Trichloramine is the compound responsible for the characteristic "pool smell" — a smell most people associate with cleanliness. It is not the smell of clean water. It is the smell of chlorine reacting with urine, sweat, skin cells, and personal care products introduced by swimmers. It is a respiratory irritant, and the sharp, eye-watering sensation experienced in indoor pools is its primary health signal.
Where it's found
All chlorinated swimming pools — particularly heavily used indoor pools, resort pools, water parks with wave pools and enclosed flume rides. Produced when pool chlorine reacts with organic nitrogen from bathers.
Routes of exposure
Inhalation (primary) — volatilises at the water surface, concentrates at breathing height. Dermal absorption from pool water. Ingestion of pool water.
Health concerns
Respiratory sensitiser — linked to occupational asthma in swimming instructors, competitive swimmers, and pool lifeguards. Studies of competitive swimmers show altered lung function and elevated asthma rates. European studies have found associations between regular indoor pool attendance in childhood and increased asthma risk. At high concentrations: eye, nose, and throat irritation. The severity correlates with bather load and ventilation quality.
Evidence
Occupational asthma in pool workers confirmed as an industrial disease. Competitive swimmer lung function alterations documented in multiple studies. Bernard et al. European studies on childhood indoor pool attendance and respiratory effects. Indoor water parks measured as highest trichloramine environments accessible to the public.
Who's most at risk
Competitive swimmers (chronic high-level exposure), children (developing respiratory tracts, time spent in pools), pool workers and swimming instructors (occupational).
Regulatory status
RegulationUK/EU: water quality regulations set limits on combined chloramines in pool water. Enforcement and testing frequency variable. No specific trichloramine air quality standard for indoor pools in UK.
How to reduce your exposure
Shower thoroughly before swimming to remove sweat and personal care products — this significantly reduces precursor organic matter and trichloramine formation. Avoid heavy bather-load sessions. Outdoor pools produce far less trichloramine (UV destroys chloramines). Well-ventilated pools are materially better. For competitive swimmers: nasal breathing reduces inhalation dose compared to open-mouth breathing.
The nutrition connection
Respiratory inflammation from chronic trichloramine exposure is relevant to Nutriofia's anti-inflammatory nutrition content. Omega-3 fatty acids and antioxidant nutrients support airway health. Competitive swimmer populations have measurably altered inflammatory markers — a content angle connecting sports nutrition with chemical exposure.