Investigating measurements of fine particle (PM2.5) emissions from the cooking of meals and mitigating exposure using a cooker hood

There is growing awareness that indoor exposure to particulate matter with diameter ≤ 2.5μm (PM2.5) is associated with an increased risk of adverse health effects. Cooking is a key indoor source of PM2.5 and an activity conducted daily in most homes. Population scale models can predict occupant exposures to PM2.5, but these predictions are sensitive to the emission rates used. Reported emission rates are highly variable, and are typically for the cooking of single ingredients and not full meals. Accordingly, there is a need to assess PM2.5 emissions from the cooking of complete meals. Mean PM2.5 emission rates and source strengths were measured for four complete meals. Temporal PM2.5 concentrations and particle size distributions were recorded using an optical particle counter (OPC), and gravimetric sampling was used to determine calibration factors. Mean emission rates and source strengths varied between 0.54—3.7 mg/min and 15—68 mg, respectively, with 95% confidence. Using a cooker hood (apparent capture efficiency >90%) and frying in non-stick pans were found to significantly reduce emissions. OPC calibration factors varied between 1.5—5.0 showing that a single value cannot be used for all meals and that gravimetric sampling is necessary when measuring PM2.5 concentrations in kitchens

Design and performance predictions of plus energy neighbourhoods – Case studies of demonstration projects in four different European climates

The article presents the design of four plus energy neighbourhood demonstration projects located in different climate zones in Europe. The demo projects are a part of the Horizon 2020 project ‘syn.ikia’, which aims to enable the development of sustainable plus energy neighbourhoods in different climates and contexts. In this article, we describe the active and passive building strategies and analyse the robustness of the designs with respect to different scenarios of climate change, user behaviour, and energy flexibility. Analyses were performed based on the primary energy balance, including space heating and cooling, ventilation, domestic hot water, and lighting. The performance predictions indicate that all demonstration projects may attain the plus energy balance according to the syn.ikia definition. This was achieved with high performing envelopes, efficient HVAC systems, and onsite renewable energy systems to cover the energy demand. The analysis shows that there is a significant potential for increased self-consumption of photovoltaic energy by adjusting the heating schedules and including electric vehicle charging. Testing of the designs with respect to varying climates and user-behaviours showed that there could be an increased risk of overheating, and that some of the designs may not achieve the positive energy balance in case of ‘worst case’ user behaviour scenarios.publishedVersio

Tuning the energetics and tailoring the optical properties of silver clusters confined in zeolites

The integration of metal atoms and clusters in well-defined dielectric cavities is a powerful strategy to impart new properties to them that depend on the size and geometry of the confined space as well as on metal-host electrostatic interactions. Here, we unravel the dependence of the electronic properties of metal clusters on space confinement by studying the ionization potential of silver clusters embedded in four different zeolite environments over a range of silver concentrations. Extensive characterization reveals a strong influence of silver loading and host environment on the cluster ionization potential, which is also correlated to the cluster's optical and structural properties. Through fine-tuning of the zeolite host environment, we demonstrate photoluminescence quantum yields approaching unity. This work extends our understanding of structure property relationships of small metal clusters and applies this understanding to develop highly photoluminescent materials with potential applications in optoelectronics and bioimaging

A multidisciplinary perspective on COVID-19 exit strategies

Lockdowns and associated measures imposed in response to the COVID-19 crisis inflict severe damage to society. Across the globe, scientists and policymakers study ways to lift measures while maintaining control of virus spread in circumstances that continuously change due to the evolution of new variants and increasing vaccination coverage. In this process, it has become clear that finding and analysing exit strategies, which are a key aspect of pandemic mitigation in all consecutive waves of infection, is not solely a matter of epidemiological modeling but has many different dimensions that need to be balanced and therefore requires input from many different disciplines. Here, we document an attempt to investigate exit strategies from a multidisciplinary perspective through the Science versus Corona project in the Netherlands. In this project, scientists and laypeople were challenged to submit (components of) exit strategies. A selection of these were implemented in a formal model, and we have evaluated the scenarios from a multidisciplinary perspective, utilizing expertise in epidemiology, economics, psychology, law, mathematics, and history. We argue for the integration of multidisciplinary perspectives on COVID-19 and more generally in pandemic mitigation, highlight open challenges, and present an agenda for further research into exit strategies and their assessmen

