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RSIG Data Inventory

The RSIG applet and web servers are conduits for accessing data whose quality is the responsibility of the organizations that produce and maintain the data.

When a new dataset is added to RSIG's complement, quality checks are conducted to ensure that the data RSIG retrieves matches the data from the source files.

While data integrity checks have been performed by the RSIG team, not all data provided through RSIG has been independently quality assured by the EPA. Please direct all questions about data quality or related issues to the data source providers listed below.

Archived data may not be immediately available. Data availability depends on such factors as the remote host system's availability, the stability of network connections, and other issues beyond the control of EPA and this application. The RSIG application will display system messages if data is unavailable.

If a problem is noted concerning the integrity of any dataset, please contact the RSIG team

Air Quality System (AQS) (US EPA)

AQS contains data vetted by the states. RSIG accesses AQS data via the AQS Data Mart database. The following text is from the AQS Data Mart site:

The AQS Data Mart is a database containing all of the information from the AQS system. Since 2007, it has contained information from AIRNow (the real time air quality reporting system) that participating agencies allow to be shared with the public. Currently the AQS Data Mart has nearly 1.6 billion values-every measured, daily aggregate, and annual aggregate value collected and calculated by EPA since January 01, 1980.

The data in the AQS Data Mart is updated nightly, 5 times per week, from the AQS database so it is the latest available. Eventually it will bring in the real-time AIRNow data each night as well.

Historical data can change at any time. Many quality assurance review processes are made on an entire year's worth of data, so it might not be until the middle of this year until the final review and changes have been made to last year's data by a submitter. Also, historical monitoring or calculation methods may be found to be problematic and require that older data be changed. Finally, there is no "versioning" or freezing of data in the Data Mart, so if other people may need your data exactly as you have it to verify or continue your analysis, you must keep a copy of it.

AQS data takes precedence over AIRNow data. AIRNow data is removed after one year if the data is not updated by AQS.

The following AQS data are available: GMT hourly ozone and PM2.5, GMT daily average PM2.5, ozone GMT 8-hour average and maximum, temperature, relative humidity, sulphur dioxide from 1980 onward.

Refer to the AQS Data Mart site for more information.

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These data are archived at the AIRNow Gateway operated by Sonoma Technology for US EPA's AIRNow Program and accessed on-demand via the following web server command:

Note: To use a web service to retrieve specified data, one must append specific parameters to the end of the URL that specify the date range, parameter code, and -- in the case of Sonoma Tech -- an account key code.

The following text is from the AIRNow web site:

These data are not fully verified or validated and should be considered preliminary and subject to change. Data and information reported to AIRNow from federal, state, local and tribal agencies are for the express purpose of reporting and forecasting the Air Quality Index (AQI). As such, they should not be used to formulate or support regulation, trends, guidance, or any other government or public decision making. Official regulatory air quality data must be obtained from EPA's Air Quality System (AQS).

AIRNow data available are GMT hourly ozone and PM2.5 from 2003 onwards.

Refer to the AirNow APIEXIT for more information.

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Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) (NASA)

The following CALIPSO data are available through RSIG:
  • 2006-07-01 to present
  • Level-1b Backscatter and Depolarization
  • Level-2 Aerosol and Cloud: Backscatter, Extinction, Depolarization, Aerosol/Cloud Layer Fraction and Column Optical Depth (integrated to surface)
RSIG conservatively filters the CALIPSO data according to NASA Langley CALIPSO Team recommendations that include:
  1. Valid range of data, which can include slightly negative (non-physical) values required to avoid bias in any subsequent aggregation.
  2. Available/applicable quality control (QC) flag data (only non-error bits accepted).
  3. Available/corresponding absolute uncertainty data (user adjustable).
  4. CAD_Score (cloud-aerosol discrimination score): a measure of the likelihood of correctly distinguished aerosol/cloud features (user adjustable).
  5. Uncertainty file (if available) when saving CALIPSO data.

NASA's CALIPSO site has more information on the CALIPSO program, along with detailed data product descriptions.

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Community Multiscale Air Quality (CMAQ) Model Output (US EPA)

CMAQ model output available via RSIG includes meteorology, gridded emissions, concentrations, depositions, derived PM2.5, NOy, aerosol optical depth (AOD), and Extinction:
  • Office of Air Quality Planning & Standards (OAQPS) Centers for Disease Control (CDC) East US 12km 2002-2006 and 12km CONUS 2007-2008. Update, 11/28/2016: CMAQ CDC data is now only aconc.o3 and pm25 layer 1.
  • Atmospheric Modeling and Analysis Division (AMAD) Northern Hemisphere 2006 (restricted access). Update, 11/28/2016: CMAQ AMAD data renamed CMAQ CED (Computational Exposure Division) and expanded to years 2002-2012.
  • Metadata for 2002-2012 12km Continental US (CONUS) Bidirectional confined animal feeding operations (CAFO) CMAQ v5.0.2 Simulations
  • Metadata for 2025 12km CONUS Bidirectional-CAFO run of November 2014_v2 – CMAQv5.0.2 Simulations

Other CMAQ runs will be added as they become available for release.

