Air Monitoring Station Search Criteria Help - CAPs
The Air Monitor Station Search allows users to search for U.S. air monitoring stations monitoring for either Hazardous Air Pollutants (HAPs) or Criteria Air Pollutants (CAPs). This webpage focuses on CAPs search criteria.
Search criteria are organized through the hyperlinks below to allow you to quickly find the search term of interest.
By Category
Alphabetically
- Air Concentration Trend
- AQS Site Code(s)
- Based On
- Choose a Timeframe
- Choose Search Type
- City
- Classification
- Compare To
- Comparison to NAAQS
- Count of Indexes
- County
- EJ Indexes At or Above 80th Percentile
- EPA Region
- FRS Tribal Land Code
- ICIS Tribal Land Flag
- Index Type
- Indian Country/Tribal Land, Find Stations that Match
- Located on Tribal Land
- Location Type
- Monitor located in Nonattainment Area
- NAAQ Standard
- Nonattainment Area
- Number of NAAQS Exceedances
- On or Near Spatial Tribal Boundary
- Percent Low Income
- Percent People of Color
- Pollutant
- Pollutant Name
- Pollutant Standard
- Population Density Greater than (per sq. mile)
- Regional Planning Organization (RPO)
- State
- Tribes
- Zip Code
Search Type
Specify a search type and/or choose to go directly to a nationwide map of ambient monitoring stations.
Choose to either search for monitors measuring criteria air pollutants or hazardous air pollutants. The search criteria in latter sections of the search form will change depending on this selection. To learn for about searching for HAP monitors, see Air Monitoring Station Search Criteria Help - HAPs.
Geographic Location
Search for air monitoring stations based on their location information in the Air Quality System (AQS) dataset.
Enter up to a five-digit ZIP code. Entering a partial ZIP code results with any ZIP beginning with the entered value. You may not combine a ZIP Code search with an EPA Region search. We do not recommend combining a search by ZIP code with city and state search criteria.
Use to search for air monitoring stations in a particular EPA Region. Choose a region from the dropdown menu. You may not combine EPA Region search with a city/state, state, or RPO search.
Search for air monitoring stations within one of the five EPA funded RPOs to address air quality issues:
- Western Regional Air Partnership (WRAP)
- Central Regional Air Planning Association (CENRAP)
- Midwest Regional Planning Organization (Midwest RPO)
- Mid-Atlantic/Northeast Visibility Union (MAN-VU), and
- Visibility Improvement State and Tribal Association of the Southeast (VISTAS).
You may not combine RPO search with a city/state, state, or EPA Region search.
Choose a state from the dropdown menu. You may not combine a state search with an EPA region or RPO search.
After you choose a state, the County dropdown menu is populated with state-specific county options. The list of counties is not populated when multiple states are selected. You may not combine a county search with an EPA Region or RPO search.
To search for air monitoring stations in a particular city, you must first specify a state, using the State dropdown menu. Be sure to try all possible variations and alternate spellings of a city name (e.g., try both Saint Louis and St. Louis).
Search for stations that are located on or near tribal land. Search is based on EPA comparison of the station locations in EPA's Air Quality System to the U.S. Census Bureau 2016 tribal boundary layer data for tribes in the lower 48 states and Bureau of Land Management Alaska State Offie data for tribes in Alaska. When "Within X miles" is selected, your search results will be limited to stations of tribal land and within the selected radius. "No Restrictions" is selected by default and does not restrict search results. You can focus your search on a specific tribal land by using the "Tribes" criteria.
Data Quality Caveat: EPA makes no claims regarding the accuracy or precision of data concerning Indian country locations or tribal boundaries on the ECHO website. EPA has simply attempted to collect certain readily available information relating to Indian country locations. Questions concerning data should be referred to the originating program or Agency which can be identified in the Envirofacts tribal query metadata files Lower 48 Tribal Areas, Alaska Reservation, Alaska Native Villages, or Alaska Native Allotments. The Indian country and tribal boundary locations are suitable only for general spatial reference and do not necessarily reflect EPA's position on any Indian country locations or tribal boundaries or the land status of any specific location. The inclusion of Indian country information on the ECHO website does not represent any final EPA action addressing Indian country locations or boundaries. This information cannot be relied upon to create any rights, substantive or procedural, enforceable by any party in litigation with the United States or third parties. EPA reserves the right to change information on ECHO at any time without public notice.
EPA uses the U.S. Census Bureau 2016 tribal boundary layer data when developing environmental data query responses for tribes in the lower 48 United States and the Bureau of Land Management Alaska State Office when developing environmental data query responses for tribes in Alaska. EPA seeks to use the best available national federal data and may refine the tribal boundary layer in the future as more accurate national federal data becomes available.
