English

Carbon dioxide concentration, indoor air temperature and relative air humidity are studied in 7 schools with natural ventilation systems, during 58 days on one year. The results show that the level of 1500 ppm of CO2 is exceeded in 39 days. A software programme was developed to calculate the CO2 concentration level according to the number of pupils and the ventilation rate.
Health problems may result from a too low ventilation rate.

The use of house dust is studied to identify sources and quantify levels of toxicants for the estimation of exposure. Sampling strategies were examined, just as uncertainty and lack of knowledge. The presentation of the results of sampling is also discussed. This article describes case studies.

A survey was carried out in 16 libraries in Modena University (Northern Italy) to assess the indoor exposure to Volatile Organic Compounds. VOCs were present in all the investigated libraries.The conclusion of that study is that no major problems were related to indoor pollution but the identification of the possible sources of contaminants is important, just as a definition of the relationship between indoor and outdoor levels of pollutants : that will take into account the effects of air recycling due to natural ventilation systems.

The changes in occurrence and the distribution of airborne fungi when they are transported in the airstream from the outdoor air to the indoor air are not well-known. For that study, fungal samples were tested in different locations in the HVAC systems with a six-stage Andersen Sampler with malt extract agar. The results showed that the fungal species changed according to those locations.

One of the major means of air diffusion for air conditioning equipment is the displacement ventilation. The stack effect is used by introducing at a very low speed, in the lower part of the room, some air whose temperature is close to the one of the desired atmosphere.

This paper proposes a space zone model for the calculation of all the airflow parameters based on tracer gas measurements, including flow rates of outdoor air, VAV supply. This approach gives a practical protocol for buildings managers to evaluate the performance of airside systems and determine air-conditioning and ventilation system performance parameters within acceptable errors.

Accurate mathematical models of airborne infection are needed to estimate the risk from secondary transmission of biological warfare agents. An equation has been derived by the authors : they determined the fraction of inhaled air that has been exhaled previously by someone in the building by using a CO2 concentration as a marker for exhaled-breath exposure.
There is a critical rebreathed fraction of indoor air below which airborne propagation of common respiratory infections and influenza will not occur.

This study was carried out in nearly two hundred multi-family buildings, built before 1961, in Stockholm. Three thousand inhabitants answered first a questionnaire on symptoms and personal factors. In parallel energy saving measures and building characteristics were gathered. It appeared that major reconstruction of the interior were associated with an increase of some symptoms.

This paper is a sum up of 32 epidemiological studies (mainly concerning children) having a link between indoor pollutions and respiratory diseases. Data issued from questionnaires and data from environmental measurements from these studies are compared and analysed.
Associations between different characteristics of the dwellings and respiratory symptoms are found. On the other hand, for factors like sociodemographic environment, heating and cooking installations, the impact on respiratory health is inconstant.

The inhabitants of Central Europe spend more of their time indoors. And indoor pollutants often affect human health more than the outdoor pollutants. This study aims at analysing how the indoor size distributions of submicron and ultrafine particles depends on outdoor distributions.
In the absence of indoor sources, concentrations of particulates are lower than in outdoor concentrations.