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Worldwide, buildings have been presented as one of the main energy consumers and, for that matter, there is an increased tendency to invest in policies and measures that promote more efficient buildings. Among the chosen strategies, the need to promote the use of passive solutions and retrofit the existing building stock is often pointed out. Portuguese building stock has proven to be obsolete in terms of thermal comfort, which can directly affect the energy demand for climatization purposes. Considering the great solar availability in the country, when compared to other European locations, building retrofit with solar passive technologies can be a suitable solution. This paper aims to review studies on the application of solar passive technologies to retrofit façades in the Mediterranean climate context, with a special focus on Portugal. Four retrofit passive solar technologies were reviewed, namely glazing, sun shading, sunspaces and Trombe wall technologies.

This paper addresses the impacts introduced on Distribution Transformer (DT) aging due to the integration of nearly Zero-Energy Buildings (nZEBs) into existing Low-Voltage Distribution Grids. The study considers a neighborhood in the Portuguese municipality of Evora where buildings are set to become nZEBs using solar Photovoltaic systems. This transition is reproduced by simulation using real pre-transition electricity demand and climate data. Following the IEC 60076-7 standard to model the aging process of the considered DT, the collected results show that nZEBs can have a positive impact on the analyzed aging process. However, when relatively high nZEB integration levels are considered, this study also reveals that the subsequent reverse power flows can achieve relatively large magnitudes, especially around noon, thus accelerating the DT's aging into prohibitive values. Given the utmost importance of the nZEB concept for the European building stock, this study identifies nZEBs operation related issues that can result from excessive coincident on-site generation and presents a battery based power export limitation strategy to mitigate such impacts on DT aging.

The structural components of load-bearing concrete frame buildings, such as concrete beams and columns, are critical elements of the facades which often act as a thermal bridge. To reduce the impact of structural thermal bridge areas in non-retrofitted Portuguese residential buildings, a new innovative solar passive retrofit solution, named Solar Bridge Retrofit System (SBRS), is proposed. This concept relies on the principles of unvented Trombe wall systems and consists in using an external transparent skin in front of the structural areas of the envelope in combination with the traditional ETICS in the remaining area. Contrary to the traditional Trombe walls, this innovative design enables the heavy structure of the building to absorb solar radiation and conduct the heat slowly inward or to the adjacent structure. To evaluate the thermal performance of the SBRS, an experimental setup was developed. The field results obtained during February and March 2020 for two different configurations, showed that the double-glazing configuration in combination with ETICS has the potential to improve thermal comfort and reduce energy consumption. This paper addresses both the design of the SBRS and the obtained results from the experimental work.

The work reported here addresses load matching improvement in Net Zero Energy Buildings (Net-ZEBs). The related relevant literature shows that currently research work is mainly focused on improving the load matching of individual buildings. In this paper the concept of a Cooperative Net Zero Energy Community (CNet-ZEC) is introduced, extending discussion to the enhancement of load matching at a wider community level. Both building and community levels are compared in order to assess the work proposed here, through the analysis of three distinct scenarios where five Net-ZEBs work individually or in community. The results presented here were obtained through a detailed simulation based on 1-min resolution stochastic load profiles and recorded weather data. The results indicate that over the period of a year the CNet-ZEC has the potential to increase the electrical demand covered by onsite electricity generation up to 21% and the on-site generation that is used by the building up to 15%. The following elements are considered by the CNet-ZEC in order to produce those results: (i) demand heterogeneity of the buildings integrating the community; (ii) the higher number of controllable devices; and (iii) the potential higher amount of energy available to satisfy the community demand.

Adaptive building envelopes can provide improvements in the building energy efficiency and economics, through their capability to change their behaviour in real time according to indoor-outdoor parameters, by means of materials, components and systems. Therefore, adaptive facades can make a significant and viable contribution to meeting the EU's 2020 targets. Several different types of adaptive facade concepts have already been developed, and an increase in emerging, innovative solutions is expected for the near future. The objective of this paper is to contribute to these developments by presenting the findings of an analysis of the existing concepts and case studies and by proposing a new approach for characterization of these elements.

