“…although chlorine kills many potential pathogens, it can also react with human wastes such as perspiration, urine, skin particles, and lotion in pool water to form chloramines and 
trihalomethanes. Chloramines may remain in the pool water or volatilize into the air, where they create the pungent smell and acutely irritating properties of air above swimming pools..”
“…an outbreak associated with a swimming pool and attributed to chloramine exposure led to cough or ocular symptoms in > 70% of pool patrons interviewed.  Chloramine levels in pool water depend on chlorine and nitrogen concentrations, pool pH, temperature, and water circulation patterns.
However, chloramine levels in the air above swimming pools are also influenced by ventilation and the pool water chemistry. Indoor pools are likely to be less well ventilated than outdoor pools, so the risks associated with chloramine exposure are likely to differ between indoor and outdoor swimming pools.
For more:Â Â http://ehp03.niehs.nih.gov/article/fetchArticle.action?articleURI=info:doi/10.1289/ehp.9555
