RECOMMENDATIONS AND UNMET NEEDS
The expansion of indoor aquatic activities resulted in a major focus of public authorities and local legislators on the prevention of water-borne infectious diseases, through the implementation and inspection of water disinfection practices. Comparatively, much less attention has been dedicated from health authorities to the indoor air quality (IAQ) of aquatic facilities, and there are still unmet needs to guarantee a generally safe and healthy indoor sport environment for both recreational and professional swimmers, and to those involved in their instruction, training, safety vigilance and pool maintenance.
There is still very limited information regarding additional hazardous pollutants, such as volatile organic compounds (VOCs) other than CBPs and ultrafine particulate matter (UFPs), and their possible long-term and cumulative health effects on swimming-pool attendants103. No guidelines are defined for UFP or THM, except for occupational chloroform exposure.
Due to the presence of both indoor THM and non-THM VOC, effective ventilation and acclimatization systems are a particular need for indoor swimming facilities to prevent the accumulation and promote the effective elimination of these harmful chlorine-derived volatile compounds.
Among the available options for water disinfection, other than chlorine-derived solutions should be considered in the planning and development of new public indoor swimming-pools. For existing facilities, avoiding any factors that promote the development, introduction and retention of air pollutants, i.e. controlling pollutant sources and ventilation levels, constitute the major action plans proposed for IAQ improvements of swimming-pools103.
Proper maintenance schedules and ventilation conditions are needed to guarantee a stable indoor environment – temperature and relative humidity - in the areas of water activities. Water-related factors – air/water temperature ratio and pH, the number of swimmers within the pool – also explain variations of the VOC levels found in the water-surface air, the air zone that is regularly inhaled by swimmers. Thus, maintaining water pH between 6.9 and 8.0 and air temperature 2 °C above the pool water are recommended to avoid level fluctuations and the undesired volatilization of CBP, particularly during periods of high attendance103. Recommendations concerning prophylactic procedures during occupational exposure are lacking but given the fluctuations of indoor pollutants concentrations found throughout a working day103, it is advisable that pool maintenance staff minimize occupational exposure by carrying in the early morning activities that require a prolonged stay in the swimming-pool surrounding area.
Checking declared indoor sources of VOC emissions, and the heating, ventilation and air conditioning (HVAC) systems (particulate matter filtration capacity and efficient removal of indoor pollutants), should also be considered104, as well as the HVAC system design, in order to guarantee that fresh air supply and exhaust airflows do not mix by proximity.
Findings suggest that early and chronic exposure to swimming-pool CBP may have a promoting effect not only on airway inflammation and hyperreactivity, but also on the process of allergic sensitization itself. Other health outcomes, namely male fertility and bladder cancer, are of particular concern, as the majority of published studies evaluate these risks in relation to drinking water and not swimming-pools exposure. Early age exposure (baby and pre-school swimming) may turn to be a relevant personal risk factor for respiratory and reproductive health effects of BP exposure in swimming pools, given the progressive increase in maturation of respiratory tract and reproductive system.
There is still need of more environmental and epidemiological research data, to ascertain the health risk associated with the exposure of different swimming pool users, namely babies, infants and children, lifeguards and swimming pool maintenance staff, coaches and elite swimmers. Additional prospective and intervention studies are also needed to confirm the relationship between exposure to pollutants in swimming-pool environments and the risk of certain health effects.