Oklahoma Department of Environmental Quality
2026 NO2
8th Highest One Hour Daily Maximum through February 16, 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 36.0 41.0 39.3
OKC North 29.0 27.0 30.0 31.0 28.7 29.3
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. The software function we use to pull these values is nonoperational, this chart will be updated when possible.