The Institute of Sport and Recreation Management
Asthma and child swimming
ISRM statement in response to reports linking the prevalence of childhood asthma with attendance at indoor chlorinated swimming pools.
ISRM's comments are as follows:
Firstly, the report implies a direct link between asthma and the use of swimming pools by children and this is simply not the case. The research findings hypothesise that, as there is some form of interference of the respiratory epithelium caused by nitrogen trichloride, this could make the lungs potentially more vulnerable to allergens which potentially could cause asthma.
The report says that the rise in childhood asthma associated with childrens' use of swimming pools could be a significant factor in the general increase in the prevalence of asthma in all children. The rise in asthma is across all sectors and age groups of society, hence there must be some other factor at work. As children have been swimming in pools in school classes for over a hundred years, ISRM would question why only now has this resulted in an increase in asthma in children, when the quality of water in pools in the UK has improved dramatically.
The researchers say that we should consider using non-chlorine disinfectants. The simple answer to this is that many pools do use supplementary forms of treatment to enhance the disinfection process such as ozone and UV. Nevertheless, all pools must provide some form of residual disinfection in the pool water to protect bathers against the risk of cross-infection.
We are not alone in using chlorine for this purpose. Chlorine is probably the most effective disinfectant in water and this is the reason it is used throughout the world, not only in swimming pools, but also in drinking water supplies. Chlorine destroys bacteria in a fraction of a second - this is the most important protection we can provide to ensure that children and bathers generally are safe from any possible cross-infection.
The report focuses on nitrogen trichloride as being the cause of the irritant to the lungs. Pool operators are well aware of this occurrence and for many years have been improving the standards of swimming pool operation through better engineering, more effective application of chemicals, better management and a drive for higher standards, reflecting the needs of their customers.
Nitrogen trichloride is formed when chlorine combines with ammonic products derived from bathers, for example sweat, urine and skin cells. To help counteract this problem, we ask that all bathers play their part by showering thoroughly and using the toilet before swimming. Pool managers play their part by providing good, hygienic conditions in pools and minimising the interface between disinfection and pollution. The report speaks of norms of 0.5mg/l NCL3 - this level is far higher than in the vast majority of UK pools where total combined chlorine is 0.5mg/l or less, of which NCL3 makes a very small proportion.
Implicit from the research is that the pool used in this experiment had no means of mechanical ventilation to extract the contaminated air, whereas the majority of pools in the United Kingdom do have this facility.
This is the second report of this type to have been produced from the Catholic University of Louvain in Brussels, which has earned them great publicity. ISRM is committed to encouraging authoritative academic research into the health aspects of the technical operation of sport and recreation facilities, particularly in any drive to reinforce water and air quality controls in pools in order to minimise exposure to any harmful agents. ISRM and the Pool Water Treatment Advisory Group (PWTAG) have long campaigned for statutory standards in this area. Hence, we would wholeheartedly support further research to show if this hypothesis has any foundation whatsoever in linking pool use to asthma.
However, if children were to be dissuaded from taking part in healthy swimming as a result of this report, ISRM would consider such an outcome damaging, as some of the greatest health challenges for the United Kingdom at this time are childhood obesity, diabetes and other health complications resulting from the increasingly sedentary lifestyles of many children.
The conclusions of the report are for further research to test a hypothesis. This should not deter anyone, particularly children, from using UK swimming pools, which in the main are operated to exemplary standards.