Highly-efficient balanced air flow ventilation systems increased from 5 to 50% in markets hare within six years for new residential buildings in The Netherlands. This success is based on the contribution of the system to energy performance in combination with cost effectiveness. Occupants¿ complaints indicate that installation and maintenance quality need further improvement. One of the complaints relates to particle deposition. For better understanding of the impact of ducted air on particle distribution, experiments were performed with a full scale system in a test chamber. The presented results focus on aerosols deposition in the heat recovery unit and in the ducts, including components like dampers, sound attenuators, tees and bends. The deposition was measured under different ventilation scenarios, for the particles of size range 0.7-15 micrometers. The results show high deposition rate: 10-40% for total number concentration and with over 80% deposition of the larger particles. The ventilation unit and the air transport components function as one large filter, even in a scenario when no filter was applied. The overall effect is that the air at inlet dampers in the chamber contains less particles, especially in the larger size ranges (>PM1). A remarkable but preliminary result is that in components with large variation in air velocity, for instance in sections with turbulent flow, the particle concentration is higher. The deposition is not stable: aerosols are both deposited and released, possibly as a result of these turbulent flows. This effect raises questions about the location of filters. As filters and ducts seem to have a similar effect on aerosols concentration, and filters at the air intake location do not prevent deposition in the ducts, the deposited layer still influences air quality. The recommendation is to give attention to filter systems in the inlet dampers in the occupied space as well.@en

Problem Statement Housing and health are interconnected. By measuring the health performance of housing, risks can be identified and measures to improve the health potential can be taken. A Checklist Ventilation Quality, published by the National Tenant Organization, has been a successful ¿action¿ promoting tool in The Netherlands. The tool gives insight in the technical quality of ventilation services and also in the quality of use. The tool improves the communication about ventilation, in relation to moisture, smell and mould problems. A spin-off is the development of the Checklist Healthy Housing, with a much broader focus than ventilation. What are the requirements of a tool that can be used both by tenants and home owners or housing institutions? How can this tool support better communication about health risks of housing and how can it promote remediation? Objective The objective of the study is to determine in what situations and how a Checklist Healthy Housing can identify health risks and promote better communication about health related technical features and occupant behavior. Method Performance evaluation requires the selection of a limited set of simple and robust performance indicators. These indicators must support both tenants and landlords to come up with the same results. To study health performance indicators, field data were collected in 325 dwellings. The indicators are selected by developing and validating models on high concentration and high exposure to house dust mite, mould, noise, nuisance and drinking water contamination. Results The Checklist Healthy Housing has been developed, ready for use in pilots. The checklist includes a protocol to inspect the house and the user patterns of the occupants on the basis of a set of indicators. The inspection does not require expert testing or measurements. The two important moments to use the tool is when people move out and into a different house or when complaining about maintenance and indoor environment. Conclusion The study of the relation between occupancy patterns, building features and health risk in dwellings resulted in a set of robust indicators that support a relatively simple diagnosis of health risk in housing. Because both occupant behavior and technical aspects are included, the tool has a potential to improve the communication between tenants and landlords about healthy housing.@en

Until now health impact assessment and environmental impact assessment were two different issues, often not addressed together. Both issues have to be dealt with for sustainable building. The aim of this paper is to link healthy and sustainable housing in life cycle assessment (LCA). Two strategies are studied: clean air as a functional unity and health as a quality indicator. The strategies are illustrated with an example on the basis of Eco-Quantum, which is a Dutch whole-building assessment tool. It turns out that both strategies do not conflict with the LCA methodology. The LCA methodology has to be refined for this purpose.@en

Healthy housing strategies tend to focus on good comfort and on avoiding specific health risk agents. These agents are generated by building features and occupancy and may come from both indoor and outdoor environments. This research project focuses on building features and the impact they have on the indoor environment. The interaction between the building and occupancy patterns is studied. This paper describes the selection of the smallest set of indicators that allows a simple but effective evaluation procedure of the health performance of housing. The indicators are the markers of the main health risk agents in the house: mould, house dust mite, radiation, Legionella pneumophila, aerosols, noise and injuries. A health performance evaluation tool is being designed on the basis of these indicators. The tool can support the design of housing retrofits and maintenance policy in the housing stock. The research connects health risk and building quality assessment and is situated in the field of sustainable building.@en

