San Antonio Metropolitan Area - Texas Commission on Environmental Quality

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San Antonio Metropolitan Area

Air Quality Index

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.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

Interpreting the AQI

Reporting for November 7, 2009 as of 4:18 pm CST
Monitoring Sites in the San Antonio Metro Area		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
Bexar County			Good	O3	*	52	37	44	7	0.7	1	1	12	13.4	33	10.2
	CPS Pecan Valley C678		Good	PM2.5(Lcl)accpt	*	46	29	34	7	0.7	1	1			33	10.0
	Calaveras Lake C59		Good	O3	*	46	31	37							30	9.2
	Camp Bullis C58		Good	O3	*	50	37	44
	Elm Creek Elementary C501 ¹	††				§		§
	Fair Oaks Ranch C502 ¹	††				§		§
	Heritage Middle School C622		Good	PM2.5(Lcl)accpt	*	46	30	35	3	0.3	0	0			33	10.2
	Old Highway 90 C677/A319		Good	PM2.5(Lcl)accpt											32	9.9
	Palo Alto C676		Good	PM2.5(Lcl)accpt											31	9.6
	San Antonio Downtown C27		Good	CO					3	0.3
	San Antonio Northwest C23		Good	O3	*	52	37	44
	Selma C301		Good	PM2.5(Lcl)accpt									12	13.4	29	9.0


Comal County		††						‡
	Bulverde Elementary C503 ¹	††				§		§
	City of Garden Ridge C505 ¹	††				§		§


Guadalupe County		††						‡
	New Braunfels Airport C504 ¹	††				§		§
	Seguin Outdoor Learning Center C506 ¹	††				§		§
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 site. 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 This monitoring site is not reporting.
§ No data of this type was collected on November 7, 2009 for this site, 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 November 7, 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 information is available for each specific site by clicking on the site 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 concentrations for each pollutant, the corresponding Air Quality Index (AQI) category, and the AQI ratings for each of the NAAQS pollutants that are measured real-time. 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 monitoring site within the San Antonio metropolitan area where pollutant levels are monitored by the TCEQ. Critical pollutant concentrations for ozone and sulfur dioxide are shown in parts per billion (ppb), carbon monoxide measurements are shown in parts per million (ppm), and particulate matter (PM-10 and PM-2.5) concentrations are shown in micrograms per cubic meter (ug/m3).

The AQI for ozone is based on 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).

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.