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Air Quality Index Report

The U. S. Environmental Protection Agency (EPA) has provided a scale called the Air Quality Index (AQI) for rating air quality. This scale is based on the National Ambient Air Quality Standards (NAAQS) and is described in the Code of Federal Regulations, Part 58, Appendix G. This report is based on the AQI standards. More information on the AQI can be found on the EPA's AirNow web site.

Reporting for April 16, 2014 as of 7:12 pm CDT                  
Metropolitan Area
or
Non-Metropolitan County
Air Quality RatingCritical
Pollutant
Air Quality Index
OzoneCarbon MonoxideSulfur DioxideNitrogen DioxidePM-10
(Std Cond)
PM-2.5
(Lcl Acpt)
1-Hour8-Hour8-Hour1-Hour1-Hour24-Hour (2)24-Hour (2)
AQIppbAQIppbAQIppmAQIppbAQIppbAQIµg/m³ (25° C)AQIµg/m³ LC
Amarillo -- Region 1
Amarillo Good PM-2.5             6 4         28 6.7
Lubbock -- Region 2
Lubbock Good PM-2.5                         38 9.1
Dallas-Fort Worth -- Region 4
Dallas Good Ozone * 64 50 59 2 0.2 4 2 18 19     31 7.5
Fort Worth-Arlington Moderate Ozone * 69 61 63 3 0.3     21 23     31 7.4
Navarro County Good Ozone * 52 42 50     4 3 9 10     30 7.2
Tyler-Longview-Marshall -- Region 5
Longview-Marshall Good Ozone * 52 42 49     4 2 14 15     24 5.7
Tyler Good Ozone * 50 41 48         4 4        
El Paso-Juarez -- Region 6
Brewster County Good Ozone * 54 43 51                 26 6.2
El Paso Good Ozone * 56 44 52 6 0.5 12 8 44 47   §  §
Juarez (1) Good Carbon Monoxide   §§  §8 0.7                
Odessa-Midland -- Region 7
Odessa-Midland Good PM-2.5                         33 8.0
Waco -- Region 9
Killeen-Temple Moderate Ozone * 62 51 60                    
Waco (1) Good Ozone * 61 46 54 1 0.1 1 1 4 4       §
Beaumont-Port Arthur -- Region 10
Beaumont-Port Arthur Good Ozone * 54 43 51 1 0.1 5 3 28 30     32 7.6
Austin -- Region 11
Austin-San Marcos Good Ozone * 60 48 57 2 0.2 2 1 24 26     30 7.1
Fayette County Good Ozone * 57 46 54                 24 5.8
Houston-Galveston-Brazoria -- Region 12
Brazoria Good Ozone * 52 43 51         20 22        
Galveston-Texas City Good Ozone * 55 45 53 2 0.2 2 2 4 4       §
Houston (1) Good PM-2.5 * 63 47 56 3 0.3 5 4 42 45     50 11.9
San Antonio -- Region 13
San Antonio (1) Moderate Ozone * 65 61 63 3 0.3 8 6 28 30     32 7.6
Corpus Christi-Victoria -- Region 14
Corpus Christi (1) Good Ozone * 62 49 58     2 2         30 7.2
Victoria Good Ozone * 53 43 51         16 16        
Lower Rio Grande Valley -- Region 15
Brownsville-Harlingen-San Benito Good Ozone * 54 44 52 ## -0.4             28 6.7
McAllen-Edinburg-Mission Good Ozone * 51 41 48                 37 8.8
Laredo -- Region 16
Laredo Good Ozone * 55 44 52 5 0.4               §
Maverick County Good PM-2.5                         25 6.0
The highest AQI value and associated average (1-hour, 8-hour, or 24-hour) that is responsible for the AQI rating are highlighted bold in the table.
PM-10 is measured at standard pressure and temperature conditions.
PM-2.5 is measured at local pressure and temperature conditions.
(1) - Not all monitors are reporting for this metropolitan area.
(2) - This is an average since midnight for the current day and does not represent an entire day of data.
The reported overall AQI category chould change and will not be complete until all the data for the calendar day is polled and processed and could be further subject to later change by the data validation process.
§ - Less than 75% of the samples in the averaging period have been collected.
§§ - There have been no hourly averages of this parameter collected for April 16, 2014 in this metropolitan area.
* - There is no AQI associated with hourly ozone averages less than 0.125 ppm (125 ppb).
## - No AQI is defined for negative values.

PLEASE NOTE:  Data in this table is collected from TCEQ air monitoring sites, local agencies, and private monitoring networks. Site specific information is available for each metropolitan area by clicking on the metropolitan area name. This data has not been verified by the TCEQ or the responsible entity and may change. While this is the most current data, it is not official until it has been certified by the appropriate technical staff. This table is updated hourly. Click here for information about all the monitoring sites.

The table above lists the current peak concentration for the critical pollutant, the corresponding Air Quality Index (AQI) category, and the AQI ratings for each of the NAAQS pollutants that are measured real-time. The critical pollutant is the pollutant with the highest AQI rating measured in the area. The table is updated each hour and covers the period from midnight through the indicated ending time for today's data or from midnight to midnight on other days. Listings are provided for each metropolitan area where pollutant levels are monitored by TCEQ.

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
8hr Carbon Monoxide
in ppm
1hr Sulfur Dioxide
in ppm
24hr Sulfur Dioxide
in ppm
1hr Nitrogen Dioxide
in ppm
24hr PM-10
in µg/m³ (25° C)
24hr PM-2.5
in µg/m³ LC
0 - 50 Not Defined 0 - 0.059 0 - 4.4 0 - 0.035 Not Defined 0 - 0.053 0 - 54 0 - 12.0
51 - 100 Not Defined 0.06 - 0.075 4.5 - 9.4 0.036 - 0.075 Not Defined 0.054 - 0.1 55 - 154 12.1 - 35.4
101 - 150 0.125 - 0.164 0.076 - 0.095 9.5 - 12.4 0.076 - 0.185 Not Defined 0.101 - 0.36 155 - 254 35.5 - 55.4
151 - 200 0.165 - 0.204 0.096 - 0.115 12.5 - 15.4 0.186 - 0.304 Not Defined 0.361 - 0.64 255 - 354 55.5 - 150.4
201 - 300 0.205 - 0.404 0.116 - 0.374 15.5 - 30.4 Not Defined 0.305 - 0.604 0.65 - 1.24 355 - 424 150.5 - 250.4
301 - 400 0.405 - 0.504 Not Defined 30.5 - 40.4 Not Defined 0.605 - 0.804 1.25 - 1.64 425 - 504 250.5 - 350.4
401 - 500 0.505 - 0.604 Not Defined 40.5 - 50.4 Not Defined 0.805 - 1.004 1.65 - 2.04 505 - 604 350.5 - 500.4
500+ Not Defined Not Defined Not Defined Not Defined Not Defined Not Defined 605 - 4999 500.5 - 999.9

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.