### When running HYSPLIT concentrations I got 10E-11 … 10E-17 for values of concentration. I understood that the unit is mass/m3.hr. My question is that in order to apply the numbers to total emission from a power plant stack, how can I calculate real plume concentration? Suppose it is 167381 ton/yr and converted 19 ton/hr, then, can I just multiply 19 ton/hr by 10E-11… to get real level?

The simple answer is yes, just multiply the hourly emission by the concentration. However, to do this simulation requires a continuous emission. If the default run assumed a one hour emission of one unit, then the output concentrations, regardless of what true hourly rate you multiply, still only represent the emissions for one hour. The simulation must be run with a continuous emission duration (same length as the simulation) and if a unit rate (1/hr) is used for the source, then the concentrations can be multiplied by the actual average hourly emission rate to get an estimate of the true concentrations.

Glenn Rolph