What is the strong odor associated with hydrogen sulfide (H2S)?

The strong odor associated with hydrogen sulfide (H2S) is famously described as that of rotten eggs. This distinctive smell arises because hydrogen sulfide is a byproduct of the decomposition of organic matter, particularly in environments with low oxygen levels, such as sewers, swamps, and some industrial processes. This characteristic odor is significant not just for its repulsion, but also as a warning sign of the gas's presence, which can be hazardous. Understanding this association is crucial for safety in environments where H2S might be encountered, as it can indicate potential danger due to the gas's toxicity at certain concentrations.