What does high vapor density indicate about a substance?

• A. It rises easily in the air
• B. It is heavier than air and sinks
• C. It is toxic
• D. It is flammable

Answer: (B)

High vapor density indicates that the substance is heavier than air, which means that when it is released into the atmosphere, it will tend to sink rather than rise. This property is crucial in understanding how hazardous materials behave in the environment, as substances with high vapor density can accumulate in low-lying areas or confined spaces, potentially leading to dangerous situations. For instance, if a gas with high vapor density leaks, it may settle in basements or ditches, making those areas hazardous to anyone present. Understanding vapor density is key for responding effectively to spills or leaks of such materials, as it allows responders to anticipate the movement of the gas and take appropriate measures to ensure safety.