Massachusetts Wastewater Practice Exam

What is the odor characteristic of pure methane gas?

1. Strong chemical odor

2. Foul rotten egg smell

3. No odor

4. Sweet fragrant smell

The correct answer is: No odor

Pure methane gas is characterized by having no odor. This is important to recognize because methane itself is a colorless and odorless gas, making it hard to detect in its natural state. To enhance safety and facilitate detection, utility companies often add odorants, like mercaptan, which give natural gas (which is primarily methane) a distinct smell, often described as similar to rotten eggs. However, when discussing pure methane specifically, there isn't an inherent scent associated with it. This characteristic makes option C the correct choice, emphasizing the need for awareness regarding gas safety and detection methods in various environments.