Air Monitoring Station Search Criteria Help - HAPs

Search Type

Specify a search type and/or choose to go directly to a nationwide map of ambient monitoring stations.

Choose a Search Type 

Choose to either search for monitors measuring hazardous air pollutants or criteria air pollutants. The search criteria in latter sections of the search form will change depending on this selection. To learn about searching for CAP monitors, see Air Monitoring Station Search Criteria Help - CAPs.

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Geographic Location 

Search for monitoring stations based on their location in the Ambient Monitoring Archive (AMA). Narrow search results based on ZIP Code, EPA Region, State, City, and County.

Air Monitoring Station Latitude/Longitude 

Search for air monitoring stations near a specific latitude and longitude. ECHO allows you to search on latitude/longitude in multiple ways: 

• Enter a valid latitude and longitude into the text box.
• Select "Use My Location" to auto populate the latitude and longitude fields based on your current location. To use this functionality, please allow ECHO permission to track your location through your internet browser.
• Latitude/Longitude Lookup - Search for latitude/longitude by address, city, country or location name.

Latitude/Longitude Search Radius 

Specify the search radius for a given latitude/longitude. Selection must be made in conjunction with the "Air Monitoring Station Latitude/Longitude" criteria. "1 mile" is selected by default.

ZIP Code 

Enter up to a five-digit ZIP code. Entering a partial ZIP code results with any ZIP beginning with the entry. You may not combine a ZIP Code search with a region search. It is recommended that you not combine a ZIP code search with a city or state search. Click the Add More button to add a value to the Selected Search Criteria panel and clear the input field for a new value.

EPA Region 

Use to search for information in a particular EPA Region. Choose a region from the dropdown menu. You may not combine an EPA Region search with a city/state, state, or RPO search. Users cannot select both an EPA Region and state.

Regional Planning Organization (RPO) 

Search for information 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 (MANE - VU), and
• Visibility Improvement State and Tribal Association of the Southeast (VISTAS).

You may not combine a RPO search with a city/state, state, or region search.

State 

Choose a state from the dropdown menu. Hold down the CTRL key to select multiple states. You may not combine a state search with a region or RPO search.

County 

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. Hold down the CTRL key to select multiple counties. You may not combine a county search with a region or RPO search.

City 

Use to search for information in a particular city. Be sure to try all possible variations and alternate spellings (e.g., try both Saint Louis and St. Louis). To search for stations in a particular city, you must also specify a state using the State dropdown menu.

Located on Tribal Land 

Search for stations that are located on or near tribal land. Search is based on EPA comparison of the facility 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 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.

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.

 

Location Type 

Search for air monitors based on a location's population density and land use.

Monitored Location within 5km of RCRA LQG or TSDF  

"No Restrictions" is selected by default. Select “Yes” to restrict to locations within 5km of RCRA LQG or TSDF or “No” to exclude locations within 5km of RCRA LQG or TSDF.

AMA Site Code 

Use to search for stations based on unique Ambient Monitoring Archive (AMA) site codes. You can search for multiple IDs by using a comma-separated list. 

Nonattainment Area  

Search for stations that are in a nonattainment 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. Note that specific nonattainment severity options are not currently available.

Pollutant Emissions Correspond to Nonattainment 

“Any” is selected by default and places no restrictions on the search. Select “Yes” to identify stations that are in a nonattainment area or “No” to exclude stations that are in a nonattainment area.

Population Density Greater than (per sq. mile) 

Identify stations within high or low density areas according to the 2010 U.S. Census data. Enter a value for total number of persons per land area (square miles).

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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.

Compare To 

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.

Based On 

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.

Index Type 

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.

Count of Indexes 

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.

Percent Low Income (3-mile radius) 

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

ICIS Tribal Land Flag 

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.

FRS Tribal Land Code 

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.

On or Near Spatial Tribal Boundary 

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

Tribes 

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.

Indian Country/Tribal Land, Find Stations that Match 

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.

