Indoor swimming pools linked to childhood asthma

physorg.com:

"Investigators in Belgium analysed data from 190,000 youngsters aged 13-14 in 21 countries, who were asked to give details about any breathing problems, hay fever and atopic eczema.

The researchers found a preponderance of asthma and wheezing in towns and cities where there was a high density of indoor pools.

Rates of asthma and wheeze rose by 2.73 and 3.39 percent respectively for every additional indoor swimming pool. Prevalence of these problems was higher in Western Europe than in Eastern Europe, mirroring the higher number of pools in the western part of the continent.

The study appears online in Occupational and Environmental Medicine, published by the British Medical Association (BMA).

Chief author Alfred Bernard, a professor of public health at the Catholic University of Louvain, Brussels, believes the cause lies with nitrogen trichloride, a gassy, easily inhalable irritant.

This chemical, also called trichloramine, is released when chlorinated water reacts with urine, sweat or other organic matter brought by swimmers.

Bernard notes that more and more swimming pools have been built in past decades and, thanks to their increasingly lavish equipment, such as wave machines and slides, children spend more and more time there. "