C4 Statement on Asthma, Children and Indoor Swimming Pools

In research updated in 2006, a Belgian team led by Dr. Alfred Bernard has suggested that frequent exposure to chloramines in indoor swimming pools might be an important factor in the rising incidence of childhood asthma and allergic diseases in industrialized countries. The Canadian Chlorine Chemistry Council (C4) notes considerable research on this topic since 2006 and believes this area requires further investigation as the study creates more questions than it answers.

In 2008, a scientific review of 25 relevant studies (Goodman and Hays, 2008) suggested that “it is premature to draw conclusions about the causal link between swimming and asthma.”

A year earlier, supported by grants from the World Chlorine Council and the National Swimming Pool Foundation, the U.S. Research Foundation for Health and Environmental Effects (RFHEE), sponsored a workshop on childhood asthma and swimming pools. Since that time two more productive expert workshops have been held to address this issue.

The workshops are an important step toward addressing key study design issues for exploring children’s exposure to environmental chemicals in swimming pools, including potential respiratory effects related to water disinfection. Workshop participants have included experts from universities and research institutes; government agencies from Europe, the U.S. and Canada; and industry observers. In a paper published after the first meeting (Weisel, et al., 2009), participants highlighted that “important data gaps need to be filled, particularly in exposure assessment and characterization of asthma in the very young” before determining whether an association exists. These data gaps are not addressed by the Bernard et al. study. These findings are consistent with several other large, well-executed studies, which also failed to find a correlation between swimming pools and asthma.” (Font-Ribera, et al., 2009; Kohlhammer and Heinrich, 2006). Meanwhile, research continues on swimming in pools and associated human health effects, including research to help standardize swimming pool data collection for comparing studies.

Swimming is a popular choice for recreation and fitness, and adequate pool maintenance is critical to ensure swimmer health and safety. Chlorine disinfectants are added to pool water to kill germs that can make swimmers ill with diarrhea, skin infections and swimmer’s ear, for example. Chloramines form when chlorine combines with the organic materials – perspiration, urine, saliva, body oils and lotions – brought into the pool by the swimmers themselves.

According to Tom Griffiths, Director of Aquatics at Penn State University in the U.S., and President, Aquatic Safety Research Group, “A soap shower will remove excess body oils and sweat, thus greatly reducing the amount of body waste going into the pool. Some pool chemists claim that if everyone showered prior to swimming, it would reduce the chlorine demand by 50%. So perhaps you could get your swimmers to shower if you told them to shower, not because they are dirty but rather because their body oils react with chlorine to produce the smell they hate.1

Ironically, chloramine levels increase when there is not enough chlorine in the pool, but many factors contribute to chloramine formation. Sound pool management, including adequate chlorination and appropriate pH, proper personal hygiene (soap showering before swimming and frequent bathroom breaks, especially for young children), and appropriate air ventilation can significantly lower chloramine levels in indoor pools.  Indeed, a properly maintained pool should have no harsh chemical odour.

C4 believes that swimming in a properly maintained pool is beneficial in terms of health, exercise and fun for children. Advice on exercise regimes (including swimming) for asthmatic children or those with allergies should be discussed with the family doctor or pediatrician.

¹ http://www.waterandhealth.org/newsletter/cleaning_air.html