temporary lull that precedes a compressed catch-up. Cross-train stack-testing staff for fenceline and lab work, add cancellation and rescheduling terms to MSAs, and price complex methods (M5/202, HCl, EtO, PFAS OTM-45) on availability.
- Neutralize DAHS channel risk. Where clients run DAHS owned by a competitor, build independent ECMPS 2.0 reporting capability and partnerships with the remaining independent DAHS vendors.
- Weight business development toward protected geographies. Prioritize California, Colorado and New Mexico (state-mandated), Texas and Louisiana (volume: HON, LNG, turbines), and Virginia, Illinois, Ohio, Georgia and Arizona (data centers and fabs).
For investors and sponsors
Underwrite 2027 revenue by channel, not by headline. Discount lost-mandate revenue, time-shift deferred revenue into 2027–2028, and keep installed-base recurring revenue at close to full value.
Use GHG-software and PM-CEMS exposure as a valuation lever. Businesses concentrated there are where buyers are securing price discounts and earn-outs.
Favor platforms with state-program density and new-source permitting depth. They carry the lowest net exposure (about −1% to −4%) and the most direct links to the data-center power cycle.
Revisions, Methodology and Glossary
Appendix A. Revisions to Earlier Gaya Estimates
An earlier Gaya working estimate treated the MATS repeal and GHGRP elimination as proposals likely to become final and assumed a 2026 PM2.5 reconsideration. The table reconciles that version with this report.
| Subsegment | Earlier federal 26/27 | Current federal 26/27 | Earlier net 26/27 | Current net 26/27 | Reason for change |
|---|---|---|---|---|---|
| LDAR | −6% / −7% | −8% / −9% | −3% / −4% | −4% / −4% | April 2026 OOOOb/c revisions (~$208M/yr relief); PHMSA rule never effective |
| EMS | −6% / −9% | −9% / −11% | −4% / −7% | −6% / −7% | MATS repeal finalized Feb 2026 (PM CEMS removed) |
| Ambient / fenceline | −4% / −6% | −2% / −3% | −2% / −3% | −1% / −1% | PM2.5 NAAQS upheld June 26, 2026; HON fenceline began July 15, 2026 |
| Compliance services | −5% / −6% | −6% / −7% | −3% / −4% | −3% / −4% | Realized MATS rollback; waivers deferring tests |
| GHG software | −44% / −51% | −10% / −25% | −38% / −44% | −6% / −12% | GHGRP still only proposed; RY2025 reporting due Oct 30, 2026 |
| IAQ | −1% / −2% | 0% / 0% | 0% / −1% | 0% / 0% | No federal stationary-source link |
Source: Gaya Capital estimates.106 The earlier −44% / −51% federal-only software case now sits near the 2027 bear case (−45%).
What changed versus the prior research case
| Topic | Prior research datapoint | 2026 update / implication |
|---|---|---|
| MATS: proposal → realized rollback | Prior research assumed a rollback proposal; EPA finalized repeal in February 2026, including removal of the PM-CEMS requirement. | Raises confidence in the EMS/CEMS downside and moves some 2027 risk into 2026 realized impact.107 |
| GHGRP: severe downside remains contingent | Prior research assumed rapid cancellation of federal-linked SaaS modules. | Broad GHGRP elimination remains proposed and RY2025 reporting was extended, so the prior −44% / −51% case is now framed as a bear outcome.108 |
| PM2.5: standard still supports monitoring | Prior case assumed greater near-term implementation flexibility. | The 9.0 µg/m³ annual standard remains operative and was upheld by the D.C. Circuit, supporting a smaller base-case haircut to AQM.109 |
| State/local offset has strengthened | Prior analysis correctly identified CA/CO/NM as buffers. | 2026 activity confirms ongoing AB 617 and refinery fenceline implementation; South Coast and Bay Area rule activity supports recurring instruments, O&M and QA.110 |
| Recurring compliance floor remains intact | Prior work emphasized Title V/NESHAP and Part 75 cadence. | EPA systems still require semiannual and annual Title V reports and ECMPS/QA workflows, making service revenue more resilient than new-system capex.111 |
Appendix B. Methodology
- Impact percentages are Gaya Capital estimates of revenue demand relative to a no-rollback regulatory baseline. They are built bottom-up from the revenue channels each rule touches (new-system capex, recurring QA/O&M, periodic testing, reporting, program management), scaled by the share of each subsegment's revenue exposed to that rule, and adjusted for timing (lost vs. deferred).
