Toxic Release Alert & Evacuation Race

A ground-level hazmat leak disperses downwind through a real Gaussian-plume model while a city grid of population blocks either gets evacuated in time or falls inside the AEGL-2 hazard envelope — depending purely on which arrives first at each block: the siren-driven evacuation order or the toxic plume front. Pick chlorine, ammonia or hydrogen sulfide, tune the wind speed and Pasquill atmospheric-stability class that shape the plume's spread, and dial in the interagency coordination lag before the alert goes out, then watch the hazard zone, the safely-evacuated population and the exposed population update live as the simulated clock runs.