Mercaptan odorization threshold for gas detection in air is typically around what concentration?

Mercaptan odorization threshold for gas detection in air is typically around what concentration?

• A. 0.1%
• B. 2%
• C. 0.5%
• D. 5%

Answer: (C)

The key idea is how much mercaptan-smelling compound must be present in air for most people to notice its odor. Gas is odorized so that a detectable smell appears at a concentration well below the flammable range, giving early warning. For mercaptans used in natural gas, the typical odorization threshold in air is about 0.5% by volume (roughly 5,000 parts per million). This level is chosen because it is high enough to be reliably detected by most people, yet well below the lower explosive limit of methane (about 5%), providing a safe margin. Individual sensitivity varies, and environmental factors can affect detection, but 0.5% by volume is a standard reference point for practical odorization.

The key idea is how much mercaptan-smelling compound must be present in air for most people to notice its odor. Gas is odorized so that a detectable smell appears at a concentration well below the flammable range, giving early warning. For mercaptans used in natural gas, the typical odorization threshold in air is about 0.5% by volume (roughly 5,000 parts per million). This level is chosen because it is high enough to be reliably detected by most people, yet well below the lower explosive limit of methane (about 5%), providing a safe margin. Individual sensitivity varies, and environmental factors can affect detection, but 0.5% by volume is a standard reference point for practical odorization.