English

Domestic gas apparatus generate oxides of nitrogen (NOx), which have been classed in recent years as problem products in the context of indoor air quality (IAQ). These, together with carbon monoxide which may also be present in the products of gas combustion, mean that the formulation of regulations for health protection presents complex problems. The present work shows the importance of this matter and presents interesting case studies taken from the Basque Country and our area of influence. It also makes specific recommendations as to how existing regulations should be changed.

This paper provides a discussion on the use of the olf and the decipol. The validity of using these units to determine ventilation rates and compare pollution emission rates is discussed, in relation to their derivation and theoretical basis and the method of application. A procedure has been developed for testing buildings by using a trained panel of people to rate air quality directly in decipol units. This was used in nine European countries as part pf the 'European Audit Project'.

During the period August 1993-0ctober 1994 a study was undertaken throughout British Telecommunications pie to assess occupational exposure to radon. This paper is concerned only with that portion of the work concerned with underground structures. The results show that radon can build up to very high concentrations in manholes and implies a significant risk to those who need to work in them.

A major increase of complaints has been observed by the occupants of buildings, concerning health symptoms and comfort. In this study, the occupants' experience of symptoms as well as the occupants' sensation of the environmental parameters were estimated in six office buildings, where the indoor air quality was investigated. It was found that the percentage of building related symptoms experienced by the occupants of the buildings was high and it was strongly related to human comfort and human sensation concerning the environmental conditions.

Thermal comfort and air quality were studied in three multi-family buildings located in urban environments. Measurements of air velocities close to the supply devices are presented along with measurements of CO, TVOC, NO and N02. In addition, particle measurements were carried out to check the filter efficiency in one of the buildings (Sl) which is specially designed for people with allergy problems. The total air change rate for this building is higher than for normal residential buildings and three different types of air filter are installed in the ventilation system.

The concept of ventilation effectiveness for mechanical ventilation of an airspace is reviewed and associated parameters for describing the performance of ventilation systems are described. The idea is applied to a study of the thermal environment in the waiting hall of a railway station. Two ventilation schemes: one with a ventilation system only and the other with an air-conditioning system were considered. The proposed air-conditioning system would provide air at a temperature only 5 °C below the ambient but with a higher air circulation rate.

The connection between health and cleanliness is, for most people, a matter of common sense. Office workers report higher rates of discomfort when they perceive a dirty, dusty environment. Research, not surprisingly, shows that certain cleaning methods are effective in reducing dust on surfaces and in reducing the levels of indoor air contaminants. Yet some cleaning practices, like the use of improperly diluted cleaning solutions, are themselves significant threats to good IAQ. As with everything else, there are right and wrong ways to clean.

 The exposure of workers in the near-wake region due to a recirculating airflow was studied experimentally and numerically. A mannequin was installed in an open-ended tunnel and tracer gas was released at several locations downstream to determine the size and location of the reverse flow region. The contaminant transport into the breathing zone was found to depend strongly on the location of the release point. The airflow field was also determined numerically assuming a steady 6ow and using the standard k-£ turbulence model.

Personal exposure in a displacement ventilated room is examined. The stratified flow and the considerable concentration gradients necessitate an improvement of the widely used fully mixing compartmental approach. The exposure of a seated and a standing person in proportion to the stratification height is examined by means of fullscale measurements. A breathing thermal manikin is used to simulate a person. It is found that the flow in the boundary layer around a person is able to a great extent to entrain and transport air from below the breathing zone.