- State offsets estimate the share of the federal hit that is replaced or protected by state and local programs, weighted by each state's share of regulated sources in the subsegment.
- Dollar figures multiply percentage impacts by Gaya's 2026E subsegment sizes (compliance-centric core ~$9.4B, midpoint of an $8–11B range). Vendor market-research figures were not re-verified at their 2025/2026 editions and vary widely among vendors.
- The 2027E figures are risk-weighted. They distinguish final rules from proposals still subject to rulemaking and litigation. Scenario probabilities are judgmental.
- Key monitoring items: final GHGRP action; broader OOOOb/c reconsideration; PM2.5 designations and any further reconsideration; Good Neighbor Plan litigation and replacement actions; state refinery and fenceline rule amendments; AB 617 funding cadence; power-sector replacement capex; and evidence of software churn versus migration to state or voluntary workflows.
- Not yet incorporated: current labor-market data (QSTI/QSTO headcount, technician wages) and 2026 market pricing for RATAs, OGI surveys and consultant billing rates. We recommend collecting both before these estimates are used for valuation.
Appendix C. Glossary
| Term | Definition |
|---|---|
| BACT | Best Available Control Technology, required for new or modified major sources under PSD. |
| CEDRI | EPA's Compliance and Emissions Data Reporting Interface, used for NESHAP/NSPS reports including HON fenceline data. |
| CEMS / PEMS | Continuous / Predictive Emission Monitoring Systems: instrument-based or model-based stack emissions measurement. |
| CRA | Congressional Review Act: lets Congress nullify recently issued federal rules. |
| DAHS | Data Acquisition and Handling System: software that records and reports CEMS data. |
| ECMPS 2.0 | EPA's Emissions Collection and Monitoring Plan System for Part 75 quarterly reporting. Migration began Feb 2026. |
| GHGRP / e-GGRT | Greenhouse Gas Reporting Program (40 CFR Part 98) and its electronic reporting tool. |
| HON | Hazardous Organic NESHAP for synthetic organic chemical manufacturing (SOCMI). The 2024 amendments added fenceline monitoring. |
| KKKKa | 2026 NSPS subpart for new stationary combustion turbines. |
| LDAR / OGI | Leak Detection and Repair; Optical Gas Imaging (infrared camera leak detection). |
| MATS | Mercury and Air Toxics Standards for power plants. The 2024 amendments were repealed in Feb 2026. |
| NAAQS / SIP | National Ambient Air Quality Standards; State Implementation Plans to meet them. |
| NESHAP / NSPS | National Emission Standards for Hazardous Air Pollutants (40 CFR 63); New Source Performance Standards (40 CFR 60). |
| OOOOb / OOOOc | EPA methane standards for new (OOOOb) and existing (OOOOc, via state plans) oil and gas sources. |
| PSD / NSR | Prevention of Significant Deterioration / New Source Review preconstruction permitting. |
| QSTI / QSTO | Qualified Source Testing Individual / Observer credentials for stack-testing personnel. |
| RATA | Relative Accuracy Test Audit: periodic comparison of a CEMS against reference methods. |
| §112(i)(4) | Clean Air Act provision allowing the President to exempt sources from NESHAP compliance for up to two years. |
| Title V | Clean Air Act operating permit program (40 CFR 70): semiannual monitoring reports and annual compliance certifications. |
| WEC | Waste Emissions Charge: the IRA methane fee, disapproved via CRA in 2025 and delayed to 2034. |
For more information on our research and detailed methodology, please visit www.gayacapital.com.
Sources
Numbered footnotes correspond to superscripts in the text. Links open the cited source in a new tab; ↩ returns to the first citation.
