Water and air quality of eight seawater swimming pools using chlorine disinfection was measured during four sampling campaigns, spread on one full-year, and in four thalassotherapy centers located in Southeast of France. Concentrations of trihalomethanes(THMs) in air and in water as well as concentrations of parameters, including nonpurgeable organic carbon(NPOC), free residual chlorine(Cl_f), pH, Kjeldhal Nitrogen(KN), salinity,conductivity, bromide ions and, water and air temperature, were measured. Water and air samples were collected in triplicates morning — at the opening of the pools —, noon and night — at the closing of the pools —, in summer and winter. Data analysis was performed by Principal Component Analysis(PCA) and rotated component matrix, from both data quality and other parameters such as TOC, aromaticity(UV_(254)), pH, hygrometry, and free residual chlorine(Cl_f). This statistical analysis demonstrates a high correlation between TOC, Cl_fand UV_(254) and THM levels found in air and water, particularly for the major ones(CHBr_3in water:300.0 μg/L mean, 1029.0 μg/L maximum; CHBr_3 in air: 266.1 μg/m~3 mean,1600.0 μg/m~3 maximum, and CHClBr_2 in water: 18.9 μg/L mean, 81.0 μg/L maximum;CHClBr_2 in air: 13.6 μg/m~3 mean, 150.0 μg/m~3maximum). These high levels of bromoform(CHBr_3) are particularly worrisome in such health institutions, even these levels do not exceed the Permissible Exposure Limit(PEL) of 5 mg/m~3 as an 8 hour time-weighted average currently fixed by various administrations, such as Occupational Safety and Health Administration(OSHA). Water and air quality of eight seawater swimming pools using chlorine disinfection was measured during four sampling campaigns, spread on one full-year, and in four thalassotherapy centers located in Southeast of France. Concentrations of trihalomethanes (THMs) in air and in water as well as concentrations of parameters, including nonpurgeable organic carbon (NPOC), free residual chlorine (Cl_f), pH, Kjeldhal Nitrogen (KN), salinity, conductivity, bromide ions and, water and air temperature, were measured. in triplicates morning - at the opening of the pools -, noon and night - at the closing of the pools -, in summer and winter. Data analysis was performed by Principal Component Analysis (PCA) and rotated component matrix, from both data quality and Other parameters such as TOC, aromaticity (UV_ (254)), pH, hygrometry, and free residual chlorine (Cl_f). This statistical analysis demonstrates a high correlation between TOC, Cl_fand UV_ (254) Evels found in air and water, especially for the major ones (CHBr_3in water: 300.0 μg / L mean, 1029.0 μg / L maximum; CHBr_3 in air: 266.1 μg / m ~ 3 mean, 1600.0 μg / in water: 18.9 μg / L mean, 81.0 μg / L maximum; CHClBr_2 in air: 13.6 μg / m 3 mean, 150.0 μg / m 3 maximum). These high levels of bromoform (CHBr_3) , even these levels do not exceed the Permissible Exposure Limit (PEL) of 5 mg / m ~ 3 as an 8 hour time-weighted average currently fixed by various administrations, such as Occupational Safety and Health Administration (OSHA).