Ventilation challenges in a changing world

More than ever in the past, climate change and the transition to carbon neutrality are at the center of many countries´ policies and research programmes. The building sector plays a crucial role in achieving these goals, considering the carbon emissions attributed to buildings’ construction and operation, and its potential for better energy performance. At the same time the COVID-19 crisis has emphasized the need to improve indoor air quality (IAQ) and ventilation in our buildings to reduce the risks of airborne virus transmission. All these challenges require a transformation of the existing building stock that at the same time achieves better IAQ and lowers environmental impact. In 2022 the Air Infiltration and Ventilation Centre organizes its first international conference since the beginning of the COVID-19 crisis. Therefore the conference organizers want to pay specific attention to the role of ventilation and infiltration in building decarbonization, and improvement of indoor air quality including epidemic preparedness. How can design, construction and renovation practices, innovative and digital technologies help in today’s challenges? This is the context defining the core theme of the joint 42nd AIVC, 10th TightVent and 8th venticool Conference: “Ventilation Challenges in a Changing World”. Withi

The development of an RC-network simulation model calibrated with monitoring data for use in the performance guarantee of Net-Zero houses

In order to drive forward the energy transition, construction companies and other suppliers of deep retrofitting solutions have started to give guarantees on the energy performance of very energy efficient houses. With these initiatives, a need has arisen for methods that can assess per household the actual energy performance during the use phase. An RC-network simulation model calibrated with monitoring data has been developed and tested on deep retrofitted Net-Zero houses in Emmen (the Netherlands). The results show that this has been a successful first step in order to arrive at a realistic analysis of the actual energy performance of individual houses. The big challenge will be to determine the parameters in the model with more certainty. This applies especially, but not exclusively, to the behavioural parameters

Design and performance predictions of plus energy neighbourhoods – Case studies of demonstration projects in four different European climates

The article presents the design of four plus energy neighbourhood demonstration projects located in different climate zones in Europe. The demo projects are a part of the Horizon 2020 project ‘syn.ikia’, which aims to enable the development of sustainable plus energy neighbourhoods in different climates and contexts. In this article, we describe the active and passive building strategies and analyse the robustness of the designs with respect to different scenarios of climate change, user behaviour, and energy flexibility. Analyses were performed based on the primary energy balance, including space heating and cooling, ventilation, domestic hot water, and lighting. The performance predictions indicate that all demonstration projects may attain the plus energy balance according to the syn.ikia definition. This was achieved with high performing envelopes, efficient HVAC systems, and onsite renewable energy systems to cover the energy demand. The analysis shows that there is a significant potential for increased self-consumption of photovoltaic energy by adjusting the heating schedules and including electric vehicle charging. Testing of the designs with respect to varying climates and user-behaviours showed that there could be an increased risk of overheating, and that some of the designs may not achieve the positive energy balance in case of ‘worst case’ user behaviour scenarios

Design and performance predictions of plus energy neighbourhoods – Case studies of demonstration projects in four different European climates

The article presents the design of four plus energy neighbourhood demonstration projects located in different climate zones in Europe. The demo projects are a part of the Horizon 2020 project ‘syn.ikia’, which aims to enable the development of sustainable plus energy neighbourhoods in different climates and contexts. In this article, we describe the active and passive building strategies and analyse the robustness of the designs with respect to different scenarios of climate change, user behaviour, and energy flexibility. Analyses were performed based on the primary energy balance, including space heating and cooling, ventilation, domestic hot water, and lighting. The performance predictions indicate that all demonstration projects may attain the plus energy balance according to the syn.ikia definition. This was achieved with high performing envelopes, efficient HVAC systems, and onsite renewable energy systems to cover the energy demand. The analysis shows that there is a significant potential for increased self-consumption of photovoltaic energy by adjusting the heating schedules and including electric vehicle charging. Testing of the designs with respect to varying climates and user-behaviours showed that there could be an increased risk of overheating, and that some of the designs may not achieve the positive energy balance in case of ‘worst case’ user behaviour scenarios

40 years to build tight and ventilate right : from infiltration to smart ventilation : AIVC Technical note 70

