Smell

As we age, the number of functioning smell receptors decreases and this increases the threshold for smell. It takes a more intense smell for it to be identified and differentiated from other smells. After the age of 50 the sense of smell decreases rapidly. By age 80, the sense of smell is reduced by about half. The lack of ability to smell spoiled food can lead to indigestion and food poisoning. Even more seriously, studies have show that older persons may not be able to detect relatively high levels of mercaptoethanol. This odorant is added to natural gas so that individuals can detect gas leakage. Thus older persons can miss detecting natural gas leakage at levels that could cause explosions.