Abstract
—The main objective of this work is to summarize the most commonly used dielectric fluids in the power distribution transformers, as well as to discuss what are the latest and the rationale behind those trends. The favorable and unfavorable reasons for any choice behind each of those dielectric fluids will be discussed. Additionally, this work also advances the power distribution transformers health index most commonly used to assess the condition of the transformer.

Abstract
Recently, indoor swimming pool activities have increased to promote health-enhancing physical activities, which require establishing suitable protocols for disinfection and water quality control. Normally, the assessment of the microbial quality of the water in the pools only considers the presence of different bacteria. However, other less frequent but more resistant pathogens, such as free-living amoebas (FLA), are not contemplated in both existing recommendation and research activities. FLA represent a relevant human health risk, not only due to their pathogenicity but also due to the ability to act as vehicles of other pathogens, such as bacteria. Therefore, this work aimed to study the physicochemical characteristics and the occurrence of potentially pathogenic FLA and bacteria in water samples from 20 public indoor swimming facilities in Northern Portugal. Our results showed that some swimming pools presented levels of pH, free chlorine, and conductivity out of the recommended limits. Pathogenic FLA species were detected in two of the facilities under study, where we also report the presence of both, FLA and pathogenic bacteria. Our findings evidence the need to assess the occurrence of FLA and their existence in the same environmental niche as pathogenic bacteria in swimming pool facilities worldwide and to establish recommendations to safeguard the health of the users.

Abstract
While it is generally accepted that our fossil fuel-dominated energy systems must undergo a sustainable transition, researchers have often neglected the potential impacts of this on water and land systems. However, if unintended environmental impacts from this process are to be avoided, understanding its implications for land use and water demand is of crucial importance. Moreover, developed countries may induce environmental stress beyond their own borders, for instance through extensive imports of bioenergy. In this paper, Germany serves as an example of a developed country with ambitious energy transformation targets. Results show that in particular, the politically-driven aspiration for more organic farming in Germany results in a higher import quota of biomass, especially biofuels. These imports translate into land demand, which will exceed the area available in Germany for bioenergy by a factor of 3-6.5 by 2050. As this will likely bring about land stress in the respective exporting countries, this effect of the German energy transformation ought to be limited as much as possible. In contrast, domestic water demand for the German energy system is expected to decrease by over 80% through 2050 due to declining numbers of fossil-fuelled power plants. However, possible future irrigation needs for bioenergy may reduce or even counterbalance this decreasing effect. In addition, energy policy targets specific to the transport sector show a high sensitivity to biomass imports. In particular, the sector-specific target for greenhouse gas reductions will seemingly promote biomass imports, leading to the above-described challenges in the pursuit of sustainability.

Abstract
This is the study of the thermal efficiency performance of a possible 1-ha solar pond located at Caota beach, in Benguela, Angola. During the first year of operation there was no energy extraction from the pond and the water temperature in the lowest and denser layer reached 93 degrees C. From the second year onwards thermal energy was extracted. Two scenarios were adopted, water heating from 40 to 60 degrees C or water heating from 50 to 70 degrees C. Yearly 1600 MWh and 700 MWh could be extracted, in the first and or the second scenario. Operating regimes of 8, 12 or 24 h/day were considered. Based on the total pond incident solar energy, the overall energy efficiency of the pond is in the 2 to 5 % range, while the exergy efficiency is in the 0.4 to 2.6 % range. The repartition of the pond energy losses is also quantified.

Abstract
Exposure to air pollution in early years can exacerbate the risk of noncommunicable diseases throughout childhood and the entire life course. This study aimed to assess temperature, relative humidity (RH), carbon dioxide (CO2) and monoxide (CO), particulate matter (PM2.5, PM10), ultrafine particles, nitrogen dioxide (NO2), ozone (O3), formaldehyde, acetaldehyde and volatile organic compounds (VOC) levels in the two rooms where infant twins spend more time at home (30 dwellings, Northern Portugal). Findings showed that, in general, the worst indoor environmental quality (IEQ) settings were found in bedrooms. In fact, although most of the bedrooms surveyed presented adequate comfort conditions in terms of temperature and RH, several children are sleeping in a bedroom with improper ventilation and/or with a significant degree of air pollution. In particular, mean concentrations higher than recommended limits were found for CO2, PM2.5, PM10 and total VOC. Additionally, terpenes and decamethylcyclopentasiloxane were identified as main components of emissions from indoor sources. Overall, findings revealed that factors related to behaviors of the occupants, namely related to a conscientious use of cleaning products, tobacco and other consumer products (air-fresheners, incenses/candles and insecticides) and promotion of ventilation are essential for the improvement of air quality in households and for the promotion of children's health.

Abstract
Since children are far more vulnerable than adults to the effects of air pollution and spend about a third of their day in school, strict control of indoor environments in educational buildings is paramount to prop-erly identify, manage and mitigate putative environmental risks for children. In this context, this work aimed to provide a holistic view on the outcomes obtained from the national ARIA project, which was focused on broadening the knowledge on the effects on children's health of the exposure to schools' indoor air. In particular, this work performed a comprehensive investigation of the indoor air quality (IAQ) in 20 public primary schools located in Porto (Northern Region, Portugal). This paper presents the results of the investigation along with the recently published main outcomes of ARIA on (1) the char-acteristics of the environment surrounding the surveyed buildings, and (2) the school's environment-related health effects in school-age children from the studied classrooms. The investigation consisted in an extensive assessment plan conducted in 71 classrooms to assess temperature, relative humidity, carbon monoxide and dioxide, particulate matter (PM2.5, PM10, and ultrafine particles), nitrogen dioxide, ozone, volatile organic compounds, formaldehyde, acetaldehyde, airborne fungi, bacteria and endotoxins, and investigate their respective sources, during the cold seasons of 2014-2015. A series of studies was also launched to investigate school environment-related health detriments in 916 children. The results showed that comfort and ventilation issues and/or indoor pollutant levels that exceeded recommended limits were found in a substantial number of the classrooms surveyed. The high density of occupants, deficient ventilation, soil characteristics, presence of indoor pollution sources (e.g. classroom materials and consumer products) and outdoor pollution were some of the factors that seemed to explain the high air stuffiness and/or indoor pollution load identified in classrooms. In fact, some of indoor pollutants detected, even at low exposure levels, were associated with the development of respiratory symptoms in school-age children. Moreover, results from this work have also shown that the characteristics of the environment surrounding the schools, namely the presence of green spaces and species richness, can be major determinants of respiratory health among school-age children. Overall, the body of evidence generated from the ARIA project can support new evidence-based perspectives for promotion of health in educational buildings.