- 1.Gaya Capital, "U.S. Air Testing & Compliance: 2026E–2027E Regulatory Rollback Risk — Bull / Base / Bear Scenario Analysis" (Sept. 25, 2026). ↩
- 2.U.S. EPA, "National Emission Standards for Hazardous Air Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units — Repeal of Amendments," 91 Fed. Reg. (Feb. 24, 2026), federalregister.gov; EPA, MATS final repeal fact sheet (Feb. 2026), epa.gov. ↩
- 3.U.S. EPA, "Rescission of the Greenhouse Gas Endangerment Finding and Motor Vehicle Greenhouse Gas Emission Standards," 91 Fed. Reg. (Feb. 18, 2026), federalregister.gov; State Impact Center, "Twenty-Five AGs Filed Lawsuit Challenging EPA's Endangerment Finding Repeal," stateimpactcenter.org. ↩
- 4.U.S. EPA, "Partial Repeal of the Carbon Pollution Standards for Fossil Fuel-Fired Electric Generating Units," 91 Fed. Reg. (Sept. 17, 2026), federalregister.gov; National Law Review, "EPA Repeals Power Plant Carbon Pollution Standards and Proposes to Repeal All Power Plant Greenhouse Gas Emissions Standards" (Sept. 2026). ↩
- 5.U.S. EPA, "2025 Interim Final Rule to Extend Compliance Deadlines," epa.gov; ALL4, "U.S. EPA Finalizes Oil and Gas Compliance Deadline Extension" (2025). ↩
- 6.U.S. EPA, "Methane Emissions Reduction Program" (WEC disapproval under the Congressional Review Act, Mar. 14, 2025), epa.gov; Congressional Research Service, IF13191, congress.gov. ↩
- 7.Louisville Public Media, "Pair of Kentucky chemical plants exempted from EPA rule meant to reduce harmful emissions" (July 22, 2026), lpm.org (at least 20 facilities granted two-year exemptions on July 13, 2026); Manufacturing Dive, "Trump approves emissions exemptions for some chemical, taconite iron ore facilities" (July 2025). ↩
- 8.Grand View Research, "North America Leak Detection and Repair Market Size & Outlook," grandviewresearch.com ($10.96B in 2023); Acumen Research and Consulting, LDAR market report (~$10.03B North America, 2023). ↩
- 9.IBISWorld, "Water & Air Quality Testing Services in the US" (2025 edition), ibisworld.com (combined U.S. market ~$8.8B; air allocation of 35–55% is a Gaya Capital assumption). ↩
- 10.Grand View Research, "U.S. Emission Monitoring Systems Market Size & Outlook," grandviewresearch.com ($1.13B in 2023; 7.9% CAGR to 2030). ↩
- 11.Polaris Market Research, "U.S. Air Quality Monitoring System Market," polarismarketresearch.com ($1.06B in 2024). ↩
- 12.Verdantix, EHS software market size and forecast, as cited in industry coverage (~$1.8B in 2023 to ~$3.1B in 2028, global). ↩
- 13.BCC Research, "U.S. Indoor Air Quality Market" ($10.5B in 2024; $12.9B projected for 2029). ↩
- 14.U.S. EPA, "National Emission Standards for Hazardous Air Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units — Repeal of Amendments," 91 Fed. Reg. (Feb. 24, 2026), federalregister.gov; EPA, MATS final repeal fact sheet (Feb. 2026), epa.gov. ↩
- 15.U.S. EPA, "Partial Repeal of the Carbon Pollution Standards for Fossil Fuel-Fired Electric Generating Units," 91 Fed. Reg. (Sept. 17, 2026), federalregister.gov; National Law Review, "EPA Repeals Power Plant Carbon Pollution Standards and Proposes to Repeal All Power Plant Greenhouse Gas Emissions Standards" (Sept. 2026). ↩
- 16.U.S. EPA, "Rescission of the Greenhouse Gas Endangerment Finding and Motor Vehicle Greenhouse Gas Emission Standards," 91 Fed. Reg. (Feb. 18, 2026), federalregister.gov; State Impact Center, "Twenty-Five AGs Filed Lawsuit Challenging EPA's Endangerment Finding Repeal," stateimpactcenter.org. ↩
- 17.U.S. EPA, "Reconsideration of the Greenhouse Gas Reporting Program," 90 Fed. Reg. (Sept. 16, 2025), federalregister.gov; EPA fact sheet, epa.gov. ↩
