Air Quality Index - Texas Commission on Environmental Quality

Air Quality Index

How clean is the air in your metropolitan area? 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.

Interpreting the AQI

Reporting for October 5, 2009 as of 4:17 pm CDT
Metropolitan Area or Non-Metropolitan County		Air Quality		Critical Pollutant	Air Quality Index Rating
					Ozone				Carbon Monoxide		Sulfur Dioxide		PM-10 (Std Cond)		PM-2.5 (Lcl Acpt)
					1-Hour		8-Hour		8-Hour		24-Hour †		24-Hour †		24-Hour †
					AQI	ppb	AQI	ppb	AQI	ppm	AQI	ppb	AQI	ug/m3	AQI	ug/m3
Amarillo -- Region 1
	Amarillo		Good	PM-2.5											14	4.2
Lubbock -- Region 2
	Lubbock		Good	PM-2.5											13	4.1
Abilene -- Region 3
	Wichita Falls		Good	PM-2.5											8	2.5
DFW -- Region 4
	Dallas ¹		Good	PM-2.5	*	30	22	26	3	0.2	0	0			25	7.6
	Fort Worth-Arlington		Good	PM-2.5	*	26	18	21	3	0.3					23	7.1
	Navarro County		Good	Ozone	*	25	16	19			0	0			15	4.6
Tyler -- Region 5
	Longview-Marshall		Good	Ozone	*	28	19	23			0	0			11	3.4
	Tyler		Good	Ozone	*	29	18	21
El Paso -- Region 6
	Brewster County	††			*	22		‡								§
	El Paso ¹		Good	Ozone	*	29	21	25	6	0.5	0	0	16	17.8	9	2.7
	Jeff Davis County		Good	PM-2.5											6	1.7
	Juarez ¹		Good	Ozone	*	27	15	18	9	0.8
Midland -- Region 7
	Odessa-Midland		Good	PM-2.5											29	8.9
Waco -- Region 9
	Killeen-Temple		Good	Ozone	*	22	14	16
	Waco		Good	PM-2.5	*	23	17	20	1	0.1	1	0			20	6.2
Beaumont -- Region 10
	Beaumont-Port Arthur		Good	PM-2.5	*	43	16	19	0	0.0	2	1			26	8.1
Austin -- Region 11
	Austin-San Marcos ¹		Good	PM-2.5	*	27	14	16		§					22	6.7
	Fayette County		Good	PM-2.5	*	19	7	8			0	0			23	7.2
Houston -- Region 12
	Brazoria		Good	Ozone	*	29	14	17
	Galveston-Texas City		Good	PM-2.5	*	25	15	18			2	2			39	12.1
	Houston ¹		Good	PM-2.5	*	68	18	21	5	0.4	10	7			50	15.5
San Antonio -- Region 13
	San Antonio ¹		Good	PM-2.5	*	34	11	13	3	0.3	0	0	17	17.9	42	13.0
Corpus Christi -- Region 14
	Corpus Christi		Good	PM-2.5	*	33	25	29			0	0			44	13.6
	Victoria		Good	Ozone	*	23	15	18
Harlingen -- Region 15
	Brownsville-Harlingen-San Benito		Good	PM-2.5	*	25	16	19	1	0.1			23	24.6	46	14.1
	McAllen-Edinburg-Mission		Good	PM-2.5	*	28	19	23					20	21.9	44	13.6
Laredo -- Region 16
	Laredo		Moderate	PM-2.5	*	28	18	21	8	0.7			24	25.7	54	17.0
	Maverick County		Moderate	PM-2.5											59	19.7
PM-10 is measured at standard pressure and temperature conditions.
PM-2.5 Acceptable is measured at local pressure and temperature conditions.
† This is an average since midnight for the current day and does not represent an entire day's worth of data.
†† No AQI has been calculated for this metropolitan area. This can happen early in the morning before enough valid ozone or carbon monoxide hourly samples have been collected to create an eight-hour average and should clear up once enough samples are collected. If there are no measurements for any parameter, this indicates a data collection problem. Once this problem is resolved, the data will be filled in and a AQI will be calculated (if possible).
¹ Not all monitors are reporting for this metropolitan area.
§ No data of this type was collected on October 5, 2009 for this metropolitan area, or there were not enough valid hourly samples collected on this date to meet data completeness requirements of a minimum of 18 valid hourly samples in a day, or there have not been enough valid carbon monoxide hourly samples collected to create an eight-hour average.
‡ There are not enough valid ozone hourly samples accumulated on October 5, 2009 to create eight-hour ozone averages.
* There is no AQI associated with hourly ozone averages less than 0.125 ppm (125 ppb).

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.

Interpreting the AQI

Each NAAQS pollutant has a separate AQI scale, with a 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

The AQI scale is divided into the following categories:

	Air Quality

	Good		Moderate		Unhealthy (for sensitive groups)		Unhealthy		Very Unhealthy		Hazardous
0		51		101		151		201		301+
	The AQI Air Quality Scale

The AQI for ozone is based on the either the peak eight-hour running average since midnight OR the peak one-hour measurement since midnight. The AQI's for sulfur dioxide, PM-10, and PM-2.5 are based on a 24-hour average sampled from midnight to midnight, and the AQI for carbon monoxide is based on the peak eight-hour running average since midnight. On most days the critical pollutant is ozone. Ozone one-hour average concentrations of 125 ppb or higher exceed the old NAAQS ( AQI rating of 106 or higher). The new NAAQS for ozone is based on eight-hour averages and applies in all areas that are classified as attainment for the old one-hour NAAQS. An eight-hour average of 75 ppb exceeds the new NAAQS for ozone. All areas currently classified as nonattainment for the old one-hour standard will still be required to achieve attainment of the one-hour standard (Houston-Galveston-Brazoria, Dallas-Fort Worth, El Paso, and Beaumont-Port Arthur).