This study assesses the potential of energy flexibility of space heating and cooling for a typical household under different geographical conditions in Portugal. The proposed approach modifies the demand through the optimization of the thermostat settings using a genetic algorithm to reduce either operational costs or interaction with the grid. The results show that the used energy flexibility indicator expresses the available potential and that flexibility depends on several factors, namely: i) thermal inertia of the archetypical household; ii) the time of use electricity tariffs; iii) users’ comfort boundaries; and iv) the geographical location of the houses.

Building Integrated Photovoltaics (BIPV) are becoming an attractive solution in the context of high penetration of photovoltaics (PV) in buildings caused by the strive to achieve net or nearly zero energy status. Besides retrieving solar radiation to produce electricity, BIPV also offers aesthetical advantages because of its architectural feature. This paper reports on the electrical energy performance of a passive solar office building, Solar XXI, located in Lisbon, Portugal, which has installed on the South façade a BIPV (12 kWp) and an additional photovoltaic roof system in a nearby car park facility (12 kWp) for electricity generation. The main objective is to investigate the potential to increase load matching between energy generation and consumption and improve grid interaction for two scenarios using the energy flexibility enabled by the integration of Battery Energy Storage Systems (BESS) with capacities ranging from 13.5 kWh to 54 kWh. To collect the required results, real consumption and generation data are used, together with numerical simulations related to the integration of the BESS. The results show that load matching and grid interaction related metrics can be significantly improved by using the energy flexibility provided by a BESS and that the implementation of such system can be economically viable for a 10-year period. info:eu-repo/semantics/publishedVersion

Controlling the air quality is of the utmost importance in today&rsquo, s buildings. Vertical air curtains are often used to separate two different climatic zones with a view to reduce heat transfer. In fact, this research work proposes an air curtain aimed to ensure a proper separation between two zones, a clean one and a contaminated one. The methodology of this research includes: (i) small-scale tests on water models to ensure that the contamination does not pass through the air curtain, and (ii) an analytical development integrating the main physical characteristics of plane jets. In the solution developed, the airflow is extracted from the contaminated compartment to reduce the curtain airflow rejected to the exterior of the compartment. In this research work, it was possible to determine the minimum exhaust flow necessary to ensure the aerodynamic sealing of the air curtain. This article addresses the methodology used to perform the small-scale water tests and the corresponding results.

As demand response and energy flexibility are often suggested as key principles to facilitate high levels of renewable energy sources into energy markets, different studies evaluated the potential impact of energy flexibility in buildings. Nonetheless, due to differences in definition and quantification methodologies for energy flexibility, comparing results between such studies is difficult. With a review and applied evaluation of existing definitions and quantification methodologies this paper aims at assessing the applicability, benefits and drawbacks of each quantification methodology. The conducted review shows that energy flexibility definitions found in the literature have their particularities despite sharing the same principle that energy flexibility is the ability to adapt the energy profile without jeopardizing technical and comfort constraints. The survey of quantification methodologies reveals two main approaches to quantify energy flexibility. A first approach quantifies energy flexibility indirectly using past data and assuming a specific energy system and/or energy market context. The second approach directly predicts the energy flexibility that a building can offer to the energy system in a bottom-up manner. While applications for both approaches were identified, this paper focuses on the latter. By applying methodologies that follow this second approach to a common case study, three common properties of energy flexibility were observed: i) the temporal flexibility; ii) the amplitude of power modulation; iii) and the associated cost.