- 18.U.S. EPA, "EPA Continues to Unleash Domestic Energy with Revisions to Burdensome, Unworkable Biden-era Oil and Natural Gas Regulations" (Apr. 6, 2026), epa.gov; EPA, "2026 Final Rule to Reduce Burden on the Oil and Natural Gas Industry." ↩
- 19.U.S. EPA, "Methane Emissions Reduction Program" (WEC disapproval under the Congressional Review Act, Mar. 14, 2025), epa.gov; Congressional Research Service, IF13191, congress.gov. ↩
- 20.Trihydro, "HON Rule Fenceline Monitoring Is a Data Governance Challenge, Not Just a Monitoring Exercise" (2026); RJ Lee Group, "2027 HON Fenceline Compliance Is Here" (2026), rjleegroup.com (existing-source fenceline monitoring effective July 15, 2026). ↩
- 21.U.S. EPA, "EPA Releases Proposal for Commercial Sterilizers to Safeguard Supply of Life-Saving Medical Devices" (2026), epa.gov; ALL4, "U.S. EPA's Proposed Amendments to the Ethylene Oxide Sterilizer Rule" (2026). ↩
- 22.Commonwealth of Kentucky v. EPA, No. 24-1050 (D.C. Cir. June 26, 2026), law.justia.com; ALL4, "D.C. Circuit Upholds Annual PM2.5 NAAQS Revision to 9.0 µg/m³" (2026). ↩
- 23.U.S. EPA, "EPA Response to Judicial Stay Orders" (Good Neighbor Plan), epa.gov. Accessed Sept. 25, 2026. ↩
- 24.U.S. EPA, "Standards of Performance for Stationary Combustion Turbines" (Subpart KKKKa), 91 Fed. Reg. 1910 (Jan. 15, 2026); Clark Hill, "EPA Turbine Rules and Air Permitting for Data Centers" (2026), clarkhill.com. ↩
- 25.American Public Gas Association, "Status Update on the Leak Detection and Repair Final Rule" (Jan. 23, 2025), apga.org; PHMSA, PIPES Act Rulemaking Status Chart (June 2026). ↩
- 26.VIM Technologies, "ECMPS 2.0 Migration Begins Feb. 13: 5 Things You Must Do Before Reporting Starts in Q1 2026," vimtechnologies.com. ↩
- 27.Onterris (formerly Montrose Environmental Group), Q2 2026 earnings call (Aug. 5, 2026), transcript via roic.ai; Business Wire, "Montrose Environmental Group Reports Record Revenue, Earnings and Cash Flow in 2025" (Feb. 25, 2026). ↩
- 28.U.S. EPA, "Rulemaking Notices for GHG Reporting," epa.gov; U.S. EPA, fact sheet on the RY2025 reporting-deadline extension (Feb. 2026), epa.gov. ↩
- 29.U.S. EPA, "Enforcement and Compliance Assurance Annual Results, Fiscal Year 2025," epa.gov; EDGI, "EPA's Enforcement Report and Press Release, Annotated" (Feb. 2, 2026), envirodatagov.org. ↩
- 30.Congressional Research Service, R48575, "U.S. Environmental Protection Agency: FY2026 Appropriations," congress.gov (FY2026 enacted ~$8.82B under P.L. 119-74 vs. $4.16B requested). ↩
- 31.Loper Bright Enterprises v. Raimondo, 603 U.S. 369 (2024) (overruling Chevron U.S.A. v. NRDC). ↩
- 32.Gaya Capital, "U.S. Air Testing & Compliance: 2026E–2027E Regulatory Rollback Risk — Bull / Base / Bear Scenario Analysis" (Sept. 25, 2026). ↩
- 33.U.S. EPA, "EPA Continues to Unleash Domestic Energy with Revisions to Burdensome, Unworkable Biden-era Oil and Natural Gas Regulations" (Apr. 6, 2026), epa.gov; EPA, "2026 Final Rule to Reduce Burden on the Oil and Natural Gas Industry." ↩
- 34.U.S. EPA, "Methane Super Emitter Program," epa.gov (implementation extended to Jan. 22, 2027). Accessed Sept. 25, 2026. ↩
- 35.U.S. EPA, "National Ambient Air Quality Standards (NAAQS) for PM," epa.gov; Harvard EELP Regulatory Tracker, PM NAAQS, eelp.law.harvard.edu. Accessed Sept. 25, 2026. ↩
- 36.U.S. EPA, "Extending the Reporting Deadline Under the Greenhouse Gas Reporting Rule for 2025," 91 Fed. Reg. (Feb. 27, 2026), federalregister.gov. ↩
- 37.U.S. EPA, "EPA Releases Proposal to End Burdensome, Costly Greenhouse Gas Reporting Program" (Sept. 12, 2025), epa.gov. ↩
