2.4.1 A Simple Industrial Source Application
For this simple tutorial, an application is selected involving a single point source of SO2 that is subject to the influences of building downwash. The source consists of a 35‑meter stack with a buoyant release that is adjacent to a building. We will assume that the stack is situated in a rural setting with relatively flat terrain within 50 kilometers of the plant. A polar receptor network will be placed around the stack location to identify areas of maximum impact.
2.4.2 Selecting Modeling Options ‑ CO Pathway
The modeling options are input to the model on the Control pathway. The mandatory keywords for the CO pathway are listed below. A complete listing of all keywords is provided in Appendix B.
STARTING ‑ Indicates the beginning of inputs for the pathway; this keyword is mandatory on each of the pathways.
TITLEONE ‑ A user‑specified title line (up to 68 characters) that will appear on each page of the printed output file (an optional second title line is also available with the keyword TITLETWO).
MODELOPT ‑ Controls the modeling options selected for a particular run through a series of secondary keywords.
AVERTIME ‑ Identifies the averaging periods to be calculated for a particular run.
POLLUTID ‑ Identifies the type of pollutant being modeled. At the present time, this option only influences the results if SO2 is modeled with urban dispersion in the regulatory default mode, when a half‑life of 4 hours is used to model exponential decay.
RUNORNOT ‑ A special keyword that tells the model whether to run the full model executions or not. If the user selects not to run, then the runstream setup file will be processed and any input errors reported, but no dispersion calculations will be made.
FINISHED ‑ Indicates that the user is finished with the inputs for this pathway; this keyword is also mandatory on each of the other pathways.
The first two keywords are fairly self‑explanatory. As discussed above in Section 2.2, the MODELOPT keyword on the CO pathway is pivotal to controlling the modeling options used for a particular run. For this example, we intend to use the regulatory default options, so we will include the "DFAULT" keyword on our MODELOPT input image. We also need to identify whether the source being modeled is in a rural or an urban environment (see Section 8.2.8 of the Guideline on Air Quality Models for a discussion of rural/urban determinations). For this example we are assuming that the facility is in a rural setting. We also need to identify on this input image whether we want the model to calculate concentration values or deposition values. For this example, we are calculating concentration values. After the first three input records our input file will look something like this:
101 - 102 - 103 - 104 - 105 - 106 - 107 - 108 - 109 - 110 - 111 - 112 - 113 - 114 - 115 - 116 - 117 - 118 - 119 - 120 - 121 - 122 - 123 - 124 - 125 - 126 - 127 - 128 - 129 - 130 - 131 - 132 - 133 - 134 - 135 - 136 - 137 - 138 - 139 - 140 - 141 - 142 - 143 - 144 - 145 - 146 - 147 - 148 - 149 - 150
APLICACIONES castellano: DIS CUS DES RAD english: DIS CUS DES RAD
português: DIS CUS DES RAD italiano: DIS CUS DES RAD
français: DIS CUS DES RAD