Search for air monitors based on a location's population density and land use.
The AQS Site Code is a 9-digit unique identifier for the air monitoring station, created based on the combination of the State code + County code + Site Code. For example: 06 (state code) + 073 (county code) + 1201 (site code) = 060731201.
Site codes are unique for stations within a county. If only a site code is provided, ECATT will display all air monitoring stations with that site code. Similarly, ECATT will display all air monitoring stations within the state or county if only a state or county code is given respectively.
You can search for multiple IDs by using a comma-separated list.
Nonattainment AreaSearch for stations that are in a nonattainment or maintenance area for which EPA has developed GIS shapefiles. A nonattainment area is an area that does not meet one or more of the National Ambient Air Quality Standards (NAAQS) for six commonly found air pollutants ("criteria pollutants") designated in the Clean Air Act: particle pollution (often referred to as particulate matter), ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides, and lead.
Nonattainment areas are given a classification based on the severity of the violation and the type of air quality standard they exceed.
Select "No" to exclude monitors in nonattainment areas. Selecting "No" will deactivate the "Pollution", "Severity", and "Monitored pollutants correspond to nonattainment" options. Selecting "In Nonattainment Area" or "In Nonattainment or Maintenance Area" will allow you to specify those choices.
- Any Pollutant
- Carbon Monoxide
- Lead
- Nitrogen Oxides
- Ozone
- Sulfur Dioxide
- PM 2.5
- PM 10
Classifications available to search on are dependent on the pollutant selection. The complete list of classifications is below:
- Any Nonattainment
- Extreme
- Former Subpart 1
- Moderate
- Marginal
- Serious
- Severe-15
- Severe-17
- Submarginal
- Transitional (Section 185A)
Identify stations located within high or low population density areas according to the 2010 U.S. Census data. Enter a numeric value for total number of persons per land area (square miles).
Community
Environmental Justice
EJ Indexes At or Above 80th Percentile
Identify stations located in Census block groups at or above the 80th national percentile of one or more of the environmental justice (EJ) indexes of EJScreen, EPA's screening tool for EJ concerns. Select the number of indexes at or above the 80th national percentile using the slider. EPA uses EJScreen as a screening tool to identify geographic areas that may warrant further consideration or analysis. Note that use of this filter does not designate an area as an “EJ community” or “EJ facility.” EJScreen provides screening level indicators, not a determination of the existence or absence of EJ concerns. For more information, see the EJScreen home page.
Choose "US" or "State" to search for percentile values for EJ indexes nationwide or relative to Census block groups within the same state. The default is US.
Choose "Census Block Group" to search for percentile values based on the census block group the station is located in. Select "1-mile Maximum" to search based on the maximum percentile value for any census block group within a 1-mile radius of the station. The default is census block group.
Choose one of two methodologies for calculating EJScreen indexes. The indexes are a combination of environmental and socioeconomic information. The Environmental Justice Index uses a two-factor demographic index that averages Percent Low Income and Percent People of Color Populations. The Supplemental Index uses a five-factor demographic index that averages Percent Low Income, Percent Unemployed, Percent Limited English Speaking, Percent Less than High School Education, and Low Life Expectancy. The default is Supplemental Index.
Select the number of indexes at or above the 80th percentile of the environmental justice (EJ) indexes of EJScreen.
Demographics
Percent People of Color (3-mile radius)
Choose a percentage threshold to search for stations based on the racial composition of the surrounding three-mile radius. The field is calculated by subtracting the number of persons who are white (and not of Hispanic origin) from the total persons. This number is then divided by the total persons and multiplied by one hundred to determine the percentage.
Choose a percentage threshold to search for stations based on the percent of the population of the surrounding three-mile radius that have an income less than two times the poverty level, based on the 2015-2019 ACS 5-Year Summary.
Indian Country/Tribal Land
When "Yes" is selected, your search results will be limited to stations or permits flagged as being located in Indian country, based on information entered in EPA's Integrated Compliance Information System (ICIS). The accuracy and completeness of this information varies by system, and may differ from the FRS Tribal Land Code. "Indian country" is defined by statute at 18 U.S.C. 1151 to include all lands within Indian reservations, dependent Indian communities, and allotted lands. When "No" is selected, your search results will exclude any stations or permits that are located in Indian country. "Any" will not restrict search results.