- 38.South Coast AQMD, "2026 Rule Compliance Deadlines" (Rule 1173 OGI/leak-monitoring requirements effective Jan. 1, 2026); South Coast AQMD, "Rule 1180 — Fenceline Air Monitoring & Refinery Plans"; Bay Area AQMD, "Regulation 12, Rule 15: Petroleum Refining Emissions Tracking — 2026 Amendment." ↩
- 39.California Air Resources Board, "2025 AB 617 CARB Annual Progress Report" (July 2026), ww2.arb.ca.gov; CARB, "Mandatory Reporting of Greenhouse Gas Emissions — 2026 Rulemaking," ww2.arb.ca.gov. ↩
- 40.Mayer Brown, "California Climate Disclosure Laws: CARB Finalizes Its Initial Rulemaking, Resets the 2026 Deadline and Previews the 2027 Framework" (Aug. 2026); Sidley, "SB 253 Update: CARB Delays Reporting Deadline to November 2026" (June 30, 2026). ↩
- 41.Beveridge & Diamond, "With Federal Greenhouse Gas Reporting in Limbo, States Expand GHG Reporting" (2026), bdlaw.com; New Mexico Environment Department, Ozone Precursor Rule 20.2.50 NMAC FAQ. ↩
- 42.U.S. EPA, "CEDRI — List of Rules" (Title V semiannual monitoring and annual compliance certification reports), epa.gov; U.S. EPA, "EPA-Issued Operating Permits," epa.gov. ↩
- 43.Onterris (formerly Montrose Environmental Group), Q2 2026 earnings call (Aug. 5, 2026), transcript via roic.ai; Business Wire, "Montrose Environmental Group Reports Record Revenue, Earnings and Cash Flow in 2025" (Feb. 25, 2026). ↩
- 44.Commonwealth of Kentucky v. EPA, No. 24-1050 (D.C. Cir. June 26, 2026), law.justia.com; ALL4, "D.C. Circuit Upholds Annual PM2.5 NAAQS Revision to 9.0 µg/m³" (2026). ↩
- 45.U.S. EPA, "Standards of Performance for Stationary Combustion Turbines" (Subpart KKKKa), 91 Fed. Reg. 1910 (Jan. 15, 2026); Clark Hill, "EPA Turbine Rules and Air Permitting for Data Centers" (2026), clarkhill.com. ↩
- 46.Gaya Capital, "U.S. Air Testing & Compliance: 2026E–2027E Regulatory Rollback Risk — Bull / Base / Bear Scenario Analysis" (Sept. 25, 2026). ↩
- 47.U.S. EPA, Regulatory Impact Analysis for the Final Repeal of the 2024 MATS Amendments (Feb. 2026), epa.gov. Annualized PM CEMS cost of ~$72,000 per EGU (2019$). ↩
- 48.U.S. EPA, "Partial Repeal of the Carbon Pollution Standards for Fossil Fuel-Fired Electric Generating Units," 91 Fed. Reg. (Sept. 17, 2026), federalregister.gov; National Law Review, "EPA Repeals Power Plant Carbon Pollution Standards and Proposes to Repeal All Power Plant Greenhouse Gas Emissions Standards" (Sept. 2026). ↩
- 49.VIM Technologies, "ECMPS 2.0 Migration Begins Feb. 13: 5 Things You Must Do Before Reporting Starts in Q1 2026," vimtechnologies.com. ↩
- 50.Willkie Farr & Gallagher, "D.C. Circuit Limits DOE's Section 202(c) Emergency Authority to Keep Coal Generator Operational" (Sept. 2026), willkie.com; Utility Dive, "Power plants under DOE emergency orders are producing way less energy than before" (2026), utilitydive.com. ↩
- 51.Blackstone, "Blackstone Energy Transition Partners Announces Acquisition of Alliance Technical Group" (Jan. 6, 2026); Alliance Technical Group, acquisitions news, alliancetg.com. ↩
- 52.U.S. EPA, "ECMPS Reporting Instructions," including 2025–2026 emissions, monitoring-plan, MATS and QA reporting instructions and recurring RATA frequency requirements, epa.gov. ↩
- 53.U.S. EPA, "EPA Continues to Unleash Domestic Energy with Revisions to Burdensome, Unworkable Biden-era Oil and Natural Gas Regulations" (Apr. 6, 2026), epa.gov; EPA, "2026 Final Rule to Reduce Burden on the Oil and Natural Gas Industry." ↩
- 54.American Public Gas Association, "Status Update on the Leak Detection and Repair Final Rule" (Jan. 23, 2025), apga.org; PHMSA, PIPES Act Rulemaking Status Chart (June 2026). ↩
- 55.New Mexico Environment Department, "Compliance and Enforcement — Ozone Precursor Rule" (20.2.50 NMAC), env.nm.gov. ↩
