The December Journal of Environmental Health Perspectives reports that children who spend a lot of time around indoor pools may breathe excessive amounts of compounds that contribute to asthma. The study, led by Birgitta Json Lagerkvist from Umea University in Sweden, was conducted on 57 children ages ten and eleven. The children were given a blood test, exposed to 'ambient ozone', similar to what they might breathe at an indoor pool for two hours, then their blood was tested a second time to determine how much extra ozone was present in their system.

The elevated ozone levels detected in the children's bloodstreams by the researchers was enough to raise the concern that children repeatedly exposed to the fumes of indoor pools would suffer damage to Pulmonary Epithelial Cells, lung cells whose proper function is necessary to prevent airway restriction such as that which occurs with Asthma. The researchers suggested that the relationship to asthma and damage of these cells should be investigated further.