This program calculates the three hour average concentration of a pollutant based on the amount produced in and around the area and on the winds that carry the pollutant in and out of the area. Any pollutant can be used, but this calculator assumes that the pollutors are fixed and constant.
Some important information about how to use this program:
The wind frequencies must be entered in decimal form, not as percentages. To help obtain meaningful results, check the Total Frequency box before running the calculations to make sure the sum of all frequencies is one.
The meteorological contants are based on experimental data gathered under varying conditions, from very unstable (Pasquill A) to very stable (Pasquill E). The meteorological section of the interface has a pop-up table of the constants a and b for different Pasquill classes. The default is Pasquill D conditions, which are relatively neutral.
The calculations assume that no pollution is produced outside the source strength grid. The size of each grid square is therefore a key component to the calculations.
The results always use the center square in the source strength grid as the receptor. The calculated concentration applies only to this square . The CijQij grid in the Results section gives the part of the one hour concentration for the receptor that is produced by each square in the grid.
Because different pollutants have different acceptable levels, you can change the environmental standard to correspond with the pollutant you are measuring.