With the publication of the new Energy Performance of Buildings Directive, a large number of buildings are expected to become high energy performance and explore more the availability of renewable energy resources. Such buildings are often described in literature as nearly Zero-Energy Buildings (nZEB). Because renewable energy sources, such as wind and solar power, have an intrinsic variability, the zero-energy annual balance of nZEBs is difficult to reach at short time resolution (e.g. hourly). Thus, since electricity generation from small-scale solar renewable (typical case in Portugal) in individual households has limited capacity to be adjusted according to the power system needs, it is relevant to consider the demand flexibility potential, specially at community level (cluster of buildings). Unfortunately, there is a lack of studies on the impact of changes in electricity use at urban level on the future energy systems. Therefore, an approach addressing the energy flexibility (EF) in buildings may allow obtaining useful exploratory directions for the construction sector and related markets, policy makers and regulatory bodies. For these reasons, an exploratory project aimed at examining the potential of EF at the level of an existent neighbourhood in Lisbon was initiated. In this article we describe the objectives, design, and methods of the FIRST project, designed to map out the potential for EF in terms of benefits and costs in Lisbon.

This study addresses the energetic performance of an attached-sunspace applied to an existing residential building in Portugal. Four configurations (two attached, one integrated and one partially integrated) are studied in six different climatic zones. In addition other key parameters are considered such as ventilation (with or without natural ventilation), shading devices (one external and two internal configurations), number of glazed surface layers (single glazed and double glazed) and orientation (South, East and West). The thermal performance analysis, carried out using a dynamic simulation code, proved that energy savings for retrofitting design can be very important and that in climates with warm summers the risk of overheating can be considerably diminished through an accurate analysis based on modeling.

The chapter summarises techniques - combined in solution sets - used in the case studied buildings to achieve buildings with net zero energy or energy neutral standard.

PurposeThis paper sets out to implement bounded high‐order (HO) resolution schemes in a hybrid finite volume/finite element method for the solution of the radiative transfer equation.Design/methodology/approachThe hybrid finite volume/finite element method had formerly been developed using the step scheme, which is only first‐order accurate, for the spatial discretization. Here, several bounded HO resolution schemes, namely the MINMOD, CLAM, MUSCL and SMART schemes, formulated using the normalized variable diagram, were implemented using the deferred correction procedure.FindingsThe results obtained reveal an interaction between spatial and angular discretization errors, and show that the HO resolution schemes yield improved accuracy over the step scheme if the angular discretization error is small.Research limitations/implicationsAlthough the HO resolution schemes reduce the spatial discretization error, they do not influence the angular discretization error. Therefore, the global error is only reduced if the angular discretization error is also small.Practical implicationsThe use of HO resolution schemes is only effective if the angular refinement yields low‐angular discretization errors. Moreover, spatial and angular refinement should be carried out simultaneously.Originality/valueThe paper extends a methodology formerly developed in computational fluid dynamics, and aimed at the improvement of the solution accuracy, to the hybrid finite volume/finite element method for the solution of the radiative transfer equation.

The main sources of moisture on building facades are rain and condensation. Being moisture a prerequisite for the development of microbial growth it is of great interest to identify and analyse the factors responsible for these wetting mechanisms. The development of the microbial vegetation, in addition of being potentially damaging to the building envelope, creates a visual nuisance. This work aims to study the external environment conditions favourable for exterior surface condensation of buildings. The risk for occurrence of surface condensation depends mainly on the surface energy balance and on the moisture content of the ambient air. Because external surface temperature of buildings are very sensitive to convective and radiative exchanges, the investigation has been conducted analysing both convective and radiative heat transfer coefficients for a wide range of scenarios covering different climate sensitivities and building envelope qualities. The analysis has shown that convection and the moisture content of the air play a key role in the occurrence of surface condensations on building facades.

