EDITORIAL Indoor swimming pools, water chlorination and respiratory health

Swimming is generally considered to be a healthy leisure activity for both the young and old. Swimming is even often advised as the most appropriate sport for asthmatic children [1–3], mainly (but probably not solely) on the grounds that inhaling moist air is less conducive to triggering exercise-induced asthma [4]. However, for obvious reasons of microbiological safety, the water of public and private swimming pools must be disinfected [5]. The most common pro-cedure for water disinfection consists of chlorination. As with all human and technological intervention, the use of chlorine-based products to disinfect swim-ming water may lead to a number of unwanted effects, in particular the presence of chlorine-containing compounds in the air. Consequently, chlorinatio