Assessment of the air quality in 20 public indoor swimming pools located in the Northern Region of Portugal.

Air exposures occurring in indoor swimming pools are an important public health issue due to their popularity and regular use by the general population, including vulnerable groups such as children and elderly people. More comprehensive information on indoor air quality (IAQ) in swimming pools is thus needed in order to understand health risks, establish appropriate protective limits and provide evidence-based opportunities for improvement of IAQ in these facilities. In this context, twenty public indoor swimming pools located in the Northern Region of Portugal were examined in two sampling campaigns: January-March and May-July 2018. For each campaign, a comprehensive set of environmental parameters was monitored during the entire period of the facilities' operating hours of a weekday, both indoors and outdoors. In addition, four air (1-h samplings) and water samples were collected. Findings show that comfort conditions, ultrafine particles number concentrations and exposure to substances in the indoor air (concentration and composition) is likely to vary greatly from one public indoor swimming pool to another. Trihalomethanes (THM) and dichloroacetonitrile were the predominant disinfection by-products identified in the indoor air but other potentially hazardous volatile organic compounds, such as limonene, 1,2,4-trimethylbenzene, 2,2,4,4,6,8,8-heptamethylnonane, 2- and 3-methylbutanenitrile, acetophenone, benzonitrile, and isobutyronitrile were found to have relevant putative emission sources in the environment of the swimming pools analyzed. Furthermore, indicators of poor ventilation conditions (namely carbon dioxide, relative humidity and existence of signs of condensation in windows) and some water-related parameters (THM levels, conductivity and salinity) were found to be determining factors of the measured airborne THM concentrations that appeared to significantly potentiate the exposure. In summary, this work provides evidence for the need to establish adequate standards for the comprehensive evaluation of IAQ in public swimming pools, in order to guide further development of evidence-based prevention/remediation strategies for promoting healthy environments in swimming pools.

New designs for MRI contrast agents.

New designs for Magnetic Resonance Imaging contrast agents are presented. Essentially, they all are host-guest inclusion complexes between y-cyclodextrins and polyazamacrocycles of gadolinium (III) ion. Substitutions have been made to the host to optimise the host-guest association. Molecular mechanics calculations have been performed, using the UFF force field for metals, to decide on the suitability of the substitutions, and to evaluate the host-guest energies of association. Interesting general conclusions have been obtained, concerning the improvement of Magnetic Resonance Imaging contrast agents; namely, a set of rational methodologies have been deduced to improve the association between the gadolinium (III) chelates and the cyclodextrins, and their efficiency is demonstrated with a large set of substituted complexes, opening new doors to increase the diagnostic capabilities of Magnetic Resonance Imaging.