Eight-Hour Ozone High Value Days for 2020
as of May 29
The table below lists the daily maximum eight-hour ozone concentrations measured which meet or exceed 71 parts per billion in 2020 in each community where the TCEQ measures ozone. This information is updated hourly. Concentrations are color-highlighted based on the EPA-defined Air Quality Index colors. (See Interpreting the AQI.) Times shown are in 24-hour format and are Local Standard Time. Our convention is that the time reflects the beginning of the eight-hour average. All ozone measurements are in parts per billion.Use the selection boxes below to customize this report. You may select a different year, a different sorting order, or a different report format. Click on the Generate Report button once you have made your selections.
| 2020 Sorted by Maximum Value | |||||||
|---|---|---|---|---|---|---|---|
| Location | Region | CAMS | AQS | Date | Time | Value | POC |
| Texas City 34th St. C620 | 12 | 620 | 48_167_0056 | May 18 2020 | 10:00 | 88 | 1 N |
| Houston East C1/G316 | 12 | 1 | 48_201_1034 | May 18 2020 | 10:00 | 86 | 2 |
| Grapevine Fairway C70/A301/X182 | 4 | 70 | 48_439_3009 | May 19 2020 | 10:00 | 86 | 1 |
| Baytown Wetlands Center C552 | 12 | 552 | 48_201_0552 | May 18 2020 | 10:00 | 85 | 1 N |
| Ft. Worth Northwest C13/AH302 | 4 | 13 | 48_439_1002 | May 19 2020 | 11:00 | 83 | 2 |
| Camp Bullis C58 | 13 | 58 | 48_029_0052 | April 30 2020 | 11:00 | 81 | 1 |
| Channelview C15/AH115 | 12 | 15 | 48_201_0026 | May 18 2020 | 10:00 | 81 | 3 |
| Wallisville Road C617 | 12 | 617 | 48_201_0617 | May 18 2020 | 11:00 | 81 | 1 N |
| Baytown Garth C1017 | 12 | 1017 | 48_201_1017 | May 18 2020 | 11:00 | 81 | 1 |
| Hou.DeerPrk2 C35/235/1001/AFH139FP239 | 12 | 35 | 48_201_1039 | May 18 2020 | 10:00 | 81 | 1 |
| La Porte Sylvan Beach C556 | 12 | 556 | 48_201_0556 | May 18 2020 | 10:00 | 79 | 1 N |
| HRM-3 Haden Road C603/A114 | 12 | 603 | 48_201_0803 | May 18 2020 | 10:00 | 79 | 1 N |
| Pilot Point C1032 | 4 | 1032 | 48_121_1032 | May 18 2020 | 12:00 | 78 | 1 |
| UH Moody Tower C695 | 12 | 695 | 48_201_0695 | May 18 2020 | 10:00 | 77 | 1 N |
| Galveston 99th St. C1034/A320/X183 | 12 | 1034 | 48_167_1034 | May 18 2020 | 10:00 | 76 | 1 |
| Lynchburg Ferry C1015/A165 | 12 | 1015 | 48_201_1015 | May 18 2020 | 10:00 | 76 | 1 |
| Dallas Hinton St. C401/C60/AH161 | 4 | 401 | 48_113_0069 | May 19 2020 | 11:00 | 75 | 3 |
| Denton Airport South C56/A163/X157 | 4 | 56 | 48_121_0034 | May 18 2020 | 11:00 | 75 | 1 |
| El Paso UTEP C12/A125/X151/G125 | 6 | 12 | 48_141_0037 | May 9 2020 | 11:00 | 75 | 2 |
| Texas City 34th St. C620 | 12 | 620 | 48_167_0056 | April 23 2020 | 10:00 | 75 | 1 N |
| Seabrook Friendship Park C45 | 12 | 45 | 48_201_1050 | May 18 2020 | 10:00 | 75 | 1 |
| UH Launch Trailer C1611 | 12 | 1611 | 48_201_1611 | May 18 2020 | 10:00 | 75 | 1 N |
| Conroe Relocated C78/A321 | 12 | 78 | 48_339_0078 | May 1 2020 | 10:00 | 75 | 1 |
| El Paso UTEP C12/A125/X151/G125 | 6 | 12 | 48_141_0037 | May 6 2020 | 10:00 | 74 | 2 |
| Houston Aldine C8/AF108/X150 | 12 | 8 | 48_201_0024 | May 18 2020 | 11:00 | 74 | 2 |
| Northwest Harris Co. C26/A110/X154 | 12 | 26 | 48_201_0029 | May 11 2020 | 11:00 | 74 | 2 |
| Eagle Mountain Lake C75 | 4 | 75 | 48_439_0075 | May 19 2020 | 10:00 | 74 | 1 |
| Keller C17 | 4 | 17 | 48_439_2003 | May 19 2020 | 11:00 | 74 | 2 |
