Issue with Pollutant Concentration Spike in Kitchen Zone for Specific Time Period

[Mozhan Aghili]

Hello Everyone

I hope this email finds you well.

I have encountered an issue during the simulation of pollutant concentrations in the kitchen zone. The concentration spikes significantly during two specific hours of a particular day, while the rest of the year shows a nearly constant pattern. Although I defined an emission source for the pollutant during these specific two hours, this spike is not observed at other times of the year, where the concentration remains almost continuous.

I have reviewed the CTM and WTH data, as well as the input parameters for the source file, and found no discrepancies. Could you please assist in identifying why these concentration fluctuations occur only during those two hours and why they are not present during other times of the year?

Thank you very much for your support.

Best regards,

Moujan

[William Dols]

Well, I guess "constant pattern" is in the eye of the beholder.

Of course it's difficult to provide specific guidance without the input files, but I would offer the following guidance:

• Focus on one of the days in question.
• Use ContamW to investigate the airflows associated with the kitchen zone.
• Do back-of-the-envelope calculation to determine the range of expected concentration based on emission and removal rates, e.g., Css = Cambt + GenRate/FlowRate.
• It is unclear what the frequency of your results are: 
  • if your reporting frequency is to long, then you may not be capturing a very representative time history
  • set the Calculation and Output timesteps to smaller values and run the simulation to bracket the periods in question

- Stuart