- 56.Oxford Institute for Energy Studies, "EU Methane Import Requirements" (ET44, Mar. 2025); Energy News, "Emmanuel Macron asks Brussels to delay EU methane obligations" (Sept. 2026); IOGP Europe joint statement (June 2026). ↩
- 57.U.S. EPA, "Methane Super Emitter Program," epa.gov (implementation extended to Jan. 22, 2027). Accessed Sept. 25, 2026. ↩
- 58.U.S. EPA, "2026 Final Rule to Reduce Burden on the Oil and Natural Gas Industry" (Apr. 2026; ~$2.5B savings over 2024–2038, ~$208M annually), epa.gov; U.S. EPA, "Actions and Notices about Oil and Natural Gas," epa.gov. ↩
- 59.Trihydro, "HON Rule Fenceline Monitoring Is a Data Governance Challenge, Not Just a Monitoring Exercise" (2026); RJ Lee Group, "2027 HON Fenceline Compliance Is Here" (2026), rjleegroup.com (existing-source fenceline monitoring effective July 15, 2026). ↩
- 60.Louisville Public Media, "Pair of Kentucky chemical plants exempted from EPA rule meant to reduce harmful emissions" (July 22, 2026), lpm.org (at least 20 facilities granted two-year exemptions on July 13, 2026); Manufacturing Dive, "Trump approves emissions exemptions for some chemical, taconite iron ore facilities" (July 2025). ↩
- 61.California Air Resources Board, "2025 AB 617 CARB Annual Progress Report" (July 2026), ww2.arb.ca.gov; CARB, "Mandatory Reporting of Greenhouse Gas Emissions — 2026 Rulemaking," ww2.arb.ca.gov. ↩
- 62.Bay Area AQMD, "Regulation 12, Rule 15: Petroleum Refining Emissions Tracking — 2026 Amendment" (annual inventories and real-time fenceline monitoring), baaqmd.gov. ↩
- 63.California Air Resources Board, "Community Air Monitoring," ww2.arb.ca.gov; South Coast AQMD, "Rule 1180 & Rule 1180.1 Latest Updates," aqmd.gov; South Coast AQMD, "Proposed Amended Rules 1180 and 1180.1," aqmd.gov. ↩
- 64.U.S. EPA, "Reconsideration of the Greenhouse Gas Reporting Program," 90 Fed. Reg. (Sept. 16, 2025), federalregister.gov; EPA fact sheet, epa.gov. ↩
- 65.U.S. EPA, "Extending the Reporting Deadline Under the Greenhouse Gas Reporting Rule for 2025," 91 Fed. Reg. (Feb. 27, 2026), federalregister.gov. ↩
- 66.Mayer Brown, "California Climate Disclosure Laws: CARB Finalizes Its Initial Rulemaking, Resets the 2026 Deadline and Previews the 2027 Framework" (Aug. 2026); Sidley, "SB 253 Update: CARB Delays Reporting Deadline to November 2026" (June 30, 2026). ↩
- 67.Beveridge & Diamond, "With Federal Greenhouse Gas Reporting in Limbo, States Expand GHG Reporting" (2026), bdlaw.com; New Mexico Environment Department, Ozone Precursor Rule 20.2.50 NMAC FAQ. ↩
- 68.U.S. EPA, "Rulemaking Notices for GHG Reporting," epa.gov; U.S. EPA, fact sheet on the RY2025 reporting-deadline extension (Feb. 2026), epa.gov. ↩
- 69.U.S. EPA, "Enforcement and Compliance Assurance Annual Results, Fiscal Year 2025," epa.gov; EDGI, "EPA's Enforcement Report and Press Release, Annotated" (Feb. 2, 2026), envirodatagov.org. ↩
- 70.Congressional Research Service, R48575, "U.S. Environmental Protection Agency: FY2026 Appropriations," congress.gov (FY2026 enacted ~$8.82B under P.L. 119-74 vs. $4.16B requested). ↩
- 71.Environmental Integrity Project, "EPA Enforcement After 20 Years" (Feb. 25, 2022), environmentalintegrity.org. ↩
- 72.EDGI, "More Permission to Pollute: The Decline of EPA Enforcement and Industry Compliance during COVID" (Aug. 13, 2020), envirodatagov.org. ↩
- 73.Greenberg Traurig, "Data Centers and Air Quality: Recent Changes and Important Considerations for Developers" (June 2026); Virginia DEQ, "Issued Air Permits for Data Centers," deq.virginia.gov; Encino Environmental, "States Are Tightening the Rules for Data Center Backup Generators" (2026). ↩
