Oklahoma Department of Environmental Quality
2026 SO2
4th Highest 1-Hour Average through January 25, 2026
Standard: The 99th percentile of 1-hour daily max concentrations averaged across 3 years must be below 75 ppb.
Site 99th Percentile (ppb) 3-Yr Avg.
  2023 2024 2025 2026* 23-25 24-26*
Ponca City 5.0 7.0 9.0 0.0 7.0 5.3
OKC North 1.0 1.0 1.0 0.0 1.0 0.7
Tulsa Newblock 8.0 4.0 4.0 0.0 5.3 2.7
Tulsa TCWD 5.0 1.0 2.0 0.0 2.7 1.0
Tulsa Central** 3.1 2.8 1.6 0.0 2.5 1.5
Oxbow/Kremlin 37.0 47.0 28.0 1.0 37.3 25.3
*4th highs are considered 99th percentile until end of year data completeness is calculated
**Tulsa Central is temporarily closed for building repairs.