🔍 Key Concepts

• Hydrogen sulfide (H₂S) behavior: heavier than air, tends to accumulate in low-lying areas • Atmospheric stability vs. mixing: stable conditions vs. windy/turbulent conditions and how they affect gas dispersion • Time of day and weather: how sun, wind, and temperature differences between ground and air affect vertical mixing

💭 Think About

• Think about when the air is most stable and least turbulent, so that a heavy gas stays concentrated instead of mixing and dispersing • Which conditions promote strong vertical mixing: sunshine, wind, or calm clear nights? Compare these effects on dispersion • Consider where H₂S will go if there is little wind and a cooler layer of air sitting close to the ground

✅ Before You Answer

• Identify which option represents stable air with minimal turbulence • Eliminate choices that clearly increase wind-driven mixing and dilution of the gas • Check which condition would allow H₂S to pool and remain concentrated near the ground rather than disperse