| Atmospheric Modeling
The Air Planning Section employs two modeling tools
which use source emissions as the focus for the analysis. The Section
utilizes the
CALPUFF dispersion modeling system for doing analyses of
Vermont sources and large sources within several hundred kilometers
of Vermont. A model called
HYSPLIT ,configured as a forward dispersion model, is used
for longer distance transport studies of very large sources that are
believed to have the potential to affect Vermont's air quality.
Another tool which is useful for identifying general
source regions that contribute to levels of air pollutants measured
in Vermont's air is the HYSPLIT model configured as a back-trajectory
model. This modeling approach identifies where air came from by calculating
backward in time from a receptor location (for instance the monitors
where air quality is measured).
Using these tools
the Section has conducted modeling studies for both criteria pollutants
and hazardous air contaminants to try to identify the amount of
transported air pollution reaching Vermont from sources outside
the state.
Meteorological modeling
tools such as MESOPAC, CALMET, RAMS, and MM5 are employed to create
the upper level wind fields that are needed for doing regional scale
modeling. The Division's activities in this area include utilizing
RAMS and MM5 output fields produced by other agencies as well as
creating meteorological wind fields in-house with models such as
MESOPAC and CALMET. These activities are critical to being able
to quantify impacts of sources located at distances greater than
30 to 50 kilometers from sensitive receptor areas.
Last Updated: 1/22/03
|
Air Pollution Control Division 
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