What does the maximum (ensemble) average concentration represent in dispersion modeling?

The maximum (ensemble) average concentration in dispersion modeling represents the concentration for a continuous plume. This concept is crucial in understanding how pollutants disperse in the atmosphere over time. When modeling a continuous emission source, such as a manufacturing plant that continuously releases pollutants, the maximum average concentration accounts for the consistent and steady release of these emissions.

In this scenario, the model computes an average concentration that captures not just a moment in time, but rather the behavior of the pollutant as it disperses continuously over a specified period. This contrasts with transient emissions, such as puff emissions, which are brief and occur in bursts rather than continuously.

By focusing on the ensemble average concentration for a continuous plume, it provides a more reliable indication of the maximum potential exposure levels that could occur in that environment. This value is significant for risk assessments and regulatory compliance because it reflects a scenario that accounts for a constant source of emissions, which could lead to chronic exposure if not managed properly.