It was recently created in Portugal a methodology for residential building acoustics classification. This methodology takes into account three levels of evaluation, being one of them, the dwelling. To evaluate the dwelling are considered eight descriptors which are weighted by specific coefficients in order to establish a differential influence of each descriptor in the dwelling’s final evaluation score. This paper focus on a detailed analysis on the reliability of these weighting coefficients as values that are supposed to reflect the population complains related to the various types of sounds (neighboring; external; equipment) they are exposed to, and so that on which descriptors have more or less influence in the acoustic comfort provided by the dwelling. The magnitude of these coefficients was studied and obtained through a social survey, conducted using a fill tool on-line. Based on the obtained results, it was possible to define a set of adequate values for these coefficients, and thus compare them with the ones established on the acoustic evaluation scheme for residential buildings existing in Portugal. 7pp Seminário / Forum Acusticum DED/NAICI

Children attending day care centers (CDCC) have been reported to be more prone to infectious diseases when compared with those cared for at home, and are exposed to conditions that may increase the risk of allergies and asthma. Several studies revealed that consequences of poor ventilation conditions include high levels of carbon dioxide (CO2) and many other indoor pollutants commonly detected in schools. Nine child day care centers were selected randomly to participate in this study. Fifty-two classrooms were assessed for chemical, biological, physical, and allergen parameters in spring and winter seasons in these nine CDCC located in Porto, Portugal. Outdoor measurements were also conducted for comparison. Our results indicated that (i) particulate matter (PM10) median levels were above the national reference levels, both by classroom type and by season; (ii) TVOC kindergarten peak values may raise some concern; (iii) CO2 was present at high median and maximum levels during spring and winter assessment in both nurseries and kindergartens classrooms; (iv) total bacteria concentrations were 57- and 52-fold higher in the nursery and kindergarten than outdoors, respectively, for the spring season; (v) winter and spring median predicted mean vote (PMV)indices were between “neutral” (0) and “slightly cool” (≤ –1) in the thermal sensation scale for comfort situations (−2 to 2) for both types of classrooms; (vi) there were significant differences for both PMV and predicted percentage of dissatisfied (PPD) indices by season; and vii) CO2, total bacteria, and gram-negative bacteria were associated with low airflow rates. These data will help to evaluate the effectiveness of current building operation practices in child day care centers regarding indoor air quality and respiratory health. Our research is supported by ENVIRH Project (www.envirh.fcm.unl.pt): PTDC/SAUESA/100275/2008, and a PhD grant (SFRH/ BD/72399/2010) from the Foundation for Science and Technology (Fundação para a Ciência e Tecnologia, FCT).

Poor ventilation at day care centres (DCCs) was already reported, although its effects on attending children are not clear. This study aimed to evaluate the association between wheezing in children and indoor CO2 (a ventilation surrogate marker) in DCC and to identify behaviours and building characteristics potentially related to CO2. In phase I, 45 DCCs from Lisbon and Oporto (Portugal) were selected through a proportional stratified random sampling. In phase II, 3 months later, 19 DCCs were further reassessed after cluster analysis for the greatest difference comparison. In both phases, children’s respiratory health was assessed by ISAAC-derived questionnaires. Indoor CO2 concentrations and buildingcharacteristics of the DCC were evaluated in both phases, using complementary methods. Mixed effect models were used to analyze the data. In phase I, which included 3,186 children (mean age 3.1±1.5 years), indoor CO2 concentration in the DCC rooms was associated with reported wheezing in the past 12months (27.5 %) (adjusted odds ratio (OR) for each increase of 200 ppm 1.04, 95 % CI 1:01 to 1:07). In phase II, the association in the subsample of 1,196 children seen in 19 out of the initial 45 DCCs was not significant (adjusted OR 1.02, 95 % CI 0.96 to 1.08). Indoor CO2 concentration was inversely associated with the practices of opening windows and internal doors and with higher wind velocity. A positive trend was observed between CO2 and prevalence of reported asthma (4.7 %). Conclusion: Improved ventilation is needed to achieve a healthier indoor environment in DCC. Fundação para a Ciência e Tecnologia—ENVIRH Project PTDC/SAU-ESA/100275/2008 and PEst-OE/MAT/UI0006/2014.

