Swimming pool hazards

I draw attention to a misinterpretation in the article "Asthma and swimming pools" (June 9), where it is stated that:

"Recent articles in respectable medical journals show that the highly volatile nitrogen chloride, which is generated when chlorine interacts with organic matter (skin, sweat, urine etc), affects the lining of the bronchial tree.

"These researchers could demonstrate lung damage in schoolchildren after using indoor swimming pools regularly at weekly intervals."

Nitrogen trichloride is, in fact, the chlorinating agent used in swimming pools to ensure they are hygienic. It is volatile substances known as chloramines which are formed by the reaction of this substance in the water with nitrogen-containing compounds found in sweat and urine.

All bathers should be encouraged to use the toilet and showering facilities prior to swimming to ensure that the water is kept as free as possible from body pollutants - which are the problem.