Find out what causes eye pain when swimming

US scientists discovered chlorine in swimming pools is not the cause of eye pain, but the main cause is urine.

Newsweek yesterday reported that the US Centers for Disease Control and Prevention (CDC) report that the cause of eye irritation is urine.

Swimming pool water contains chlorine, urine, even stool.(Photo: Reuters)

"Chlorine does not cause red eyes. It is the compounds that make up chlorine with urine, sweat and many other things we bring into the water that cause this, " said Michele Hlavsa, CDC representative.

Chlorine can combine with urine in urine to form chloramine - a derivative of ammonia. Not only does it cause redness in the eyes , these compounds can also cause people to swim with respiratory problems such as a runny nose or cough.

Even the chemical smell we often smell in swimming pools is not chlorine. The CDC report indicated that it was a mixture of urine, sweat, dirt and sometimes feces. The report also said that a completely clean swimming pool would be a pool without chemicals.

Chlorine is often put into swimming pools to kill harmful bacteria, such as E.coli bacteria that cause diarrhea. But when there is too much urine discharged in the water, chlorine will turn into chloramine and lose its bactericidal effect. Thus, bacteria survive and multiply in water.

To ensure health when swimming in the tank, CDC advises us not to swim in a cloudy pool, sniff the pool water before going down, not to swim for too long and to shower before getting into the tank.