In humans, the threshold concentration for detection of the odor of chlorine gas ranges from 0.1–0.3 ppm. At 1–3 ppm, there is mild mucus membrane irritation that can usually be tolerated for about an hour. At 5–15 ppm, there is moderate mucus membrane irritation. At 30 ppm and beyond, there is immediate substernal chest pain, shortness of breath, and cough. At approximately 40–60 ppm, a toxic pneumonitis and/or acute pulmonary edema can develop.
Chlorine and your lungs
Chlorine gas is water-soluble and has a very low boiling point. Under moderate temperature, chlorine and chloramine (chlorine with ammonia) easily transform from a liquid to gas state.
When taking hot showers or being around large exposed bodies of chlorinated water — such as swimming pools — a small amount of chlorine evaporates into the surrounding air exposing your lungs to an elevated level of chlorine gas.
When chlorine gas is inhaled and comes into contact with the airway fluid in your lungs, it forms hypochlorous acid and hydrochloric acid, which can cause injury to the epithelial lining of the lungs.
Studies have shown those who spend a significant time around chlorinated water such as lifeguards and water park workers face an increased risk of upper respiratory tract irritation. Sometimes the effects of exposure are more severe than simple irritation.
Studies have found that “repeated exposure to chlorine in the pool has been postulated to be a significant risk factor for an excess of asthma among swimmers.” You can reduce chlorine exposure by choosing to attend swimming pools less frequently.
However, avoiding the evaporated chlorine that you inhale while taking a shower is a different story. For the latter, a high-quality water filter capable of removing chlorine is necessary.
Chlorinated water strips your body of oils that help keep your skin moisturized. Additionally, chlorine also reduces the water holding capacity of the outermost layer of skin, the stratum corneum.
For these two reasons combined, exposure to residual chlorine in bath water or swimming pools can result in dry, itchy skin and exacerbate the symptoms of certain skin diseases like eczema.
Chlorine also rids your skin of vitamin E and polyunsaturated fatty acids, resulting in worsening acne and rashes. Chlorine not only affects your skin from the outside, drinking tap water with chlorine can also affect how your skin looks and feels.
This is because chlorine is an extremely powerful oxidizing agent. Think of oxidation as what causes rust. When oxidizing agents are introduced to the body, cells go through oxidative stress. Oxidative stress is caused when molecules called free radicals damage cell structures and, ultimately, contribute to premature aging.
You can counteract these damaging effects by consuming foods or herbs high in anti-oxidants which neutralize free radicals. Another way you could fight the effects of residual chlorine is to apply moisturizer after taking a shower and by using soaps with ingredients specially formulated to neutralize chlorine.
However, these types of soaps and moisturizers can be pricey and do not fully ameliorate the effects of chlorine. The only way to effectively protect your skin from chlorine is to eliminate it from the water you use.
After spending some time swimming in chlorinated water, most people will notice their eyes are red and irritated — the reason for this is a bit more complicated than you think.
When your eyes are exposed to chlorinated water, the corneal epithelial barrier that acts like a protective shield for your cornea is eroded away leaving your eyes unprotected against bacteria and germs in the pool.
In this state, your eyes are much more susceptible to infection which is the primary cause of redness and irritation. The problem is compounded further by disinfection byproducts (DBP) created when chlorine mixes with organic compounds in the pool water.
DBPs are strong irritants and are thought to be a reason why eyes and skin get itchy after spending a long time in the pool. The most obviously way to protect your eyes is to always wear goggles whenever you are swimming.
But wearing goggles when you wash your face in the morning or take a shower is impractical and just plain silly! It would be much more convenient to just remove chlorine from your water so that it is no longer an issue.