Modelling of ventilation is strongly dependent on the physical characteristics of the building of which precise evaluation is a complex and time consuming task. In the frame of a research project, two children day care centres (CDCC) have been selected in order to measure the envelope air permeability, the flow rate of mechanical ventilation systems and indoor and outdoor temperature. The data obtained was used as input to the computer code CONTAM for ventilation simulations. The results obtained were compared with direct measurements of ventilation flow from short term measurements with CO2 tracer gas and medium term measurements with perfluorocarbon tracer (PFT) gas decay method. After validation, in order to analyse the main parameters that affect ventilation, the model was used to predict the ventilation rates for a wide range of conditions. The purpose of this assessment was to find the best practices to improve natural ventilation. A simple analytical method to predict the ventilation flow rate of rooms is also presented. The method is based on the estimation of wind effect on the room through the evaluation of an average factor ( ) ¥ 2 ΔP / ρ * and on the assessment of relevant cross section of gaps and openings combined in series or in parallel. It is shown that it may be applied with acceptable accuracy for this type of buildings when ventilation is due essentially to wind action. This research was undertaken as part of a research project supported by the Fundação para a Ciência e Tecnologia under Grant PTDC/SAU-ESA/100275/2008 (ENVIRH).

International audience; The International Energy Agency (IEA), through the Solar Heating and Cooling programme (SHC) Task 40 and the Energy Conservation in Buildings and Community Systems programme (ECBCS, now named EBC) Annex 52, works towards developing a common understanding and setting up the basis for an international definition framework for Net Zero Energy Buildings (Net ZEBs). One of the subtasks of this programme –SubTaskC focuses benchmarking the Net ZEBs around the world to identify the innovative solutions sets that makes up this new type of building. This paper presents an overview of the work conducted by the participants of Subtask C and of Zero Energy Building projects that have been identified.

Net zero-energy buildings (Net ZEBs) have been the object of various studies in recent years as various countries have set this performance as long-term goal of their energy policies. Designing successful Net ZEBs represents a challenge since the definitions are yet generic, the assessment method and monitoring approach are under development and the literature is relatively scarce about the best sets of solutions for different typologies and climates likely to deliver an actual and reliable performance in terms of energy balance (used consumed vs. generated) on a costeffective basis. The International collaborative research initiative between the Solar Heating and Cooling (SHC) and the Energy Conservation in Buildings and Community Systems (ECBCS) through Task 40/Annex 52 - Towards Net-Zero Energy Solar Buildings-, summarises most of the recent developments in this field. The authors of this article, who are participants in this task, are providing insights from on-going research work on some best practice leading projects which have been the object of an exploratory cross-case analysis in order to facilitate identification of the set of relevant design strategies. The close inspection of the strategies and indicators of the relative performance of the projects revealed interesting features about the combination of design challenges with techniques and technologies responsible for delivering the Zero Energy performance.

There are many different possible combinations of building envelope, utility equipments and onsite energy generation equipments that can lead to net zero-energy performance. For instance, a building with standard design can offset its energy demand by adding a large amount of photovoltaic cells or by improving its energy efficiency rating first and then adding a smaller amount of photovoltaic cells. Despite the second strategy being considered the roadmap to net zeroenergy status, the first scenario is also possible in the actual Portuguese context where laws favor conditions for the installation of PV s and solar thermal systems. This paper intends to discuss the implications of this fact from a national perspective coupled with the IEA SHC Task 40 ECBCS Annex 52 vision where authors are active participants.

