April 25, 2025

AQS Reference Table

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Downoad a csv version: pollutant_standards.csv

Parameter Code	Parameter	Pollutant Standard ID	Pollutant Standard Short Name	Pollutant Standard Description	NAAQS Basis	NAAQS Statistic	Primary Standard Level	Standard Units	Comparison Scale	Round or Truncate	Excludable
42101	Carbon monoxide	3	CO 1-hour 1971	Carbon Monoxide 1-hour standard from 1971.	Obseved hourly values	Annual Second Maximum	35.0	Parts per million	0	R
42101	Carbon monoxide	4	CO 8-hour 1971	Carbon Monoxide 8-hour running average from 1971.	8-Hour running average (end hour) of observed hourly values	Annual Second Non-Overlapping Maximum	9.0	Parts per million	0	R
14129	Lead (TSP) LC	2	Lead 3-Month 2009	Lead 3 month rolling average site level summary based on TSP lead at local conditions.	Observed Values	3-Month Rolling Average	0.15	Micrograms/cubic meter (LC)	2	R
12128	Lead (TSP) STP	1	Lead Quarterly 1978	Original lead standard based on calendar quarterly average.	Observed Values	Quarterly Mean	1.5	Micrograms/cubic meter (25 C)	1	R
85129	Lead PM10 LC FRM/FEM	14	Lead 3-Month PM10 Surrogate 2009	PM10 Surgate (instead of TSP) for the new lead 3 month rolling average site level summary.	Observed Values	3-Month Roling Average	0.15	Micrograms/cubic meter (LC)	2	R
42602	Nitrogen dioxide (NO2)	20	NO2 1-hour 2010	Nitrogen Dioxide 1-hour standard	Daily Maximum 1-hour average	Annual 98th Percentile	100.0	Parts per billion	0	R
42602	Nitrogen dioxide (NO2)	8	NO2 Annual 1971	Nitrogen Dioxide Annual Mean from 1971.	Observed values	Annual Mean	53.0	Parts per billion	0	R
44201	Ozone	9	Ozone 1-hour 1979	Ozone 1-hour Daily Maximum value based on data completeness betweeen 9 AM and 9 pm.	Daily maxima of observed hourly values (between 9:00 AM and 8:00 PM)	Annual Estimated Days > Standard	0.12	Parts per million	2	R
44201	Ozone	10	Ozone 8-Hour 1997	Ozone 8-hour running average stored in begin hour from 1997.	Daily maximum of 8 hour running average of observed hourly values	Annual 4th Maximum	0.08	Parts per million	2	R
44201	Ozone	11	Ozone 8-Hour 2008	Ozone 8-hour running average stored in begin hour from 2008.	Daily maximum of 8 hour running average of observed hourly values	Annual 4th Maximum	0.075	Parts per million	3	T
44201	Ozone	23	Ozone 8-hour 2015	Ozone 8-hour 2015 -- Daily 8-hour maximum between 7:00 AM and 11:00 PM	Daily maximum of 8-hour running average	Annual 4th Maximum	0.07	Parts per million	3	T
81102	PM10 Total 0-10um STP	12	PM10 24-hour 2006	PM10 24-hour standard. Violations include actual exceedences and expected exceedences where data is missing.	Daily Mean	Annual Estimated Days > Standard	150.0	Micrograms/cubic meter (25 C)	-1	R
88101	PM2.5 - Local Conditions	25	PM25 Annual 1997	PM25 Annual standard for 1997. Created for Region 9 / AQAD	Quarterly Means of Daily Means	Annual Weighted Mean	15.0	Micrograms/cubic meter (LC)	1	R	Y
88101	PM2.5 - Local Conditions	24	PM25 24-hour 1997	PM25 24-hour standard for 1997. Created for Region 9 / AQAD	Daily Mean	Annual 98th Percentile	65.0	Micrograms/cubic meter (LC)	0	R
88101	PM2.5 - Local Conditions	16	PM25 24-hour 2006	PM25 24-hour standard made more restrictive in 2006.	Daily Mean	Annual 98th Percentile	35.0	Micrograms/cubic meter (LC)	0	R
88101	PM2.5 - Local Conditions	18	PM25 Annual 2006	PM25 annual weighted mean was reaffirmed in 2006 with the same level as originally promulgated.	Quarterly Means of Daily Means	Annual Weighted Mean	15.0	Micrograms/cubic meter (LC)	1	R	Y
88101	PM2.5 - Local Conditions	21	PM25 24-hour 2012	PM25 24-hour standard was reaffirmed in 2013 with the same level as previously promulgated.	Daily Mean	Annual 98th Percentile	35.0	Micrograms/cubic meter (LC)	0	R
88101	PM2.5 - Local Conditions	22	PM25 Annual 2012	PM25 annual standard was lowered in 2013 to increase protection against health effects with long-term exposures.	Quarterly Means of Daily Means	Annual Weighted Mean	12.0	Micrograms/cubic meter (LC)	1	R	Y
88101	PM2.5 - Local Conditions	27	PM25 Annual 2024	PM25 annual standard was lowered in 2024 to increase protection against health effects with long-term exposures.	Quarterly Means of Daily Means	Annual Weighted Mean	9.0	Micrograms/cubic meter (LC)	1	R	Y
88101	PM2.5 - Local Conditions	26	PM25 24-hour 2024	PM25 24-hour standard was reaffirmed in 2024 with the same level as previously promulgated.	Daily Mean	Annual 98th Percentile	35.0	Micrograms/cubic meter (LC)	0	R
42401	Sulfur dioxide	7	SO2 Annual 1971	Sulfur Dioxide Annual Mean Standard from 1971.	Observed Values	Annual Mean	30.0	Parts per billion	0	R
42401	Sulfur dioxide	6	SO2 24-hour 1971	Sulfur Dioxide 24-hour standard from 1971.	Daily Average of observed values	Annual Second Maximum	140.0	Parts per billion	0	R
42401	Sulfur dioxide	5	SO2 3-hour 1971	Sulfur Dioxide 3-hour Block Average from 1971.	3-Hour block average of observed hourly values	Annual Second Maximum		Parts per billion	0	R
42401	Sulfur dioxide	19	SO2 1-hour 2010	Sulphur Dioxide 1-hour standard from 2010	Daily maximum 1-hour average	Annual 99th Percentile	75.0	Parts per billion	0	R
42401	Sulfur dioxide	28	SO2 Annual 2024	Secondary SO2 standard revised to be an annual standard.	Observed Values	Annual Mean		Parts per billion	0	R