Occupational exposure in swimming pool facilities related to disinfection by-products (DBPs) has been an issue for the last 15 years. Trichloramine (NCl3) and trihalomethanes (THMs) are DBPs formed in swimming pool water following a reaction between organic matter containing nitrogen or organic or inorganic matter, and chlorine. Due to its volatility, trichloramine can easily evaporate into the air and cause nausea and irritation of the eyes and upper airways. Symptoms are likely to be particularly pronounced in those suffering from asthma. Chloroform is the dominant THM in swimming pool atmospheres and is classified by the International Agency for Research on Cancer (IARC) as being possibly carcinogenic to humans. There are no adverse health effects reported among swimming pool employees due to occupational exposure levels of THMs found in the air at swimming pools.

There is no OEL for trichloramine adapted in Sweden, but some reference values and recommendations based on stationary measurements at the pool side are available. In 2006, the World Health Organisation (WHO) recommended a reference value for trichloramine of 500 μg/m3. The Swedish OEL for chloroform is 10 000 μg/m3.

This thesis describes research into the occupational exposure to airborne trichloramine and THMs in eight Swedish indoor swimming pool facilities and the investigation into the prevalence of adverse health effects, manifesting primarily as ocular and respiratory symptoms.

Concentrations of trichloramine and chloroform in Swedish indoor swimming pool facilities were found to be in the same range or lower compared to previous studies in other countries. The trichloramine concentrations varied between <1 and 240 μg/m3 for the personal sampling and between <1 and 640 μg/m3 for the stationary sampling. Personal trichloramine levels in the high-exposure group were more than 60% higher compared to the corresponding stationary measurements. The exposed group had a higher frequency of self-reported ocular and nasal symptoms compared to the controls. A significant difference in the concentration of exhaled FENO over a work shift with an increase in the exposed group, indicated acute airway inflammation due to respiratory irritant agent exposure. Although a dose-response effect could not be established, the results indicate an elevated risk of occupational health problems in indoor swimming pools and calls for an OEL to be established, based on personal sampling.