Air Quality

Colorado Finalizes Landfill Methane Reduction Rule

Posted: March 5th, 2026

Author: Brian Taylor On December 18, 2025, the Colorado Air Quality Control Commission (AQCC) approved the Colorado Department of Public Health and Environment (CDPHE), Air Pollution Control Division’s (Division) proposed rule establishing requirements for methane emissions reductions from municipal solid […]

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Colorado Public Protections From Toxic Air Contaminants

Posted: March 5th, 2026

Author: Clayton Queen Colorado is implementing big changes for facilities emitting toxic air contaminants (TAC). In June 2022, the Colorado State Assembly passed HB22-1244 (Public Protections From Toxic Air Contaminants), which directed Colorado Public Health & Environment (CDPHE) to implement […]

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U.S. EPA Finalizes Combustion Turbine NSPS Revisions

Posted: January 27th, 2026

Author: Caleb Fetner Less than one week after being signed by U.S. Environmental Protection Agency (U.S. EPA) Administrator Lee Zeldin, the Combustion Turbine New Source Performance Standards (NSPS) revisions were published in the Federal Register on January 15, 2026 and […]

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2026 Look Ahead

Posted: January 14th, 2026

2026 Look Ahead Intro // Colin McCall Happy New Year to all of our readers. We are looking forward to another year of work and camaraderie with our colleagues, clients, and partners. In keeping with tradition, we use our January […]

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2026 Air Quality Look Ahead

Posted: January 14th, 2026

Author: Amy Marshall While 2025 brought a new administration and changes to how the United States Environmental Protection Agency (U.S. EPA) approaches air quality regulation and policy, we expect to see even more air quality regulatory activity in 2026. The […]

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U.S. EPA Finalizes Oil and Gas Compliance Deadline Extension

Posted: January 8th, 2026

Author: Ashley Brooks Revisiting Our Previous Update In our earlier blog post, U.S. EPA Extends Compliance Deadlines for Oil and Natural Gas Sector, we discussed the interim final rule (IFR) issued in July 2025 that provided temporary compliance relief under […]

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A Presidential Exemption for the Coke Ovens Rules

Posted: December 4th, 2025

Author: Dustin Snare ALL4 has covered the amendments to the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Coke Ovens: Pushing, Quenching, and Battery Stacks (PQBS) and Coke Oven Batteries (COB) at 40 CFR Part 63, Subparts CCCCC and […]

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