Oklahoma Department of Environmental Quality
2026 Carbon Monoxide
8-Hour Daily Maximum through July 27, 2026
Standard: 8-hour daily maximums shall not exceed 9 ppm more than once per year.
Site	Highest 8-hour Maximums (ppm)
	2023		2024		2025		2026*
	1st	2nd	1st	2nd	1st	2nd	1st	2nd
Tulsa Central	1.0	1.0	1.1	0.9	0.7	0.7	0.8	0.5
OKC North	0.9	0.9	1.2	1.2	0.9	0.8	1.2	1.2
Tulsa Near Road	-	-	-	-	-	-	0.4	0.4
OKC Near Road	1.2	1.2	1.4	1.4	1.3	1.1	1.2	1.2