Does Chlorine in Drinking Water Cause Asthma?

The causes of asthma are complicated. A combination of allergies to things like chlorine, structural differences in the lungs and upper respiratory system, chronic inflammation and coexisting conditions may be involved. Genetics may also play a role.

• Risk Factors

Numerous risk factors have been identified as causing an increased risk of becoming asthmatic. For example, exposure to cigarette smoke during infancy and childhood can cause "asthma-like" symptoms. If exposure ends, the symptoms typically resolve and the risk of developing severe asthma problems is reduced.

Poor air quality of any kind increases the risk, particularly during childhood. Children who live in heavily polluted environments are more likely to have symptoms. The condition is more common in urban than in rural communities due to vehicular traffic or other issues.

• Another Issue for City Dwellers

Another factor that may explain why the condition is more common in cities is the use of chlorine or chloramines to disinfect public drinking water. In areas with large populations, there are more bacteria in the water. Because of that, more disinfectants must be used to prevent outbreaks of waterborne illnesses.

• Respiratory Irritation

Chlorine, chloramines and other chemical disinfectants are respiratory irritants. Chlorine gas is toxic. It can quickly cause lung damage. Continuous exposure to the fumes may be accompanied by an increased risk of asthma during childhood and adulthood.

• Asthma Trigger

The gas is also known to trigger the asthmatic response. In other words, brief exposure to the fumes, even at low concentrations, can cause wheezing, coughing and other symptoms. Bleach and other cleaning products cause a similar response. When you use chlorinated water and cleansers that contain bleach, you further increase your risk of attack. While a person's first thought may be that keeping the house cleaner will reduce the risk of attacks, the opposite may actually be true.

• How Chlorine Causes Lung Irritation

Chlorine reacts with moisture in the lungs to form hydrochloric acid, another irritant that can be lethal. The gas was one of the first chemical weapons. It was used in World War I by German forces. The concentration found in the air of a home due to chlorinated tap water is not high enough to cause death from hydrochloric acid, but it can and does cause asthma problems and irritates other respiratory ailments.

• Another Problem

• Chlorination leads to the production of disinfection byproducts like trihalomethanes (THMs). Exposure to THMs increases a person's lifetime risk for several kinds of cancer. The more exposure, the greater the risk. For example, a person who swims frequently in chlorinated water, showers in chlorinated water and drinks chlorinated tap water is said to have an "unacceptable" risk.

• What to Do

Swimmers don't want to stop swimming. Public treatment facilities cannot stop disinfecting tap water. People cannot stop showering. Drinking bottled water does not necessarily address the issue. Some bottle water brands contain chlorine.

The best way to reduce your exposure to chlorine is to keep it out of your home. In my next article you will learn how removing chlorine from tap water may help asthma. You'll also learn how to accomplish that feat. It's not really that difficult.