Refer to the comprehensive CMAQ site for more information. 

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Fused Air Quality Surfaces Using Downscaling (FAQSD) (US EPA)

A Bayesian space-time downscaler model is based on statistical modeling research in developing fused space-time predictive surfaces for air quality.

A Bayesian space-time downscaler model is used to "fuse" daily ozone (8-hr max) and fine particulate air (24-hr average) monitoring data from the National Air Monitoring Stations/State and Local Air Monitoring Stations (NAMS/SLAMS) with 12 km gridded output from the Models-3/Community Multiscale Air Quality (CMAQ) model.

Daily predictions are available at the 2010 US Census Tract centroid locations for 2002-2012.

The FAQSD data files and metadata can be downloaded from the RSIG downloadable data files page.

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Geostationary Operational Environmental Satellite system (GOES) Aerosol Smoke Product (GASP) Aerosol Optical Depth (AOD) (NOAA)

More information on GASP data can be found at NOAA's Center for Satellite Applications and Research site.

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Moderate Resolution Imaging Spectroradiometer (MODIS) (NASA)

MODIS data includes generally available Aerosol Optical Depth (AOD), Cloud Optical Thickness (COT), ozone, pressure, and temperature from 2000 onwards. 

The MODIS products available from RSIG are (links go to a NASA page for each product):

For more information, refer to NASA's MODIS summary page

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Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC)

The following MOZAIC data is available: ozone, CO, H2O, temperature, wind, etc.: 2002-01-01 to 2011-12-31.

The Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) program was initiated in 1993 by European scientists, aircraft manufacturers, and airlines to collect experimental data. Its goal is to help understand the atmosphere and how it is changing under the influence of human activity, with particular interest in the effects of aircraft. MOZAIC consists of automatic and regular measurements of ozone and water vapor by five long range passenger airliners flying all over the world. The aim is not to detect direct effects of aircraft emissions on the ozone budget inside the air traffic corridors but to build a large database of measurements to allow studies of chemical and physical processes in the atmosphere, and hence to validate global chemistry transport models. MOZAIC data provide, in particular, detailed ozone and water vapor climatologies at 9–12 km where subsonic aircraft emit most of their exhaust and which is a very critical domain (e.g., radiatively and stratosphere/troposphere exchanges) still imperfectly described in existing models. This will be valuable to improve knowledge about the processes occurring in the upper troposphere and the lowermost stratosphere, and the model treatment of near tropopause chemistry and transport. 

Marenco, A., et al. (1998), Measurement of ozone and water vapor by Airbus in-service aircraft: The MOZAIC airborne program, an overview, J. Geophys. Res., 103(D19), 25631–25642, doi:10.1029/98JD00977.

MOZAIC has been superceded and absorbed by the In-service Aircraft for a Global Observing System (IAGOS) Data Portal Exit. You need to register on the IAGOS site to access the data.

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National Environmental Satellite, Data, and Information Service (NESDIS) Biomass Burning Data (NOAA)

From the NESDIS page, Air Quality Remote Sensing Program - Emissions Products:

Emissions from both natural and anthropogenic sources contribute to poor air quality. Biomass burning (prescribed and wild fires) release huge amounts of smoke (primary particulates dominated by black carbon) and trace gases into the atmosphere...

RSIG data includes biomass burning 2007 (PM2.5, CO, CO2, CH4, N2O, NH3, NOx, SO2, TNMHC).

The data provider is NOAA NESDIS Center for Satellite Applications and Research. Data is accessible via ftp

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NOAA-EPA Ultraviolet Brewer Spectrophotometer (NEUBrew) (NOAA, US EPA)

From the NEUBrew page:

The NOAA/EPA Brewer Spectrophotometer Network consists of six stations located in the western, central and eastern United States. Brewer instruments provide daily Ultra-Violet (UV) Radiation and Total-Column Ozone measurements. Many Brewers are co-located at NOAA SURFRAD stations equipped with Total Surface Radiation Budget instrumentation, and Total Sky Imagers

Data in RSIG are ozone (molecules/cm3) profiles (26 points up to 51 km) in the morning and evening, since September 2006.

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From the mid-1990s until 2004, EPA’s UV-Net Program operated a network of Brewer spectrophotometers throughout the United States. Ultraviolet monitoring later transitioned to the NEUBrew project.

Data are from 22 ground stations in the US measuring Irradiance (W/m2) and UVBio "sunburn" (W/m2) for the years 1996 through 2004-06.

Data is available from an archived EPA site (search on "uv net data access").​

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In-Process: Upcoming Datasets

EPA is working to bring the following additional data sets into RSIG:

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