The human nose can detect ammonia at a concentration of about 5 parts of ammonia in a million parts of air (ppm). However, prolonged exposure to ammonia can make it difficult to detect because it causes olfactory fatigue.

 The human nose can detect ammonia at a concentration of about 5 parts of ammonia in a million parts of air (ppm). However, prolonged exposure to ammonia can make it difficult to detect because it causes olfactory fatigue. 

Explanation

Ammonia is a colorless, alkaline, corrosive gas with a strong, pungent odor. 

The odor threshold for ammonia is low enough to provide a warning of its presence. 

However, ammonia can cause olfactory fatigue, making it difficult to detect when exposed for a long time. 

Exposure to ammonia can occur during accidents in transportation, manufacturing, and farming. 

Symptoms of ammonia exposure 

Irritation to the eyes, nose, and throat

Headaches

Loss of sense of smell

Nausea and vomiting

Coughing and wheezing