| Frisco C31/C680 | 4 | 31 | 48_085_0005 | May 18 2020 | 11:00 | 73 | 1 |
| Socorro Hueco C49/F312 | 6 | 49 | 48_141_0057 | May 9 2020 | 11:00 | 73 | 1 |
| Camp Bullis C58 | 13 | 58 | 48_029_0052 | April 20 2020 | 11:00 | 72 | 1 |
| Dallas North No.2 C63/C679 | 4 | 63 | 48_113_0075 | May 19 2020 | 10:00 | 72 | 1 |
| Chamizal C41/AH126 | 6 | 41 | 48_141_0044 | May 9 2020 | 11:00 | 72 | 1 |
| Houston Bayland Park C53/A146 | 12 | 53 | 48_201_0055 | April 20 2020 | 12:00 | 72 | 1 |
| Dripping Springs School C614 | 11 | 614 | 48_209_0614 | May 18 2020 | 11:00 | 72 | 1 N |
| Conroe Relocated C78/A321 | 12 | 78 | 48_339_0078 | April 24 2020 | 11:00 | 72 | 1 |
| Dallas North No.2 C63/C679 | 4 | 63 | 48_113_0075 | May 18 2020 | 12:00 | 71 | 1 |
| Houston Westhollow C410 | 12 | 410 | 48_201_0066 | April 20 2020 | 12:00 | 71 | 1 |
| Huffman Wolf Road C563 | 12 | 563 | 48_201_0563 | May 18 2020 | 12:00 | 71 | 1 N |
| Clinton C403/C304/AH113 | 12 | 403 | 48_201_1035 | May 18 2020 | 10:00 | 71 | 3 |
| UH WG Jones Forest C698 | 12 | 698 | 48_339_0698 | May 1 2020 | 10:00 | 71 | 1 N |
| POC (Parameter Occurrence Code): a code used to correctly separate data from multiple instruments at one site. | |||||||
| N - Data from this instrument does not meet EPA quality assurance criteria and cannot be used for regulatory purposes. | |||||||
Interpreting the AQI
Each NAAQS pollutant has a separate AQI scale, with an AQI rating of 100 corresponding to the concentration of the Federal Standard for that pollutant. Additional information about the AQI and how it can be used is available from the EPA's AirNow web site.
Place your mouse pointer over the scale displayed above to view information about the Air Quality Index, and each of the rating levels.
The actual index calculation is different for each parameter measured and is specified by the EPA. The following table shows the various breakpoints used in calculating the AQI.
| AQI Breakpoint Definitions | ||
|---|---|---|
| AQI Range | 1hr Ozone in ppm |
8hr Ozone in ppm |
| 0 - 50 | Not Defined | 0 - 0.054 |
| 51 - 100 | Not Defined | 0.055 - 0.070 |
| 101 - 150 | 0.125 - 0.164 | 0.071 - 0.085 |
| 151 - 200 | 0.165 - 0.204 | 0.086 - 0.105 |
| 201 - 300 | 0.205 - 0.404 | 0.106 - 0.200 |
| 301 - 400 | 0.405 - 0.504 | Not Defined |
| 401 - 500 | Not Defined | Not Defined |
| 500+ | Not Defined | Not Defined |
- The AQI for ozone is based on either the peak eight-hour running average since midnight OR the peak one-hour measurement since midnight.
PLEASE NOTE: This data has not been verified by the TCEQ and may change. This is the most current data, but it is not official until it has been certified by our technical staff. Data is collected from TCEQ ambient monitoring sites and may include data collected by other outside agencies. This data is updated hourly. All times shown are in local standard time unless otherwise indicated.
Following EPA reporting guidelines, negative values may be displayed in our hourly criteria air quality data, down to the negative of the EPA listed Method Detection Limit (MDL) for the particular instrument that made the measurements. The reported concentrations can be negative due to zero drift in the electronic instrument output, data logger channel, or calibration adjustments to the data. Prior to 1/1/2013, slightly negative values were automatically set to zero.