from the web... google cholramines and sunlight
Monochloramine hydrolyses slowly in aqueous solutions.Aeration and boiling of water are not effective for the removal of monochloramine; a minimal aeration loss of 10–15% has been reported with monochloramine.Ultraviolet light depletes only free chlorine, whereas chloramines seem to be quite stable in sunlight. Chloramine decay has been suggested to be at most 0.2 mg/L per sunlight hour between 10 a.m. and 2 p.m. (latitude 30–40°N).
Monochloramine hydrolyses slowly in aqueous solutions.Aeration and boiling of water are not effective for the removal of monochloramine; a minimal aeration loss of 10–15% has been reported with monochloramine.Ultraviolet light depletes only free chlorine, whereas chloramines seem to be quite stable in sunlight. Chloramine decay has been suggested to be at most 0.2 mg/L per sunlight hour between 10 a.m. and 2 p.m. (latitude 30–40°N).