5 Colo. Code Regs. § 1001-5-D-X

Current through Register Vol. 48, No. 1, January 10, 2025

Section 5 CCR 1001-5-D-X - Air Quality Limitations

X.A. Ambient Air Increments

X.A.1. The maximum allowable increases over the baseline concentration for sulfur dioxide, PM10, PM2.5 or nitrogen dioxide except as provided in Section VIII.B. of this part, are:

X.A.1.a. For any Class I area:

PM2.5 (µg/m3)
Annual arithmetic mean	1
Twenty-four hour maximum	2
PM10 (µg/m3)
Annual arithmetic mean	4
Twenty-four hour maximum	8
Sulfur dioxide (µg/m3)
Annual arithmetic mean	2
Twenty-four hour maximum	5
Three hour maximum	25
Nitrogen dioxide (µg/m3)
Annual arithmetic mean	2.5

X.A.1.b. For any Class II area:

PM2.5 (µg/m3)
Annual arithmetic mean	4
Twenty-four hour maximum	9
PM10 (µg/m3)
Annual arithmetic mean	17
Twenty-four hour maximum	30
Sulfur dioxide (µg/m3)
Annual arithmetic mean	20
Twenty-four hour maximum	91
Three hour maximum	512
Nitrogen dioxide (µg/m3)
Annual arithmetic mean	25

X.A.1.c. For any Class III area:

PM2.5 (µg/m3)
Annual arithmetic mean	8
Twenty-four hour maximum	18
PM10 (µg/m3)
Annual arithmetic mean	34
Twenty-four hour maximum	60
Sulfur dioxide (µg/m3)
Annual arithmetic mean	40
Twenty-four hour maximum	182
Three hour maximum	700
Nitrogen dioxide (µg/m3)
Annual arithmetic mean	50

X.A.2. The maximum allowable increases over the baseline concentration for any other air pollutant shall be the same as those increases established pursuant to Section 165(a) of the Federal Act.

X.A.3. For any period, other than an annual period, the applicable maximum allowable increase may be exceeded during one such period per year at any one location.

X.A.4. Periodic Review

X.A.4.a. The Division shall, on a periodic basis, review the adequacy of this Regulation Number 3 for preventing significant deterioration of air quality. Within thirty days after any information becomes available and there is cause to believe that an applicable increment is being violated, the Division shall present the cause for such belief to the Commission.

X.A.4.b. If the Commission concurs that there is cause to believe that an increment is being violated, it shall hold a hearing to determine whether an increment violation exists. The hearing shall be held pursuant to the procedures of Colorado Revised Statute Section 25-7-119. Notice should be given by first class mail to permitted sources that can be reasonably identified as emitting the pollutant in violation and affecting the area of violation.

X.A.4.c. Should the Commission determine that an increment violation exists, the Division shall review all sources affecting the area of increment violation and ensure that all such sources comply with all applicable permit conditions, and state and local regulations. Within thirty days after completing such a review, the Division shall recommend revisions, if necessary, to the Commission to correct the violation. Upon receipt of recommended revisions from the Division, the Commission shall as soon as practicable act to revise this regulation as it deems necessary.

X.A.5. Increment Consumption Restriction

X.A.5.a. No new major stationary source or major modification shall individually consume more than seventy-five percent of an applicable increment.

X.A.5.a.(i) Applicants may request a hearing before the Commission to request a waiver of this restriction. The hearing shall be heard in accordance with the provisions of Colorado Revised Statute Sections 25-7-114 (4)(h), 25-7-119 (Colorado Air Pollution Prevention and Control Act), and Colorado Revised Statute 24-4-105 (State Administrative Procedure Act).

X.A.5.a.(i)(A) The Commission shall not set a hearing date for a waiver request until submittal of comments, or evidence of an opportunity for submittal of comments by all appropriate regional planning agencies and councils of government organizations, affected municipalities and other affected political subdivisions has occurred.

X.A.5.a.(i)(B) Ambient Air Limits. No concentrations of a pollutant shall exceed a national ambient air quality standard or a state ambient air standard where no national ambient air quality standard has been established.

5 CCR 1001-5-D-X

37 CR 18, September 25, 2014, effective 10/15/2014

37 CR 24, December 25, 2014, effective 1/14/2015

39 CR 04, February 25, 2016, effective 3/16/2016

39 CR 21, November 10, 2016, effective 11/30/2016

41 CR 21, November 10, 2018, effective 11/30/2018

43 CR 02, January 25, 2020, effective 2/14/2020

44 CR 02, January 25, 2021, effective 2/14/2021

46 CR 02, January 25, 2022, effective 2/14/2023

46 CR 12, June 25, 2023, effective 7/15/2023

47 CR 06, March 25, 2024, effective 4/15/2024

47 CR 12, June 25, 2024, effective 7/15/2024