Oklahoma Department of Environmental Quality
2025 Carbon Monoxide
8-Hour Daily Maximum through December 2, 2025
Standard: 8-hour daily maximums shall not exceed 9 ppm more than once per year.
Site	Highest 8-hour Maximums (ppm)
	2022		2023		2024		2025*
	1st	2nd	1st	2nd	1st	2nd	1st	2nd
Tulsa Central	1.0	0.8	1.0	1.0	1.1	0.9	0.7	0.7
OKC North	0.7	0.7	0.9	0.9	1.2	1.2	0.9	0.8
OKC Near Road	1.5	1.3	1.2	1.2	1.4	1.4	1.3	1.1
*All data is subject to change upon QA/QC -- data collection for 2025 is ongoing.