Is sodium hypochloride (in our local swimming pool) a trigger for an asthma attack?

Hello. My daughter is an asthma sufferer. I would like to know if sodium hypochloride which they use in our local swimming pool is a trigger for an attack. History - We had 6 weeks of my daughter being ill with asthma before Christmas so we stopped the lessons she was having and re-started them a fortnight ago. Last week after her lesson she become ill with asthma. The swimming lessons are the only consistent thing in all of that time as she was not at Pre-school and has now started school which is a new environment. Would you please take the time to answer my problem as I am in a dilemna as to whether we should stop the lessons. Many thanks

Occupational Asthma, Specialist, 2/19/2009, 2/19/2009,

The sodium hypochlorite is an unlikely cause of asthma. Asthma can be caused by breathing the air inside indoor swimming pools, where the chlorine dissolved in the water reacts with urine, sweat etc and forms nitrogen trichloride (this only appliies to pools using a chlorine releasing agent for water sterilsation). If the air in the pool is not ventilated sufficiently levels can build up during the day. If asthma is caused by nitrogen trichloride there should be regular deterioration with exposure and improvement when away. Going to the pool without getting in the water should make the asthma worse. This helps separate asthma caused by exercise, such as swiming, from that due to the pool air. Swimming Pool Asthma

2/19/2009