How does topography influence the spread of a poisonous gas that is heavier than air?

Topography can significantly influence how a heavier-than-air gas disperses in the environment. When a gas is released into the atmosphere, its behavior is affected by the surrounding landscape. In areas of varied elevation, such as hills or valleys, the movement of the gas can be altered.

In a low-lying area, for example, the gas may accumulate and spread less due to the physical barriers presented by higher ground. Conversely, in a situation where the terrain is uneven, the gas can be funneled down into valleys or depressions, potentially increasing the concentration and spread in those areas. Additionally, wind patterns influenced by topography can either dilute the gas as it moves uphill or contribute to its dispersion downwind in lower areas.

Thus, the correct response reflects the range of outcomes that can arise from the topographical features of an area. The ability of the landscape to either hinder or facilitate the spread of the gas highlights the complex interactions between gas properties and environmental conditions.