Wastewater New York State Practice Exam

What does hydrogen sulfide at 130 ppm smell most like?

1. Strong rotten egg odor

2. Nothing due to nerve damage

3. Sweet and pleasant

4. Strong vinegar smell

The correct answer is: Nothing due to nerve damage

Hydrogen sulfide is known for its distinctive odor that is often compared to that of rotten eggs. At a concentration of 130 parts per million (ppm), individuals are likely to experience a strong and pervasive odor. While lower concentrations of hydrogen sulfide can be experienced without any immediate physical effects, exposure to high levels, such as 130 ppm, can lead to olfactory fatigue or nerve damage, which might impair a person's ability to smell it. At this concentration, it's important to note that hydrogen sulfide can be dangerous, and prolonged exposure may result in a situation where the person becomes desensitized to the smell, leading them to perceive nothing at all. It's crucial to understand that this is not because the gas lacks odor at that concentration; rather, the body's sensory response to it may diminish or fail due to the exposure. Understanding these characteristics of hydrogen sulfide is essential for safety in environments where this gas may be present, as recognition of its smell is a key element in detecting potential risks.