Oklahoma Department of Environmental Quality
2026 NO2
8th Highest One Hour Daily Maximum through January 25, 2026
Standard: 3-year average of the 98th percentile of 1-hour data shall not exceed 100 ppb
Site 98th Percentile (ppb) 3-yr Avg.
  2023 2024 2025 2026* 23-25 24-26*
OKC Near Road 41.0 40.0 42.0 33.0 41.0 38.3
OKC North 29.0 27.0 30.0 29.0 28.7 28.7
Tulsa Central** 32.7 29.5 30.4 0.0 30.9 20.0
8th Highs are considered 98th percentile until end of year data completeness is calculated. 
*All data is subject to change upon QA/QC -- data collection for 2026 is ongoing.