From Swimming Pool News, March 2010:
The case for using lower levels of chlorine in swimming pools has been boosted with a new research paper from Denmark.
The paper, which is expected to be available at the Swimming Pool & Spa International Conference in London in March, shows it is possible to achieve significant improvements in the water quality and improved indoor air quality in pools by using a lower content of free chlorine than are currently used in swimming pools. The trial was carried out at the Gladsaxe Sports centre in Denmark.
The trial was carried out by the DHI Group (Danish Hydraulic Institue/ Water Quality Institute), and funded jointly by the Danish Association for Swimming Pool Technology and the Danish Environmental Protection Agency.