Air Pollution & Air Quality

National Atmospheric Release Advisory Center

The National Atmospheric Release Advisory Center (NARAC) is a national support and resource center for planning, real-time assessment, emergency management, and detailed studies of incidents involving a wide variety of hazards, including nuclear, radiological, chemical, biological, and natural emissions.[1][2]

NARAC is a part of the Lawrence Livermore National Laboratory (LLNL)[3] which is a premier applied science laboratory that is part of the National Nuclear Security Administration (NNSA)[4] within the U.S. Department of Energy (DOE).

NARAC's primary functions

NARAC's primary function is to support U.S. Department of Energy and U.S. Department of Defense sites, and DOE consequence management (CM) teams for radiological releases through the DOE's Atmospheric Release Advisory Capability (ARAC)[5] program. Under the auspices of the National Response Framework, NARAC assists other federal agencies and, through them, state and local agencies. NARAC's support and advisory responsibilities are implemented by:

  • Providing tools and services that map the probable spread of hazardous material accidentally or intentionally released into the atmosphere.
  • Providing atmospheric plume predictions in time for an emergency manager to decide if action is necessary to protect the health and safety of people in affected areas.

Location and operational facilities

NARAC is located at the Lawrence Livermore National Laboratory in Livermore, California (about 50 miles east of San Francisco).

The operational facilities operated by NARAC include:

  • A team of research and operational staff with expertise in atmospheric research, operational meteorology, numerical modeling, computer science, software engineering, geographical information systems, computer graphics and hazardous material (radiological, chemical, biological) properties and effects.
  • An operations center with uninterruptible power, backup power generators, robust computer systems and a staff on-duty or on-call 24 hours per day and seven days a week.
  • Scientific and technical staff who provide support and training for NARAC tools, as well as quality assurance and detailed analysis of atmospheric releases.
  • Links to over 100 emergency operations centers around the United States.

To provide integrated emergency response support, NARAC collaborates with more than 300 federal, state, and local agencies and emergency operations centers. The center’s operational system responds to about 7000 requests per year and has over 1800 online users.[6]

The Emergency Response System

NARAC maintains a sophisticated Emergency Response System at its LLNL facility. The NARAC emergency response central modeling system provides real time atmospheric dispersion modeling[7][8] using an integrated suite of meteorological and atmospheric dispersion models.[9]

NARAC clients access this system using software supplied by NARAC. With this system NARAC provides an automated product report for almost any type of hazardous atmospheric release anywhere in the world within five to ten minutes.[9]

When a client initiates a request via a phone call or interactively using the NARAC-supplied software online, the automated steps taken by the Emergency Response System are summarized below:[9][10]

  • Receive and process information about the hazardous release in what is called a Questionnaire.
  • Collect meteorological data for the region around the release location and time.
  • Determine additional model parameters not provided in the Questionnaire and execute the suite of sophisticated atmospheric dispersion models.
  • Generate the requested product report that depicts the size and location of the release plume, the affected population, the health risks, and the proposed emergency responses.
  • Deliver the report to the client using the Internet, fax, or e-mail.


  1. About NARAC: Overview, from the NARAC online website.
  2. NAREC Fact Sheet, from the NARAC online website.
  3. Lawrence Livermore National Laboratory, from the LLNL online website.
  4. NNSA website
  5. ARAC Fact Sheet, from the Department of Energy website.
  6. On the Leading Edge of Atmospheric Predictions, from the LLNL online website.
  7. D.B. Turner (1994), Workbook of atmospheric dispersion estimates: an introduction to dispersion modeling, 2nd Edition, CRC Press, ISBN 1-56670-023-X.
  8. Milton R. Beychok (2005), Fundamentals Of Stack Gas Dispersion, 4th Edition, author-published, ISBN 0-9644588-0-2.
  9. Emergency Response System: Overview, from the NARAC online website.
  10. Emergency Response System: Steps, from the NARAC online website.


Beychok, M. (2011). National Atmospheric Release Advisory Center. Retrieved from


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