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Monitored Risk Level 

Ambient Air Quality Monitoring  - Search by the pollutants monitored at air quality monitoring stations and associated hazard criteria.

 

Choose a Timeframe 

Search for stations by the year of ambient pollutant measurements, up to the last ten reporting years. Displays results for the chosen timeframe, either between the last 10 years, Last 5 years, or any individual year up to 2008. "Last ten years" is selected by default.

"Define Year As" allows you to select either Best Rolling 12 Months of Data or Calendar Year. Cancer and hazard risks are calculated based on the assumption of continued, long-term exposure. Therefore, it may be misleading to present cancer or hazard risks if a monitor only has readings for part of the year. EPA has established the following criteria to select the Best Rolling 12 Months of Data to represent annual concentrations:

• The annual dataset must comprise at least 3 valid quarters of data; and
• Valid quarters must have at least 70% of expected measurements for a pollutant (so if measurements are daily, then ~63 out of 90 measurements in a quarter.)

See the Air Monitoring Station Data Rules and Calculations page for more information.

Pollutant Name 

Search for monitors by a particular pollutant(s). Enter at least one character. Select a pollutant from the dropdown list to add it to the search criteria selected panel and clear the input field for a new value. "Any Specific Pollutant" does not restrict results. This selection can not be combined with CAS Number.

Chemical Abstract Service (CAS) Number 

A Chemical Abstract Service (CAS) number is a number assigned by the American Chemical Society that uniquely identifies a chemical. Click the Add More button to add a value to the Selected Search Criteria panel and clear the input field for a new value, or separate multiple CAS Numbers by commas. This selection can not be combined with Pollutant Name.

 

Air Concentration Trend 

Search for stations with increasing or decreasing concentrations of any (selected) pollutant. 

Average Long Term Cancer Risk Level (in a million) 

Search for monitors exceeding the selected long-term cancer risk level (number of people in a million). A risk level of “N”-in-1 million implies a likelihood that up to “N” people, out of one million equally exposed people would contract cancer if exposed continuously (24 hours per day) to the specific average concentration over 70 years (an assumed lifetime). This would be in addition to those cancer cases that would normally occur in an unexposed population of one million people.

When the pollutant selected is "Aggregate Pollutants" this searches for the cumulative risk for all monitored pollutants at a station. This search option allows users to identify areas of potential cancer risk and is not intended to provide a comparison between stations, as stations may monitor for different numbers and types of pollutants.

Hazard Quotient Level 

Search for monitors measuring air pollutant concentrations exceeding a specific hazard quotient level. Select a specific target organ or organ system and a hazard quotient level of 1, 2, 10, 25, 50 or 100. Hazard quotient indicates the ratio of the potential exposure to an air pollutant and the level at which no adverse effects are expected. A hazard quotient less than or equal to 1 indicates that adverse effects are not likely to occur, and thus can be considered to have negligible hazard.

Compare to Modeled Ambient Concentrations 

Select "Yes" to compare the monitored pollutant concentrations to AirToxScreen modeled pollutant concentrations.

75% of ambient daily average measurements reported are >= ___ times the modeled values allows you to select a multiplier number if "Yes" is selected for Compare to Modeled Ambient Concentrations.

Set Non-Detects Equal To 

When a pollutant concentration is reported as "not detected," its actual concentration may be zero or some value between zero and the detection limit. The user can choose to calculate the average pollutant concentration using one of three methods: setting all non-detects to zero, setting all non-detects to ½ the detection limit, or using the regression method. By default, non-detects are set to use regression method. See the Air Monitoring Station Data Rules and Calculations page for more information. 

Exclude Results with More Than 80% Non-Detects 

Select this checkbox to exclude stations with 80% or greater non-detect pollutant measurements during the selected timeframe.

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Modeled Risk Screening 

Search for Air Monitoring Stations located within a census tract with air quality meeting certain AirToxScreen modeled risk or hazard levels. 

