Etude des performances d'un système de ventilation hybride en France (Study of the performances of an hybrid ventilation system in France)

For that study, a classroom was modelled and a comparison of the performances of a specific hybrid ventilation system with a traditional mechanical system in terms of thermal comfort, indoor air quality concerning the CO2 concentration and energy consumption was made. The experiment was performed in different French cities, it permitted to draw some conclusions about the potential of such an hybrid system according to the main climate characteristics.

Exposure to environmental tobacco smoke in restaurants with separate ventilation systems for smoking and nonsmoking dining areas

The aim of this study is to compare the exposure to environmental tobacco smoke (ETS) of people in smoking and nonsmoking dining room. Levels of airborne pollutants and changes in urinary cotinine and nicotine levels were examined for 8 restaurants and 97 nonsmoking subjects (employees, patrons and referents).
Levels were significantly lower in the nonsmoking dining areas than in the smoking areas, and for the patrons than for the employees.

An investigation of air inlet in simulating the dispersion of indoor contaminants via computational fluid dynamics

The aim of the study is to validate CFD approaches for the simulation of the dispersion of gases and vapors in an enclosed space at different flow rates, and to show the impact of one important determinant of simulation accuracy.CFD results and measurements were compared, showing a good correspondance for the pollutant concentration when the boundary condition was a profiled velocity inlet and not an uniform velocity inlet.

Indoor air quality and occupational exposures at a bus terminal

This article is a study of the air quality at a bus terminal. Presence and concentration of indoor air quality indices were determined by field surveys and sampling. Bus emission rates, occupational exposure and ventilation requirements to have a correct indoor air quality were simulated by mathematical model.
The results show that the natural ventilation rates are too low for having a good indoor air quality, and that pollutants emission varies with the temperature.

Domestic exposure to formaldehyde significantly increases the risk of asthma in young children

In that study, formaldehyde exposures was examined in relation to asthma for young children in western Australia. An association was shown by comparing results of respiratory questionnaire and skin-prick test, and results of formaldehyde, average temperature and relative humidity measurements.

A pilot investigation into associations between indoor airborne fungal and non-biological particle concentrations in residential houses in Brisbane, Australia

In this study, associations between concentration levels of airborne particles and fungi were examined in 14 houses in Brisbane. No association was found between the fungal spore and submicrometer particles or PM2.5 concentration, but a weak link was found between fungal and supermicrometre particle concentrations : similarity in behaviour lies in the relation of the contaminant with the distance from the source.

Performance of deterministic workplace exposure assessment models for various contaminant sources, air inlet and exhaust locations

This study compares the contaminant concentration obtained from simple models with contaminant concentration fields obtained from CFD simulations, for various rooms and source configurations. Airflow and contaminant distributions were simulated.

Revised air-exchange efficiency considering occupant distribution in ventilated room

This article defines a new air-exchange efficiency that takes into account the occupancy in each zone.. Cases studies are then described and show that the new efficiency can better evaluate the ventilation effect of the room.

Indoor particles and symptoms among office workers : results from a double-blind cross-over study

The aim of the article is to study the effect of removing small airborne particles in an office building.The standard particle filters were replaced with highly efficient filters. Occupants answered questionnaire weekly and multiple environment measurements were done.The enhanced filtration reduced the concentration of smallest particles, symptoms were not reduced, but performance-related mental states improved.

Breathing freely in schools - results and model approaches concerning the air quality in classrooms (In German)

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.

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