Measurements of indoor air pollutants covering the concentrations of CO2, CO, TVOC’s, PM2.5, and PM10 were performed in 50 residences in Athens. In addition the ventilation rate in each dwelling was continuously measured by monitoring CO2 concentration. Apart from carbon monoxide, almost all the remaining pollutants showed high concentrations that exceeded the maximum threshold levels of the relevant standards. The rate of ventilation was found to have a very important impact on the concentration of indoor pollutants.

The UK climate is moderately mild and natural ventilation by window opening and passive ‘trickle’ vents is very common. In this paper the natural ventilation rates provided by top-hung windows open to small angles in single-sided designs have been studied using a common whole building simulation tool. It was found that the amount of ventilation greatly depends on how the windows are represented. Such software tools usually assume that the opening area has the same vertical separation as the underlying window (i.e. it is modelled as an arrow slit).

The requirements for good indoor air quality and energy efficiency have often been considered to be in conflict with each other. However, buildings with low energy consumption in Europe also seem to have a lower rate of building related health symptoms. This indicates the importance of proper design and installation as well as qualified, well trained operational personnel, who understand both the requirements for good indoor air quality and energy efficiency. Several strategies for ventilation are described in this paper.

There is a wide range of factors that influence natural ventilation. The uncertainties arising from theunpredictable nature of wind lead to the need to account for periods of time when winds are unable to provide indoor summer comfort. Some methods for estimating natural ventilation are outlined together with the effects of high site coverage, building porosity, insect screens, and local wind shelter from adjacent houses and vegetation. Indoor wind speed coefficients provide a direct method for comparing the natural ventilation potential of housing stock.

Roof thermal performance is one of the most important factors for achieving indoor thermal comfort in a tropical house designed for natural cross ventilation. This study, based on field study data, discusses roof design strategies for a hot-humid climate by investigating the impacts of roof thermal performance on indoor thermal comfort in a naturally ventilated house. Conventional roof design for tropical houses mainly focuses on the roofs day-time thermal performance for limiting solar heat gain through the roof structure.

The transmission of SARS in high rise residential buildings in Hong Kong has highlighted the importance of indoor environmental quality. One of the important parameters that requires investigation is natural ventilation. The air change per hour (ac/h) of living rooms was studied in two newly constructed vacant tall buildings in Hong Kong. The aim was to benchmark the air change rate of high rise residential buildings. The scope of the work covered the measurement of air change rate in living rooms under both natural ventilation and air conditioning operation.

Convective heat and mass transfer through large internal openings play an important role in the aero-thermal behaviour of buildings. These phenomena become even more dominant in the case of naturally ventilated buildings. The three-dimensional zonal model of coupled heat transfer and air flow calculations ZAER (Zonal AERial model) has been extended to enable predictions of variations in temperature distributions and airflows between and within rooms subjected to natural convection.

Indoor microbial exposure has been implicated in various adverse health effects. This study aimed toexamine the effects of ventilation efficiency on indoor/outdoor (I/O) levels of airborne microbes in homes with natural ventilation, a predominant type adopted by most residential buildings in Taiwan where high microbial concentrations have been reported. Environmental investigations were conducted in 44 homes. Indoor and outdoor airborne bacteria and fungi were collected using a Burkard sampler with Trypticase Soy agar and Malt Extract agar in a flow rate of 10 L/min.

The airflow rate of a building ventilated by wind is usually predicted by using the wind pressure coefficients obtained for a sealed building and discharge coefficients based on measuring the airflow characteristics through an opening in a sealed chamber (chamber method). This can result in the underestimation of wind driven flow through large openings located on opposite sides of a room. In this paper, the discharge coefficient, based on the chamber method, and the actual condition of cross-ventilation are calculated and compared with each other by means of stream tube analysis.

This paper attempts to look at the unsteady flow pressure on the blade tip in order to quantify the inception of instability of an axial-flow ventilation fan. A test rig was set up to measure the unsteady static pressure near the rotor blade tip region by mounting several transducers on the outer casing. The data sampling system was configured for acquisition and post analysis. The measurement results showed that, as the throttle was closed, the flow disturbance appeared firstly at the rotor inlet.