AirToxScreen  is EPA's comprehensive evaluation of air toxics in the United States, based on modeled air quality. These activities include the expansion of air toxics monitoring, improvement and periodic updating of emission inventories, improvement of national- and local-scale modeling, continued research on health effects and exposures to both ambient and indoor air, and improvement of assessment tools. AirToxScreen provides a snapshot of the outdoor air quality and the risks to human health that would result if air toxic emission levels remained unchanged. More information on AirToxScreen can be found on the EPA AirToxScreen Frequently Asked Questions page.

AirToxScreen Long-Term Cancer Risk Level (in a million) 

A risk level of “N”-in-1 million implies a likelihood that up to “N” people, out of one million equally exposed people would contract cancer if exposed continuously (24 hours per day) to the specific concentration over 70 years (an assumed lifetime). This would be in addition to those cancer cases that would normally occur in an unexposed population of one million people. Note that this assessment looks at lifetime cancer risks, which should not be confused with or compared to annual cancer risk estimates. If you would like to compare an annual cancer risk estimate with the results in this assessment, you would need to multiply that annual estimate by a factor of 70 or alternatively divide the lifetime risk by a factor of 70. More information on AirToxScreen Long-Term Cancer Risk Level can be found on the AirToxScreen Glossary of Terms

Select a Cancer Risk and risk level. Then select a Pollutant through the lookup. For example, searching on "Background > 25" and "Formaldehyde" will return ambient emission stations where the cancer risk level for the pollutant is greater than 25 in 1 million.

 

AirToxScreen Hazard Quotient Level 

The ratio of the potential exposure to the substance and the level at which no adverse effects are expected. A hazard quotient less than or equal to one indicates that adverse non-cancer effects are not likely to occur, and thus can be considered to have negligible hazard. HQs greater than one are not statistical probabilities of harm occurring. Instead, they are a simple statement of whether (and by how much) an exposure concentration exceeds the reference concentration (RfC). Moreover, the level of concern does not increase linearly or to the same extent as HQs increase above one for different chemicals because RfCs do not generally have equal accuracy or precision and are generally not based on the same severity of effect. Thus, we can only say that with exposures increasingly greater than the RfC, (i.e., HQs increasingly greater than 1), the potential for adverse effects increases, but we do not know by how much. An HQ of 100 does not mean that the hazard is 10 times greater than an HQ of 10. Also an HQ of 10 for one substance may not have the same meaning (in terms of hazard) as another substance resulting in the same HQ. More information on AirToxScreen Hazard Quotient Level can be found on the AirToxScreen Glossary of Terms

Select a Target System and hazard index value. Then Pollutant search options are restricted depending on Target System selection. For example, selecting Target System "Respiratory >= 2" will restrict Pollutant search options. "Respiratory >= 2" will return ambient emission stations where the exposure concentration exceeds the reference concentration by 2.

AirToxScreen Hazard Index Level 

The sum of hazard quotients for substances that affect the same target organ or organ system. The hazard index (HI) is only an approximation of the aggregate effect on the target organ (e.g., the lungs) because some of the substances might cause irritation by different (i.e., non-additive) mechanisms. As with the hazard quotient, aggregate exposures below an HI of 1.0 derived using target organ specific hazard quotients likely will not result in adverse non-cancer health effects over a lifetime of exposure and would ordinarily be considered acceptable. An HI equal to or greater than 1.0, however, does not necessarily suggest a likelihood of adverse effects. Because of the inherent conservatism of the reference concentration (RfC) methodology, the acceptability of exceedances must be evaluated on a case-by-case basis, considering such factors as the confidence level of the assessment, the size of the uncertainty factors used, the slope of the dose-response curve, the magnitude of the exceedance, and the number or types of people exposed at various levels above the RfC. Furthermore, the HI cannot be translated to a probability that adverse effects will occur, and it is not likely to be proportional to risk. More information on AirToxScreen Hazard Index Level can be found on the AirToxScreen Glossary of Terms

Select a Target System and a hazard index value. For example, searching on "Respiratory System > 2" will return the ambient monitoring stations located in areas where the hazard index level is greater than 2.