As the AIVC was created in 1979, the 40th anniversary of the AIVC was celebrated in October 2019 at the 40th AIVC conference in Ghent. In the context of this celebration, it was decided to publish 2 overview publications: An AIVC technote, which focuses on the overall history of the AIVC and those involved in the organisation (TN 69: 40 years to build tight and ventilate right: History of the AIVC) This publication, focusing on the main technical areas of AIVC's involvement during the past 40 years The AIVC was created in 1979 and started having annual conferences in 1980. The 2019 Conference was its 40th conference and the conference theme focused on its anniversary. This Technical Note is a compendium of the contributions that the AIVC has made in its first 40 years and reflects field’s evolution over time. Much of the information generated by the AIVC is of direct use today and some of the older material is good source material for future research. The AIVC is an information dissemination project created by the International Energy Agency (IEA) as a result of a need to understand the energy impacts from air leakage in buildings for the energy crisis of the 1970s. When the Center was first created it was called the Air Infiltration Center because the focus was on energy loss due to infiltration. It was generally thought that most buildings leaked way too much air and that reducing that infiltration would reduce dependence of fossil fuels. The mechanism the IEA uses to create projects is through implementing agreements of member nations. The AIC was the 5th project (or “annex”) created by the implementing agreement on buildings and community systems, which has been renamed Energy in Buildings and Communities (EBC) at https://www.iea-ebc.org/. There have been 70 projects completed from EBC and 17 that are on-going currently. Of those, Annex V is the only information dissemination center and the only one that is active for more than a few years. Because infiltration research was not a field of its own in the 70s, the AIC became the de-facto coordinating body for infiltration-related research around the world. It was sometimes difficult to understand each other, hence we started a series of TN named AIRGLOSS in which terms and definitions were described. When investigating a new area, the first thing one must do is be able to measure it. A significant effort was put into measurement techniques both for air change rate and for air tightness. The research community is much broader now, but these are still active areas of research. Chapter 3 discusses air tightness and Chapter 4 discusses air flow measurement techniques. Infiltration and air tightness are of course related, but quantitatively connecting air leakage and air flow, requires modeling and such models did not really exist. So along with a focus on measurement techniques, the AIC worked on infiltration modeling as discussed in Chapter 5. The first models were simple, physical models, but as computing power and the state of knowledge grew, so did the models. After only a few years, it became clear that looking at infiltration in isolation was a sub-optimal approach. As buildings were getting tighter, there was a concern of insufficient air exchange. An optimal energy solution would then need to include both infiltration and designed ventilation. Accordingly, annex V’s mandate was broadened to include ventilation systems and in the mid-80s the name was changed to the Air Infiltration and Ventilation Center as it remains. In 1985 the AIVC began publishing technical reports (e.g. TN 17) that specifically focused on optimal ventilation strategies. Many AIVC (and conference publications) have worked this problem in the last 35 years. Chapters 14 and 15 review many of the approaches used today. One of the more recent trends is to make our ventilation systems smarter and Chapter 13 looks at some aspects of that. It was also realized during the 1980s that occupant behavior had a bit impact with respect to ventilation overall. EBC Annex VIII focused on this and resulted in 1988 in AIVC TN23 on the topic. Early research focused on issues such as window opening, but later work looked at how mechanical systems are perceived and ran. Chapter 10 looks at occupant impacts from today’s perspective. Ventilation for acceptable indoor air quality generally uses energy to condition the outdoor air, but there are times when ventilation can save energy, if it displaces the need for mechanical cooling. Providing ventilative cooling can be through both mechanical and natural means and can positively impact comfort. Chapter 8 discusses these issues. As the AIVC was going to work on optimal ventilation strategies, it was important to know what the standards for acceptable ventilation were and this became another focus of the center’s work. The center has published many documents related to standards such at TN26 in 1989 that summarized EBC Annex IX. Ventilation standards have grown much more sophisticated since those times and are addressed in Chapter 9. One thing common to most ventilation standards over that period is that they assume that outdoor air is clean, or at least substantially better than indoor air. In such a case one can use it to dilute indoor-generated contaminants without worry. We know that in many cases this assumption is wrong, but it is not always clear what to do. Chapter 12 looks at the issue of outdoor air more broadly. Outdoor air contains moisture, but water vapor is a rather unique kind of contaminant: it has both an indoor and outdoor source and we neither want too much of it nor too little. Control of moisture has been a priority for the AIVC since it had a workshop in New Zealand (TN20) in 1987. Chapter 7 provides an overview the issue today. Another unique kind of constituent is carbon dioxide. CO2 is a product of combustion including human metabolism and therefore is unavoidable in indoor spaces. At high enough concentrations CO2 can become deadly, but it is not a contaminant of concern in typical buildings. It is, however, a good indicator that can be used in ventilation systems. Use and misuse of CO2 is a quite topical issue today. Chapter 11 discusses the role of CO2 in buildings. Since the turn of the century, it has been clear that the purpose of ventilation is acceptable indoor air quality and one cannot determine acceptable indoor air quality without looking at health. A growing part of the more recent efforts of the AIVC have been focused on understanding this health linkage and optimizing systems accordingly. Chapters 6 and 13 address what the AIVC has been doing in this area and form a basis for future activities