There’s something comforting about the smell of a chlorinated pool; most people hit the water and think that chemical smell means there can’t be any harmful pathogens living beneath the depths. The truth of the matter, however, is that a clean, healthy pool shouldn’t have a smell at all, and you shouldn’t be so thrilled about that burning sensation in your eyes.
The reason a pool smells “like chlorine” isn’t because there’s too much chlorine in it; it’s the result of chlorine mixing with various nitrogen and ammonia compounds and creating chloramines.
Chloramines, according to the Pool Center, are 60 to 80 times less effective at keeping a pool clean, but if you’re smelling a strong chemical smell already, it means your pool is already contaminated.
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While most private outdoor pools have an issue with chloramines as a result of rain water, public pools and those in hotels or other buildings get the bulk of their chloramines from human contributions.
Ammonia and nitrogen compounds are introduced into the water in the form of perspiration, urine, saliva, sputum and fecal matter from swimmers and bathers; an active swimmer sweats one pint per hour, while the average person sweats three pints per hour in a heated spa.
That’s not to mention all the other bodily fluids that contribute to producing chloramines.
Chloramines are also the compounds responsible for the sensation of burning eyes while swimming in a pool. If you’re swimming and your eyes burn, it’s because there are too many chloramines in the water, thus too many compounds that make chloramines (fecal matter, urine, sweat).
What does this mean for your health?
While chloramines themselves may cause mild irritation, the real health risk of having these compounds has to do with the level of free chlorine in a pool. If the chlorine in the water has been taken up by the chloramine process, there is likely not enough free chlorine in the pool to protect against the dangerous pathogens we really need shielding from.
Swimming in a strong-smelling pool–or one that has algae–means the chlorination process has ground to a halt. You are are no safer swimming in this kind of water than you are swimming in your local creek, and sometimes you are even more at-risk in a heated, poorly-chlorinated pool.
The International Association of Certified Home Inspectors indicates pools without proper chlorination often harbor:
- Hepatitis A and noroviruses.
- Protozoa, such as cryptosporidium (which causes diarrhea), and giardia, also known for its severe gastrointestinal effects. Some of these pathogens are highly resistant to chlorine and can survive for days in typical chlorine concentrations.
- Bacteria, such as E. coli, shigella (which causes dysentery), campylobacter and salmonella. Bacteria are generally killed quickly by chlorine disinfectant in properly maintained swimming pools at a concentration of 1 part per million. E. coli, for instance, will be inactivated in less than one minute if exposed to typical disinfectant concentrations.
So what’s to be done?
For a private pool, experts indicate more chlorine needs to be added to the water until it reaches breakpoint chlorination, where the molecular combination of chlorine and nitrogen [or ammonia] will be removed. This often requires the assistance of a professional to make sure pool chemical levels are optimal.
For people swimming in public pools, the safest bet is to shower before and, of course, after using the pool.
“If we don’t shower before we get in the water, we’re going to carry in whatever’s sitting on our skin,” says Michele Hlavsa, RN, MPH, from the CDC to the Huffington Post. “We’ve forgotten how important chlorine is in keeping us safe from germs in the water,” she said. “We have to keep in mind that it’s really important to shower before we go into the water so we leave more chlorine in the water to kill germs.”