Central Campus Air Quality Model (CCAQM) Instructions
Model
Output
The C4$.dat
file displays all specified input data, in addition to modeled
concentration data at each receptor. Listed are contributions to
pollutant concentrations from each link (road) at each receptor.
The column “Pred Conc” lists the predicted concentration in parts
per million (ppm) at the given receptor including the ambient
concentration of the pollutant. This is the value we are most
interested in.
Interpretation of Data
Although
the
CALINE 4 model was developed for modeling CO emissions from
vehicles, by assuming all of the air pollutants emitted from
vehicles (CO, NO_{x}, HC) are conservative (nonreactive) within a
relatively short time period, we can extrapolate the model to apply
to all of these air pollutants. This assumption can be made because the
central campus area is relatively small, these pollutants are
assumed to be conservative, and they all have molecular weights on
the same order of magnitude.
This does introduce slight
uncertainty, since the force due to gravity acting on compounds with
differing molecular weights will not be the same. However, the
model assumes a settling velocity of zero, so the pollutants are
assumed to be moving relatively steadily with the mean wind.
This assumption is reasonable for the gases used in this module
since they are relatively light. If we were to consider
particulate matter, which has greater mass, this assumption would
not be as reasonable since gravitational setting would occur at a
significant rate.
