Hydrogen sulfide, known for its toxic properties, is as deadly as cyanide when compared on a molecular level. This dangerous characteristic may be the reason why humans have developed an acute sensitivity to the scent of this gas. The ability to detect its odor serves as an important survival mechanism, alerting us to potential danger in our environment.

Mary Roach's book, "Gulp: Adventures on the Alimentary Canal," delves into the fascinating aspects of human biology and evolution, highlighting how our sensory perceptions are finely tuned to protect us from harmful substances. Understanding the perilous nature of hydrogen sulfide emphasizes the importance of our olfactory senses in navigating the world safely.