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Eight-Hour Ozone High Value Days for 2014
as of July 23

The table below lists the daily maximum eight-hour ozone concentrations measured which meet or exceed 76 parts per billion in 2014 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.

YearSort ByReport Format
Highlight with AQI colors
2014 Sorted by Maximum Value
Heritage Middle School C622 13 62248_029_0622May 30 201411:00911 N
Mustang Bayou C619 12 61948_039_0619May 29 201412:00821 N
Calaveras Lake C59 13 5948_029_0059May 30 201411:00811
SETRPC 40 Sabine Pass C640/C1654 10 64048_245_0101May 2 201413:00801
UH West Liberty C699 12 69948_291_0699May 3 201411:00801 N
Conroe Relocated C78/A321 12 7848_339_0078May 5 201410:00801
SETRPC Mauriceville 42 C642/C311/C665 10 64248_361_1100May 3 201410:00791 N
Ft. Worth Northwest C13/AH302 4 1348_439_1002July 22 201411:00792
Denton Airport South C56/A163/X157 4 5648_121_0034July 16 201410:00781
Pilot Point C1032 4 103248_121_1032June 11 201411:00781
Wallisville Road C617 12 61748_201_0617June 11 201408:00781 N
UH West Liberty C699 12 69948_291_0699May 4 201410:00781 N
Beaumont-Downtown C2/A112/C2002 10 248_245_0009May 3 201410:00772
UH WG Jones Forest C698 12 69848_339_0698May 5 201410:00771 N
CPS Pecan Valley C678 13 67848_029_0055May 30 201411:00761 N
Wallisville Road C617 12 61748_201_0617May 2 201411:00761 N
UH West Liberty C699 12 69948_291_0699May 5 201408:00761 N
UH WG Jones Forest C698 12 69848_339_0698July 16 201412:00761 N
Holly Road C660 14 66048_355_0660May 29 201411:00761 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

Air Quality Index

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 - 0.059
51 - 100 Not Defined 0.06 - 0.075
101 - 150 0.125 - 0.164 0.076 - 0.095
151 - 200 0.165 - 0.204 0.096 - 0.115
201 - 300 0.205 - 0.404 0.116 - 0.374
301 - 400 0.405 - 0.504 Not Defined
401 - 500 0.505 - 0.604 Not Defined
500+ Not Defined Not Defined

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 beginning 1/1/2013, 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.