Algorithms and Environmental Engineering - Mathematics and Statistics for the Environment - page 94

(B)

(A)

FIGURE 4.1 Traveling Salesman problem.

4.5 ENVIRONMENTAL PRACTICE ALGORITHM APPLICATIONS
Although algorithms can be used in transportation applications (e.g., Traveling Salesman prob-
lem), many of their most important applications are in environmental engineering functions. For
example, consider a robot arm assigned to weld all the metal parts on an automobile in an assem-
bly line. The shortest path that visits each weld point exactly once would be the most efficient one
for the robot. A similar application arises in minimizing the amount of time taken by a design
engineer or draftsperson to draw a given structure. Algorithms have found widespread application
in all branches of environmental practice. In environmental engineering, for example, the U.S.
Environmental Protection Agency (USEPA) uses computer models relying upon various algorithms
to monitor chemical spill and ultimate fate data. In the following, we provide selected model sum-
mary descriptions of applications used in dispersion modeling. Specifically, we discuss how the
USEPA (and others) employ preferred or recommended models (i.e., refined models that are rec-
ommended for a specific type of regulatory application) in monitoring air quality (i.e., ambient
pollutant concentrations and their temporal and spatial distribution). Further information on this
important topic can be found at USEPA (2003).

4.6 DISPERSION MODELS *
• BLP (buoyant line and point source model) is a Gaussian plume dispersion model designed
to handle unique modeling problems associated with aluminum reduction plants and other
industrial sources where plume rise and downwash effects from stationary line sources are
important.
• CALINE3 is a steady-state Gaussian dispersion model designed to determine air pollution
concentrations at receptor locations downwind of “at-grade,” fill,” “bridge,” and “cut sec-
tion” highways located in relatively uncomplicated terrain.
• CALPUFF is a multi-layer, multi-species, non-steady-state puff dispersion model that simu-
lates the effects of time- and space-varying meteorological conditions on pollution transport,
transformation, and removal. CALPUFF can be applied on scales of tens to hundreds of
kilometers. It includes algorithms for subgrid scale effects (such as terrain impingement), as
well as longer range effects (such as pollutant removal due to wet scavanging and dry depo-
sition, chemical transformation, and visibility effects of particulate matter concentrations).

* The algorithm-based models described in this section are currently listed in Appendix A of the Guidelines on Air Quality
Models (Appendix W of 40 CFR Part 51).