Do you think you can identify a well‑disinfected pool by its strong chlorine smell? Classic mistake. This sharp odor is often linked to chloramines, compounds formed when chlorine reacts with sweat, urine, cosmetics, or dead skin cells. Result: burning eyes, irritated throat, a stuffy nose… and, for the most exposed, a non‑negligible respiratory risk.
Interacting chlorine in pool water
The appearance of chloramines in pools stems directly from the interaction between free chlorine—used to kill microorganisms—and organic residues brought by swimmers: urea, sweat, dead skin, but also makeup. This chemical process generates two categories of molecules: monochloramines and dichloramines, which remain dissolved in water, and trichloramines. These latter, in gaseous form, linger just above the surface because their density is higher than air, thereby polluting directly the inhalation zone of swimmers.
Breathing in trichloramines is actually particularly harsh on the body. Indeed, this gas directly attacks the cells lining the respiratory tract. During intense exercise, swimmers dilate their pulmonary capillaries and breathe mainly through the mouth, which facilitates the deep penetration of these toxic agents. This repeated exposure can permanently impair lung function, and even promote the onset of chronic bronchial conditions, with asthma at the forefront.
More Vulnerable Profiles
Major health risks primarily concern people with intensive or early exposure. Lifeguards and elite athletes are therefore the most severely affected. In fact, asthma and other respiratory disorders are frequently recognized among them as occupational illnesses or linked to intensive practice. Young children and infant swimmers are also particularly sensitive because their lungs are still developing. Early exposure can thus negatively affect their respiratory capacity in adulthood. By contrast, an occasional swimmer is not at risk of serious pathologies, but may experience temporary discomfort.
How can you tell if a pool is over-chlorinated? Several warning signs help identify an environment saturated with trichloramines. In addition to a sharp, persistent odor in the lobby, an water temperature that’s too high is a clue, as it encourages microbial growth and prompts operators to over-disinfect. On a bodily level, immediate irritations like burning eyes and a scratchy throat, or post‑swim symptoms such as a congested nose lasting for several days, indicate poor air and water quality.
What hygiene in the water?
Since chloramine production depends on the amount of organic matter introduced into the water, the responsibility for pool quality largely rests on individual behavior. It is essential to adopt strict hygiene rules before entering the water, notably by removing makeup. Also wear a swim cap and wash thoroughly under the shower to remove skin impurities. In addition, avoid swimming with wounds or illnesses. And, of course, never urinate in the water, and never use soap after swimming to preserve the skin’s hydrolipidic film, already weakened by chlorine.
The right move: before stepping into the water, take a proper soapy shower, remove makeup and cosmetics, then head to the bathroom. This small ritual reduces the organic matter in the pool and thus chloramine formation.
To keep swimming while minimizing discomfort, several solutions are available to swimmers. You can choose facilities equipped with alternative treatment systems (such as ozone or plant-based filtration) or opt for outdoor pools with better ventilation, which drastically reduce gas exposure. Likewise, favor off‑peak hours to swim in water that’s less loaded and less stirred by waves that spread toxic molecules. Finally, using simple accessories like a nose clip proves highly effective in protecting the upper airways from chemical exposure.