Zero-energy performance buildings have gained significant attention since the publication in 2010 of the recast of the EPBD recast which requires all new buildings to become nearly zero-energy by 2020. Buildings are requested to meet higher levels of energy performance and to explore more the alternative energy supply systems available locally on a cost-efficiency basis. Since the directive does not specify minimum or maximum harmonized requirements as well as details of energy performance calculation framework, it is up to the member states to define the exact meaning of “high energy performance” and “amount of energy from renewable sources” according to their own local conditions and strategic interests. Nearly zero-energy building (nZEB) performance derives from net zero-energy concept (Net ZEB) which in case of buildings is usually defined as a high energy performance building that over a year is energy neutral. The successful implementation of such an ambitious target, however, needs to be planned out diligently. The critical steps are a) a correct picture about the existing state and trends, b) clear definitions and targets, c) dynamic building codes and energy efficient technologies and d) rules for testing and verification. The nZEBs or NetZEBs built in the near future therefore may play a critical role in implementing any ambitious plan as its success on long-term relies on setting best practice examples, in addition of the supporting policies and initiatives. The purpose of this paper is to review existing definitions, terms and policies on strategic planning of nZEBs at national and international level.

Net Zero-Energy Buildings (NZEBs) have received increased attention in recent years as a result of constant concerns about energy supply constraints, decreasing energy resources, increasing energy costs and the rising impact of greenhouse gases on world climate. Promoting whole building strategies that employ passive measures together with energy efficient systems and technologies using renewable energy became a European political strategy following the publication of the Energy Performance of Buildings Directive recast in May 2010 by the European Parliament and Council. However designing successful NZEBs represents a challenge because the definitions are somewhat generic while assessment methods and monitoring approaches remain under development and the literature is relatively scarce about the best sets of solutions for different typologies and climates likely to deliver an actual and reliable performance in terms of energy balance (consumed vs generated) on a cost-effective basis. Additionally the lessons learned from existing NZEB examples are relatively scarce. The authors of this paper, who are participants in the IEA SHC Task 40-ECBCS Annex 52, “Towards Net Zero Energy Solar Buildings”, are willing to share insights from on-going research work on some best practice leading NZEB residential buildings. Although there is no standard approach for designing a Net Zero-Energy Building (there are many different possible combinations of passive and efficient active measures, utility equipment and on-site energy generation technologies able to achieve the net-zero energy performance), a close examination of the chosen strategies and the relative performance indicators of the selected case studies reveal that it is possible to achieve zero-energy performance using well known strategies adjusted so as to balance climate driven-demand for space heating/cooling, lighting, ventilation and other energy uses with climate-driven supply from renewable energy resources.

É do conhecimento geral que a qualidade do ar interior influencia a qualidade de vida dos ocupantes dos edifícios e que pode ter implicações significativas no seu estado de saúde. As pessoas idosas constituem um grupo mais vulnerável que pode ser afectado quando exposto a um ambiente interior de menor qualidade. O projecto GERIA reúne uma equipa multidisciplinar que tem como objectivo principal estudar as possíveis associações entre as condições de ventilação existentes em estruturas residenciais para pessoas idosas (ERPI), a qualidade do ar interior (QAI) e a prevalência de doenças do foro respiratório nos residentes. Para alcançar este objectivo o projecto foi es-sencialmente desenvolvido em duas fases. Para avaliar as características construtivas e a saúde e a qualidade de vida dos residentes, na fase I, foi realizado um estudo preliminar em 21 ERPI no Porto e 33 em Lisboa recorrendo a inspecções visuais e questionários. Na fase II, a partir dos 54 considerados na fase I, foram seleccionados através duma análise de clus-ters um número de 4 ERPI no Porto e 18 em Lisboa onde foi avaliada novamente a saúde respiratória dos residentes em conjunto com a QAI e a qualidade da ventilação. O presente artigo pretende apresentar os primeiros resultados de uma campanha experi-mental realizada durante os meses de Fevereiro e Março de 2014 na fase II, com o objectivo de caracterizar as taxas de renovação horária em 15 ERPI, sendo 11 em Lisboa e 4 no Por-to. Na sequência do trabalho realizado, que consistiu em realizar medições com recurso ao método de gás traçador (técnica PFT) ao longo de períodos de tempo de duas semanas, fo-ram determinadas as taxas de renovação horária num número de quartos seleccionados que varia de 2 a 27, conforme a dimensão dos edifícios. Este projecto tem o apoio da Fundação para a Ciência e Tecnologia (PTDC/SAU-SAP/116563/2010).

