One factor that can change the evacuation area is:

One factor that can change the evacuation area is:

• A. A change in wind direction
• B. A change in wind speed
• C. A change in humidity
• D. A change in daylight

Answer: (A)

The main idea is that the evacuation area is set by where the hazardous release is carried by the wind. Wind direction is the factor that changes the evacuation area because it determines the direction the contaminant plume travels. If the wind shifts, the plume’s path shifts as well, which can push the danger zone into new neighborhoods or downwind areas and reduce exposure for others. Wind speed also matters because it affects how far the plume travels, but the boundary’s direction—and thus which areas must evacuate—changes most directly with wind direction. Humidity and daylight don’t directly alter the plume’s path in the way wind direction does, so they don’t change the evacuation area in the same way.

The main idea is that the evacuation area is set by where the hazardous release is carried by the wind. Wind direction is the factor that changes the evacuation area because it determines the direction the contaminant plume travels. If the wind shifts, the plume’s path shifts as well, which can push the danger zone into new neighborhoods or downwind areas and reduce exposure for others. Wind speed also matters because it affects how far the plume travels, but the boundary’s direction—and thus which areas must evacuate—changes most directly with wind direction. Humidity and daylight don’t directly alter the plume’s path in the way wind direction does, so they don’t change the evacuation area in the same way.