The smell of chlorine around a pool is usually accompanied by irritation to the eyes, nose, lungs and skin of the swimmers. The pool smell is not due to chlorine but to chloramines, chemical compounds that build up in pool water when there is not enough free chlorine.
Chloramines are the result of two ingredients:
- chlorine and
- sweat, oils or urine that are brought into the pool by the swimmers.
Chlorine disinfectants are added to pool water to destroy germs that can cause illness. Sweat, oils and urine are unwanted additions to pool water. Showering before swimming can help minimize the formation of chloramines and the smelly pool.
The Chemistry of Chloramines
When chlorine disinfectants are added to water, two chemicals are formed: hypochlorous acid and hypochlorite ion. Hypochlorous acid is known as “free available chlorine” or FAC and has the potential to destroy waterborne germs. Pool operators manage the FAC level of pool water for the safety of swimmers. Free available chlorine is reduced when it reacts with swimmer waste to form these smelly chloramines.
Swimmers with red, irritated eyes complain that there is too much chlorine in the pool. When pool water is irritating, there is almost always not enough free chlorine in the pool water.
Chloramines, which produce the typical pool smell, can be destroyed using chlorine or non-chlorine shocks. A shock treatment destroys the ammonia and organic compounds that combine with chlorine to make chloramines.