- 74.California Air Resources Board, "2025 AB 617 CARB Annual Progress Report" (July 2026), ww2.arb.ca.gov; CARB, "Mandatory Reporting of Greenhouse Gas Emissions — 2026 Rulemaking," ww2.arb.ca.gov. ↩
- 75.South Coast AQMD, "2026 Rule Compliance Deadlines" (Rule 1173 OGI/leak-monitoring requirements effective Jan. 1, 2026); South Coast AQMD, "Rule 1180 — Fenceline Air Monitoring & Refinery Plans"; Bay Area AQMD, "Regulation 12, Rule 15: Petroleum Refining Emissions Tracking — 2026 Amendment." ↩
- 76.Bay Area AQMD, "Regulation 12, Rule 15: Petroleum Refining Emissions Tracking — 2026 Amendment" (annual inventories and real-time fenceline monitoring), baaqmd.gov. ↩
- 77.New Mexico Environment Department, "Compliance and Enforcement — Ozone Precursor Rule" (20.2.50 NMAC), env.nm.gov. ↩
- 78.Greenberg Traurig, "Data Centers and Air Quality: Recent Changes and Important Considerations for Developers" (June 2026); Virginia DEQ, "Issued Air Permits for Data Centers," deq.virginia.gov; Encino Environmental, "States Are Tightening the Rules for Data Center Backup Generators" (2026). ↩
- 79.U.S. EPA, "Standards of Performance for Stationary Combustion Turbines" (Subpart KKKKa), 91 Fed. Reg. 1910 (Jan. 15, 2026); Clark Hill, "EPA Turbine Rules and Air Permitting for Data Centers" (2026), clarkhill.com. ↩
- 80.Southern Environmental Law Center, "Civil rights group sues xAI for illegal pollution from data center power plant" (Apr. 2026), selc.org; Utility Dive, "DOJ intervenes on behalf of xAI in data center gas turbine lawsuit" (2026), utilitydive.com. ↩
- 81.U.S. EPA, "Begin Actual Construction in the New Source Review (NSR) Preconstruction Permitting Program," proposed rule, 91 Fed. Reg. (May 13, 2026), federalregister.gov. ↩
- 82.Commonwealth of Kentucky v. EPA, No. 24-1050 (D.C. Cir. June 26, 2026), law.justia.com; ALL4, "D.C. Circuit Upholds Annual PM2.5 NAAQS Revision to 9.0 µg/m³" (2026). ↩
- 83.Oxford Institute for Energy Studies, "EU Methane Import Requirements" (ET44, Mar. 2025); Energy News, "Emmanuel Macron asks Brussels to delay EU methane obligations" (Sept. 2026); IOGP Europe joint statement (June 2026). ↩
- 84.Gaya Capital, "U.S. Air Testing & Compliance: 2026E–2027E Regulatory Rollback Risk — Bull / Base / Bear Scenario Analysis" (Sept. 25, 2026). ↩
- 85.Gaya Capital, "U.S. Air Testing & Compliance: 2026E–2027E Regulatory Rollback Risk — Bull / Base / Bear Scenario Analysis" (Sept. 25, 2026). ↩
- 86.Gaya Capital, "U.S. Air Testing & Compliance: 2026E–2027E Regulatory Rollback Risk — Bull / Base / Bear Scenario Analysis" (Sept. 25, 2026). ↩
- 87.U.S. EPA, "Analysis of the Final Repeal of the Mercury and Air Toxics Standards Amendments" (Feb. 2026), epa.gov; U.S. EPA, "Mercury and Air Toxics Standards" rule history, epa.gov. ↩
- 88.U.S. EPA, "2026 Final Rule to Reduce Burden on the Oil and Natural Gas Industry" (Apr. 2026; ~$2.5B savings over 2024–2038, ~$208M annually), epa.gov; U.S. EPA, "Actions and Notices about Oil and Natural Gas," epa.gov. ↩
- 89.U.S. EPA, "Rulemaking Notices for GHG Reporting," epa.gov; U.S. EPA, fact sheet on the RY2025 reporting-deadline extension (Feb. 2026), epa.gov. ↩
- 90.Gaya Capital, "U.S. Air Testing & Compliance: 2026E–2027E Regulatory Rollback Risk — Bull / Base / Bear Scenario Analysis" (Sept. 25, 2026). ↩
- 91.California Air Resources Board, "2025 AB 617 CARB Annual Progress Report" (July 2026), ww2.arb.ca.gov; CARB, "Mandatory Reporting of Greenhouse Gas Emissions — 2026 Rulemaking," ww2.arb.ca.gov. ↩
- 92.South Coast AQMD, "2026 Rule Compliance Deadlines" (Rule 1173 OGI/leak-monitoring requirements effective Jan. 1, 2026); South Coast AQMD, "Rule 1180 — Fenceline Air Monitoring & Refinery Plans"; Bay Area AQMD, "Regulation 12, Rule 15: Petroleum Refining Emissions Tracking — 2026 Amendment." ↩
