Pool Water Quality Management: How Chlorine Concentration Affects Skin, Eyes, and Hair — and How to Protect Yourself

Introduction

The lingering chlorine smell after a swim is a familiar sensation for many swimmers — and one of the reasons some people hesitate to swim at all. Pool chlorination is one of modern public health’s great achievements, but prolonged exposure to chlorinated water does have a cumulative effect on the skin barrier, the eye’s mucous membranes, and hair structure. For Taiwanese swimmers training 4–6 times a week, understanding how chlorine affects the body — and adopting effective protective measures — is essential knowledge for long-term health.

The Basics of Pool Water Chemistry

The Forms Chlorine Takes in Pool Water

When chlorine is added to pool water, it reacts to form hypochlorous acid (HOCl) and hypochlorite ions (OCl⁻), collectively known as “free chlorine” — the primary disinfecting agent. Hypochlorous acid then reacts further with organic matter that swimmers bring into the pool (sweat, urine, skin secretions, etc.), forming “combined chlorine,” which includes chloramine compounds.

The truth about that smell:
Many people assume that a stronger chlorine smell means worse water quality — in fact, it’s the opposite. The strong “pool smell” comes mainly from combined chlorine (particularly trichloramine), not from free chlorine itself. A stronger odor actually indicates more organic contamination in the water and suggests water management needs improvement.

Chlorine Concentration Standards for Taiwanese Pools

According to hygiene standards set by Taiwan’s Ministry of Health and Welfare, free chlorine concentration in swimming pools should be maintained between 0.5–1.0 ppm (parts per million). At certain times, due to higher bather load or delayed re-chlorination, concentrations may run high or low — each posing different risks:

• Too high (>2 ppm): Increased irritation, redness and swelling of the eyes, worsened skin dryness
• Too low (<0.5 ppm): Insufficient disinfection, higher risk of bacterial and fungal skin infections

How Chlorine Affects Different Parts of the Body

The Mechanism of Skin Barrier Damage

The skin’s outer barrier is maintained by the “sebum film” — a natural layer of oils secreted by epidermal cells. Free chlorine is a strong oxidizer, and prolonged contact breaks down the integrity of this sebum film, accelerating moisture loss from the skin. This manifests as dryness, tightness, and flaking.

Swimmers with sensitive skin or atopic dermatitis are affected more significantly. Research points to a higher rate of impaired skin barrier function among child swimmers who train long-term in highly chlorinated pools, compared with non-swimmers.

Eye Irritation and Protection

The eye’s tear film consists of an oily layer, a watery layer, and a mucin layer, which together keep the cornea moist and healthy. Combined chlorine (particularly trichloramine) reacts with organic matter in the tear film, disrupting its stability and causing the dryness, redness, and blurred vision known as “swimmer’s red eye syndrome.”

The potential long-term impact of swimming without eye protection should not be underestimated — which is why wearing goggles is considered a basic requirement of swim hygiene.

Damage to Hair Structure

The hair’s outer layer (the cuticle) opens up in alkaline conditions, allowing chlorine compounds to more easily penetrate the hair’s cortex, where they react with melanin and proteins. Hair that has suffered long-term chlorine damage typically shows:

• Damaged, rough-feeling cuticles
• Faded color (especially noticeable in dyed hair)
• Reduced elasticity and increased breakage
• Dry scalp and increased dandruff

Protective Strategies by Body Part

Choosing a Pool with Good Water Quality

Health departments in each Taiwanese county and city regularly conduct water quality spot checks on public pools, and results can be found on the respective health authority websites. Pools with the following characteristics tend to pose a lower risk of chlorine irritation:

• High water turnover rate: Facility staff should be able to explain how often the water is changed and re-chlorinated
• Good ventilation: Poor ventilation in indoor pools allows trichloramine to accumulate — an indoor pool with a strong odor usually has poorer air quality
• Alternative disinfection technology: Some higher-end pools use UV disinfection or saltwater chlorination systems, which can maintain disinfecting effectiveness while lowering chlorine compound concentrations
• Bather load control: Limiting the number of people using the pool at once is an effective way to reduce organic contamination

Practical Recommendations

• Never skip rinsing before and after swimming: showering beforehand reduces the organic matter you bring into the pool (and is often required by pool rules), while a thorough rinse immediately afterward is the most effective way to remove residual chlorine
• Those with dry or sensitive skin can apply a thin layer of petroleum-jelly-based skin product before swimming to create a physical barrier
• Hair care: swim-specific shampoos (such as Triswim or Paul Mitchell’s Shampoo One line) contain chlorine-chelating ingredients that effectively remove residual chlorine
• Athletes training more than 2 hours a day should consider consulting a dermatologist for a personalized skin protection plan
• Children’s skin barrier function is more fragile than adults’, so extra care should be taken with post-swim skin care

Conclusion

Pool chlorination is a necessary public health safeguard, and swimmers shouldn’t let it deter them from the pool. Understanding how chlorine works, and building a complete routine of pre-swim protection and post-swim recovery, can effectively mitigate chlorine’s cumulative effects on the body. Choosing a well-managed pool and pairing it with thorough personal protective measures is the best long-term strategy for swimmers to safeguard their health.

Related Reading

• How Chlorine Affects Skin and Eyes: A Complete Post-Swim Care Routine and Product Guide
• Chlorine Water Allergy: A Complete Guide to Swimmer’s Dermatitis and Eye Protection
• Skin and Immunity in Swimmers: The Physiological Effects of Long-Term Chlorine Exposure
• Post-Swim Skin Care: How Chlorine Affects the Skin and How to Protect It