Centers for Disease Control and Prevention HELIX-Atlanta Project

Led by the Centers for Disease Control and Prevention, NASA/MSFC and other partners (Federal, state, local, and academic) have joined to create Health and Environment Linked for Information Exchange, Atlanta (HELIX-Atlanta).

Part of the National Environmental Public Health Tracking Program, National Center for Environmental Health within CDC, this is creating a public health surveillance system, a bridge between health and the environment.

Health and Environment Linked for Information eXchange (HELIX)-Atlanta was a pilot linking project in Atlanta developed to support current and future state and local EPHT programs to implement data linking demonstration projects that could be part of the Environmental Public Health Tracking Network (EPHTN).

Proving the feasibility of the approach was the main objective.


  • Provide information regarding the 5-county Atlanta Area: Clayton, Cobb, DeKalb, Fulton and Gwinnett
  • Integrate environment & public health data into a local network that is part of a national network
  • Take action to prevent & control environmentally-related health effects

Data from scattered EPA monitoring sites were used to make daily surfaces of PM2.5 concentrations. High concentrations of PM2.5 are associated with adverse health reactions, e.g. respiratory and cardio-vascular problems.

Surface measurements from EPA’s Air Quality System (AQS) network are made at frequencies ranging from hourly to every 6 days. This figure shows the location of all sites within the HELIX study area.

Aerosol Optical Depth measurements from NASA’s Moderate Resolution Imaging Spectrometer (MODIS) provide a means to estimate ground-level PM2.5. The spatial coverage of the 10 km gridded MODIS data is much better than provided by the AQS surface network. MODIS data are available twice per day, but are not available when skies are cloudy.

Shows the root mean square errors, at the location of AQS measurement sites, in PM2.5 estimated from MODIS data.

Shows the 2003 annual mean PM2.5 over the study area obtained by applying a B-spline surface algorithm for each day of the year.

Focus Areas

  • Birth Defects - Integrate data for air & birth defects
  • Developmental Disabilities & Lead - Integrate data for housing age, blood lead biomonitoring, & developmental disabilities
  • Cancer - Integrate data from traffic & childhood cancers
  • Asthma - Select a standardized classification system & evaluate existing data sources
  • Water - Identify data gaps & strengths

Applications of NASA Technology

The use of NASA technology creates value – added geospatial products from existing environmental data sources to facilitate public health linkages. MODIS data will also be combined in the future with the EPA data. Additional environmental and technology data products, such as ozone and surface temperature, are being developed to provide information to the national Environmental Public Health Tracking Network (EPHTN).

Relating AQS ground-based PM2.5 to MODIS Aerosol Optical Depth measurements:
Year MODIS-Terra MODIS-Aqua
2000 0.579  
2001 0.643  
2002 0.559 0.401
2003 0.661 0.727
Correlations between daily AQS PM2.5 and MODIS AOD for April-September by year and satellite platform for 5 Metro Atlanta sites

Additional Information

National EPHT Program (
Dale Quattrochi (
Doug Rickman (
Solomon Pollard(

Presentations & Publications

Use of Satellite Remote Sensing for Public Health Applications: The HELIX-Atlanta Experience (Powerpoint File)

Linking Astma Exacerbation and Air Pollution Data     abstract

Utility of MODIS Aerosol Optical Depth for Estimating PM2.5 Exposure in Public Health Surveillance     abstract

HELIX Atlanta    abstract

Technical Contact: Dr. Dale Quattroci (
Responsible Official: Dr. James L. Smoot (
Page Curator: Diane Samuelson (