Chloramines result from the combination of chlorine disinfectants and the perspiration, cosmetics, and urine that enter pools on the bodies of swimmers. Chlorine disinfectants are added to pool water to destroy germs that can give swimmers diarrhea, swimmer’s ear and athlete’s foot. Perspiration, oils and urine are unwanted additions to pool water. By showering before entering the pool to wash these substances from the skin, swimmers can help minimize pool smell.
The grass directly beneath a heavy object, such as an swimming pool filled with water, receives none. Eventually, the grass beneath the pool dies and begins to decay. When you remove the pool, the odor becomes apparent.
Reference: Wiedmer, C. et al (2017). Characterization of odorants in inflatable aquatic toys and swimming learning devices – which substances are causative for the characteristic odour and potentially harmful? Analytical and Bioanalytical Chemistry DOI: 10.1007/s00216-017-0330-x
The researchers then investigated the molecular make-up of the distinctive smells arising from the pool toys. They extracted detectable odours from each sample using solvent extraction and high vacuum distillation methods, and then identified the main odorants using a combination of sensory and common analytical approaches.
Wiedmer expressed his concern that some of the products contain potentially hazardous chemicals that could pose a risk to childrens health, depending on the degree of exposure and concentration levels in the products. Cyclohexanone can be harmful if inhaled, phenol is known to be acutely toxic and to presumably have mutagenic potential and isophorone is a category 2 carcinogen, which means that this is a suspect substance in the development of cancer in humans.
Inflatable toys and swimming aids, like bathing rings and arm bands, often have a distinctive smell which could indicate that they contain a range of potentially hazardous substances. Some of these compounds, which include carbonyl compounds, cyclohexanone, phenol and isophorone, might be critical when present in higher concentrations in childrens toys, say Christoph Wiedmer and Andrea Buettner, who are authors of a study in the journal Analytical and Bioanalytical Chemistry (ABC), which is published by Springer.
As part of the study, a panel of trained volunteers sniffed each product, and ascribed common odour attributes to these. They also rated the intensity of each odour, and had to guess whether these could be hazardous. Three of the products reminded the panellists of almonds, plastic and rubber, while the fourth more pungent one reminded them of glue and nail polish.
The Chemistry of Pool Smell
When chlorine disinfectants are added to water, they unleash two chemicals that help destroy waterborne germs: hypochlorous acid and hypochlorite ion. These two chemicals are known together as “free available chlorine” or FAC. Pool operators manage the FAC level of pool water for the safety of swimmers. Their challenge comes from the fact that FAC is reduced when it reacts with perspiration, oils and urine from swimmers to form chloramines.
One way that chloramines are formed in pool water is by the reaction of hypochlorous acid with ammonia, a component of sweat and urine. Three chemical reactions can occur when hypochlorous acid reacts with ammonia, each involving the replacement of hydrogen ions with chlorine ions. When one of ammonia’s hydrogen ions is replaced with chlorine, monochloramine is formed. Replacing one more hydrogen ion with chlorine produces dichloramine. It is also possible to replace all three of ammonia’s hydrogen ions with chlorine to form trichloramine, also known as nitrogen trichloride.
Monochloramine is sometimes intentionally added to water because it is actually a useful water disinfectant. Drinking water, for example, is sometimes purified with monochloramine. Dichloramine and especially trichloramine are the chloramines most responsible for pool smell. Showering before entering the pool can help to minimize the formation of these two chloramines.
Public Pools: Why Do they Smell Like That? | INGREDIENTS by George Zaidan
FAQ
Why does it smell like manure under my pool?
How do you get the smell out of a vinyl pool?
Why does my above-ground pool smell?
How do you get rid of dead wet grass smell?
Why does my pool smell bad?
A swimming pool not only blocks the grass from receiving sunlight, but also blocks a considerable amount of oxygen — intensifying the odor the rotting grass gives off when you remove the pool. While the decomposing grass beneath your pool gives off an unpleasant smell, you may have another odorous culprit lurking within the dead grass — mold.
Does pool water smell bad?
Pool water that smells bad can make even a clear pool appear dirty (and it likely is!). Sometimes the smell may be faint and only apparent if you’re in the water, whereas other times the smell could occupy the surrounding yard.
Why does my pool smell like grass?
While the decomposing grass beneath your pool gives off an unpleasant smell, you may have another odorous culprit lurking within the dead grass — mold. If any mold spores were present in the grass when you installed the pool, these mold spores need only food, moisture and the right temperature to grow rapidly.
Why does my pool smell like a dead animal?
Ensure that there’s not a dead animal that is decaying as this could be the source of the smell. If a nearby animal can’t be pinned to the smell, the next step is to bump up the chlorine levels in the pool to shock level.