- 93.New Mexico Environment Department, "Compliance and Enforcement — Ozone Precursor Rule" (20.2.50 NMAC), env.nm.gov. ↩
- 94.SCOTUSblog, "Suncor Energy Inc. v. County Commissioners of Boulder County (No. 25-170)," scotusblog.com; Supreme Court of the United States, October Term 2026 argument calendar. ↩
- 95.U.S. EPA, "Extending the Reporting Deadline Under the Greenhouse Gas Reporting Rule for 2025," 91 Fed. Reg. (Feb. 27, 2026), federalregister.gov. ↩
- 96.U.S. EPA, "Partial Repeal of the Carbon Pollution Standards for Fossil Fuel-Fired Electric Generating Units," 91 Fed. Reg. (Sept. 17, 2026), federalregister.gov; National Law Review, "EPA Repeals Power Plant Carbon Pollution Standards and Proposes to Repeal All Power Plant Greenhouse Gas Emissions Standards" (Sept. 2026). ↩
- 97.Mayer Brown, "California Climate Disclosure Laws: CARB Finalizes Its Initial Rulemaking, Resets the 2026 Deadline and Previews the 2027 Framework" (Aug. 2026); Sidley, "SB 253 Update: CARB Delays Reporting Deadline to November 2026" (June 30, 2026). ↩
- 98.Oxford Institute for Energy Studies, "EU Methane Import Requirements" (ET44, Mar. 2025); Energy News, "Emmanuel Macron asks Brussels to delay EU methane obligations" (Sept. 2026); IOGP Europe joint statement (June 2026). ↩
- 99.U.S. EPA, "Methane Super Emitter Program," epa.gov (implementation extended to Jan. 22, 2027). Accessed Sept. 25, 2026. ↩
- 100.Trihydro, "HON Rule Fenceline Monitoring Is a Data Governance Challenge, Not Just a Monitoring Exercise" (2026); RJ Lee Group, "2027 HON Fenceline Compliance Is Here" (2026), rjleegroup.com (existing-source fenceline monitoring effective July 15, 2026). ↩
- 101.Blackstone, "Blackstone Energy Transition Partners Announces Acquisition of Alliance Technical Group" (Jan. 6, 2026); Alliance Technical Group, acquisitions news, alliancetg.com. ↩
- 102.Business Wire, "Veritas Capital to Acquire Trinity Consultants" (Aug. 5, 2026), businesswire.com. ↩
- 103.Onterris (formerly Montrose Environmental Group), Q2 2026 earnings call (Aug. 5, 2026), transcript via roic.ai; Business Wire, "Montrose Environmental Group Reports Record Revenue, Earnings and Cash Flow in 2025" (Feb. 25, 2026). ↩
- 104.IMAP, "Environmental Consulting Demand Lifts Industrial and Environmental Services M&A" (2026); Capstone Partners, Industrial & Environmental Services M&A Update (2026). ↩
- 105.Gaya Capital, "U.S. Air Testing & Compliance: 2026E–2027E Regulatory Rollback Risk — Bull / Base / Bear Scenario Analysis" (Sept. 25, 2026). ↩
- 106.Gaya Capital, "U.S. Air Testing & Compliance: 2026E–2027E Regulatory Rollback Risk — Bull / Base / Bear Scenario Analysis" (Sept. 25, 2026). ↩
- 107.U.S. EPA, "Analysis of the Final Repeal of the Mercury and Air Toxics Standards Amendments" (Feb. 2026), epa.gov; U.S. EPA, "Mercury and Air Toxics Standards" rule history, epa.gov. ↩
- 108.U.S. EPA, "Rulemaking Notices for GHG Reporting," epa.gov; U.S. EPA, fact sheet on the RY2025 reporting-deadline extension (Feb. 2026), epa.gov. ↩
- 109.U.S. EPA, "National Ambient Air Quality Standards (NAAQS) for PM," epa.gov; Harvard EELP Regulatory Tracker, PM NAAQS, eelp.law.harvard.edu. Accessed Sept. 25, 2026. ↩
- 110.California Air Resources Board, "Community Air Monitoring," ww2.arb.ca.gov; South Coast AQMD, "Rule 1180 & Rule 1180.1 Latest Updates," aqmd.gov; South Coast AQMD, "Proposed Amended Rules 1180 and 1180.1," aqmd.gov. ↩
- 111.U.S. EPA, "CEDRI — List of Rules" (Title V semiannual monitoring and annual compliance certification reports), epa.gov; U.S. EPA, "EPA-Issued Operating Permits," epa.gov. ↩