Technician deploying tracer sampler in New York City (Photo: NOAA)
The Atmospheric Tracer Technology, employed by the Air Resources
Laboratory (ARL) Field Research Division (FRD), involves a small amount
of a stable, non-toxic, invisible, odorless, and easily detectable
substance (known as a tracer) that is released into the air. The air in
the surrounding area is then sampled and the concentration of the
tracer is measured. By combining the concentrations with meteorological
information, ARL scientists can develop and test theories and models of
atmospheric transport and dispersion. Current capabilities include
continuous analyzers, time integrated sampling, and automated tracer
release mechanisms.
What It Is Used For?
ARL's Atmospheric Tracer Technology provides data neccesary to
develop, test, and improve dispersion models and air quality monitoring
systems. Atmospheric dispersion models are primary tools used by
emergency managers and first responders to determine appropriate
responses (e.g., approach routes, evacuation routes, shelter inplace)
to chemical, biological, and nuclear accidents or incidents. Dispersion
models also are used by regulatory agencies to determine appropriate
pollutant emissions controls. Dispersion models must be tested
(validated) with "real data" to detemine their accuracy. Since actual
toxic materials cannot be released into the atmosphere, surrogate
benign material (tracers) that mimic a real threat, such as those
described here, are used instead.
Why It Is Important?
Understanding how the atmosphere
transports and disperses materials released into the air is essential to
understanding and dealing with important problems such as air pollution
or the accidental (or intentional) release of hazardous material. For
example, Homeland Security experts now envision terrorist threat
scenarios whereby chemical, biological, and nuclear weapons are used in
densely populated urban centers for maximum impact. Atmospheric tracer
experiments yield a host of critical information that are then used to
determine chronic and acute exposure risks to humans, if such an
event should occur.