We spend one third of our life in a bedroom and hardly question the health issues of the indoor environment. Occupants know little about the ecology of the house dust mite, about how to avoid mould problems, how to ventilate for good indoor air quality. The bed is likely the main source of house dust mite allergen in the house. Under the sheets air pollutants can reach a 50-fold concentration, compared to the indoor air. Sleeping with two persons in a small bedroom with closed door and no inlet of fresh air causes high moisture and pollutant levels. How healthy is the bedroom? The research on bedrooms is part of a research project on indicators of healthy housing. One of the results of this project is that indicators have to be selected for each different room in a house and that the bedroom is important because of the long exposure period.@en

This study focuses on the influence of the use of air inlet and exhaust devices on the air change rates per hour (ACH) in 37 residential dwellings in the Netherlands. The ACH in living rooms varied from 0.1 to 1.9, whereas in bedrooms it varied from 0.1 to 3.6. Computations of relative humidity and carbon dioxide using a simple mathematical model and measured values of ACH revealed risks of poor indoor air quality in bedrooms and bathrooms. In building regulations more attention should be paid to ventilation requirements for bedrooms and bathrooms.@en

Performance evaluation receives much attention from indoor specialists and from occupants. The paper presents a theoretical framework for the strategy of designs for instrumentation for health performance evaluation. Performance evaluation requires the selection of a set of simple and robust indicators. The health topics that are covered by these indicators are indoor air, risk of injury, functional and thermal comfort, acoustics, safety and social quality. Problem solving is placed in the context of performance management of housing, Communication between the housing manager and the occupant, while dealing with complaints and identifying who is responsible actions, is essential in the framework.@en

Mould on interior surfaces is correlated with adverse health effects. The aim of this study was to formulate measures to avoid moulds in bathrooms. These measures were based on the relationship between housing characteristics and mould growth. We investigated 75 housing characteristics and the occurrence of mould in 186 dwellings in The Netherlands. The relationship between housing characteristics and mould was investigated by means of bivariate correlation and logistic regression analysis. The number of showers (> 14 per week) taken by the occupants and the age of the ventilation box (> 6 years) were found to be the most important predictors of mould growth in bathrooms. The results show that 80% of the values predicted by the logistic model agreed with the observations. To keep the risk of mould growth at a minimum level, the maintenance frequency of the ventilation fan box should be at least every 5 years and the number of showers per week per bathroom should not exceed 14.@en

We spend 30-40% of our life time in the bedroom, well secured from the outdoor environment, but is the indoor environment secure and healthy? The bedroom is probably the most important place in our home. While asleep, we do not act in control of the environment. It affects us, but in the morning we walk away from it. The paper focuses on the indoor climate of the bedroom. The bedroom is often poorly ventilated, full of house dust mite allergen, and with daily peak levels of other pollutants.@en

Moisture problems in dwellings are widespread, yet there is no clear understanding of the moisture balance. A balance sheet is produced, based on experimental data. The balance sheet helps to identify conditions with high risk of mould growth and high house dust mite population growth.@en

The quality of indoor air is linked to detrimental health effects. Indoor air is a research and design issue in healthy housing, rarely considered in sustainable building. By analysing the relation between sustainable building and indoor air, a framework for discussion is constructed. The question is how the relation between healthy indoor air and sustainable building can be improved. The authors conclude that fresh air can be treated as an essential consumption good, which is produced by building services. Fresh air must be ¿created¿ in situations when the collected outdoor air needs to be filtered, heated, transported, consumed and replaced. After its use, the air is exhausted as waste material. The energy consumption, pollution process and re-cycling can be accounted for in life cycle assessment calculations. From the perspective of flows, airflows can be added to the flows of materials, energy and water during the entire life cycle of the building. The integration of flows in terms of consumption of fresh air will result in a better balance between strategies on the level of each flow. In this way it will be possible to make a stronger link between healthy indoor air and sustainable building.@en

This paper describes a study of reduced performance of mechanical exhaust systems in 42 Dutch houses after several years of operation. It also describes the effect of reduced ventilation on air quality and the perception and use of the ventilation system by residents. The guanine contents of dust samples taken from the sleeping room were determined to assess the risk of allergy. In 93% (n=42) of the houses the reduction of the exhaust rate was more than 10% of the value demanded by Dutch building regulations that applied then the houses were built. Deterioration of the system started within 2 years. After 5 years the average reduction of the exhaust rate was 50% of the initial rate. Interviews of the residents revealed that the systems could not be cleaned and maintained easily. Grids and fanlighte in the vicinity of seats and benches were in a closed position because residents fear cold draught. To avoid noise production, residents selected the lowest speed of the exhaust fan. They did not know that the minimum ventilation demands are only met at the highest speed level.@en