When "Yes" is selected, your search results will be limited to stations or permits flagged as being located in Indian country, based on information that has been entered in EPA's Facility Registry Service. The accuracy and completeness of this information varies by data system. "Indian country" is defined by statute at 18 U.S.C. 1151 to include all lands within Indian reservations, dependent Indian communities, and allotted lands. When "No" is selected, your search results will exclude any stations or permits that are located in Indian country. "Any" will not restrict search results.
Search for stations that are located on or near tribal land. Search is based on EPA comparison of the station locations in its Facility Registry Service to the U.S. Census Bureau 2016 tribal boundary layer data for tribes in the lower 48 states and Bureau of Land Management Alaska State Office data for tribes in Alaska. When "Within X miles" is selected, your search results will be limited to stations or permits on tribal land and within the selected radius. "No Restrictions" is selected by default and does not restrict search results. You can focus your search on a specific tribal land using the "Tribes" criteria. Please note that stations must have locational data (latitude/longitude) in EPA's Facility Registry Service to be included in this search. Data Quality Caveat
Search for stations located on or near a tribe, based on spatial/locational association. The information is based on EPA comparison of station coordinates (in Facility Registry Service) to the U.S. Census Bureau 2016 tribal boundary layer data for tribes in the lower 48 states, and Bureau of Land Management Alaska State Office data for tribes in Alaska. Please note that stations must have locational data (latitude/longitude) in EPA's Facility Registry Service to be included in this search. Data Quality Caveat
Selection must be made in conjunction with the "On or Near Spatial Tribal Boundary" criteria. "No Restrictions" is selected by default and does not restrict search results. Enter at least one character. Select a tribe from the dropdown list to add it to the search criteria selected panel and clear the input field for a new value.
When "All Tribal Options" is selected, your search results will return stations that matches on all selected Indian Country/Tribal Land search criteria. When "Any Tribal Option" is selected, your search results will return stations that matches on any of the Indian Country Land search criteria selected. These options are not enabled until two or more Indian Country/Tribal Land search criteria are selected.
Data Quality Caveat: EPA makes no claims regarding the accuracy or precision of data concerning Indian country locations or tribal boundaries on the ECHO website. EPA has simply attempted to collect certain readily available information relating to Indian country locations. Questions concerning data should be referred to the originating program or Agency which can be identified in the Envirofacts tribal query metadata files Lower 48 Tribal Areas, Alaska Reservation, Alaska Native Villages, or Alaska Native Allotments. The Indian country and tribal boundary locations are suitable only for general spatial reference and do not necessarily reflect EPA's position on any Indian country locations or tribal boundaries or the land status of any specific location. The inclusion of Indian country information on the ECHO website does not represent any final EPA action addressing Indian country locations or boundaries. This information cannot be relied upon to create any rights, substantive or procedural, enforceable by any party in litigation with the United States or third parties. EPA reserves the right to change information on ECHO at any time without public notice.
EPA uses the U.S. Census Bureau 2016 tribal boundary layer data when developing environmental data query responses for tribes in the lower 48 United States and the Bureau of Land Management Alaska State Office when developing environmental data query responses for tribes in Alaska. EPA seeks to use the best available national federal data and may refine the tribal boundary layer in the future as more accurate national federal data becomes available.
Monitored Concentrations
Search for stations based on ambient air pollution data for criteria air pollutants in the Air Quality System (AQS).
Search for stations by the calendar year of ambient air pollutant measurements, up to the last ten individual reporting years or within the last 5 or 10 years. The most recent year of data is selected by default.
Search for stations by the particular pollutant monitored. This criterion is required to run a search. The dropdown menu lists the criteria pollutants as defined by NAAQS in the Clean Air Act:
- Carbon Monoxide
- Lead Compounds
- Nitrogen Dioxide
- Ozone
- PM, 2.5 micros
- PM, 10 microns
- Sulfur Dioxide
This allows you to choose a specific Pollutant Standard. This filters on air monitoring stations that monitor for the selected standard.
This allows you to select only the Primary standard, only the Secondary standard, or not specify by selecting "No Restrictions". EPA established the following criteria to define the two standards:
- Primary standards provide public health protection, including protecting the health of "sensitive" populations such as asthmatics, children, and the elderly.
- Secondary standards provide public welfare protection, including protection against decreased visibility and damage to animals, crops, vegetation, and buildings.
Search for air monitoring stations with increasing or decreasing concentrations of any (selected) criteria pollutant.
"No Restrictions" is the default value. Selecting "Below" excludes monitors that have a non-zero measured value for the NAAQ Standard. Selecting "Above" excludes values that are below the equal to or below the NAAQ Standard for the pollutant.
"No Restrictions" is the default value. Selecting any of the other options filters monitors with exceedances for the selected pollutant standard and timeframe.