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Due to the introduction of distributed renewable energy technologies with variable resource availability, the need of flexible electrical systems is evident. In general, flexibility is achieved from the supply side and often using carbon intensive energy generators. Therefore, improving the flexibility of the electrical system by taking advantage of renewable energy generation capacities and demand response measures in buildings is of major importance for a sustainable development. Control systems to implement these demand response measures need to quantify the flexibility of the respective buildings. Having this into consideration, this paper aims at presenting a literature review on methodologies to quantify the energy flexibility of buildings.

This paper describes field measurements of indoor air quality (IAQ) parameters, performed in 19 Portuguese Children Day Care Centers (CDCC) during the springtime of 2011 and aims to characterize the indoor environment. The results demonstrate an association between carbon dioxide and bacterial concentrations, which in turn are affected by the number of children present in each classroom. Indoor PM10 concentrations were higher than outdoor levels (I/O ratio>1) and was also found statistically significant association between PM10 concentrations and the type of floor covering materials. These results provide evidence that IAQ is inadequate and, as a consequence, human source contaminants such as bacteria and carbon dioxide accumulate indoors. This study suggests that it is necessary to improve ventilation in order to achieve a healthier indoor environment. Fundação para a Ciência e Tecnologia

É do conhecimento geral que a qualidade do ar interior influencia a qualidade de vida dos ocupantes dos edifícios e que pode ter implicações significativas no seu estado de saúde. As crianças constituem um grupo de risco que pode apresentar vulnerabilidades quando exposto a um ambiente interior de menor qualidade. Neste âmbito, correntemente constata-se que parece haver uma tendência para as crianças adoecerem com maior frequência quando iniciam a sua exposição ao ambiente de creches e infantários, ocorrendo em especial um aumento das doenças do foro respiratório. O projeto ENVIRH, reunindo uma equipa multidisciplinar, tem por objetivo principal estabelecer associações entre as condições de ventilação desses locais, a qualidade do ar interior (QAI) e a prevalência de doenças do foro respiratório. O projeto desenvolve-se essencialmente através de duas fases. De entre um total de 48 creches e infantários (Instituições Privadas de Solidariedade Social - IPSS) em Lisboa e 40 no Porto, foram selecionadas aleatoriamente 45 IPSS (sendo 25 em Lisboa e 20 no Porto), tendo sido analisadas na fase preliminar as suas condições construtivas, realizadas medições pontuais e instantâneas do teor de CO2 em salas de atividades, realizado um inquérito aos hábitos dos ocupantes relacionados com a ventilação e realizado um questionário médico para identificação de sibilância baseado no questionário ISAAC (International Study on Allergy and Asthma in Childhood). Com base na análise dos resultados preliminares, através do desenvolvimento de uma análise de “clusters”, foi selecionado um conjunto mais restrito de 20 IPSS, as quais integraram a segunda fase do estudo, onde foram realizadas medições das taxas de ventilação (método PFT), da QAI (CO2, CO, formaldeído, COVTs, PM10, bactérias, fungos e ácaros), do conforto térmico e feito um acompanhamento das condições de saúde das crianças (questionário médico, recolha de condensado brônquico do ar exalado,identificação de vírus respiratórios). A análise estatística dos resultados da primeira fase evidencia uma clara associação do incremento do teor de CO2 com as práticas de manter as janelas exteriores e as portas interiores fechadas (que reduzem as taxas de ventilação) e, por outro lado, uma associação do incremento do teor de CO2 com a sibilância (sintoma de doença respiratória). Esta comunicação detalha a metodologia seguida no estudo e apresenta os resultados da primeira fase.