Which release type is characterized by a quick, broad dispersion forming a hemispheric pattern?

• A. Hemispheric Release
• B. Cloud
• C. Puff Release
• D. Ongoing Release

Answer: (A)

When a release comes from a single point and occurs essentially instantaneously, the gas expands rapidly in all directions. Because the ground acts as a boundary, the expanding gas forms roughly a hemisphere above the surface, spreading out in a quick, broad pattern around the source. This is what the term hemispheric release describes. Other patterns reflect different release dynamics: a cloud is shaped and carried by wind into a sweeping plume, a puff is a short, finite burst that creates a rapidly enlarging blob rather than a half-sphere, and an ongoing release produces a continuous plume downwind rather than a quick, global spread.