particles

The relation between the concentration and particle size of the human breathing and the way in which these particles are dispersed in hospital indoor environments are studied in this research. Breathing thermal manikins are used to, experimentally, simulate a human person and its breathing activity. Two breathing thermal manikins are placed in a hospital room, simulating an infected patient, together with another standing manikin simulating a health worker.

Indoor Air quality (IAQ) of dwellings is the result of several sources and processes, and the impact of ventilation system is the one amongst many others. Definition and metrics of IAQ are several and we choose in this study to focus on airborne particle levels. Our question was: How the filtration of supply air impacts particle levels in indoor air?  

As newer homes are being built tighter than the existing housing stock, questions have been raised about the concentrations of pollutants of concern in new homes and how mechanical ventilation systems can address this issue. This study measured pollutants of concern in 70 new homes with mechanical ventilation in California, USA and compared the results to a previous study of home without mechanical ventilation. The key pollutants were measured using both time-integrated and time-resolved over a one-week period and included formaldehyde, PM2.5 and NO2.

Since the turn of the century, alarming data produced by the Indoor Air Quality Observatory (OQAI) have led to changes in French legislation, including, most notably, the introduction of compulsory labelling for construction products (decree no. 2011-321 of 23 March 2011).

An emerging issue in Denmark is passive smoking in residential buildings where non-smokers are exposed to harmful smoke from their neighbours. There are various ways that smoke infiltrates from one flat to another. The air infiltration rate between two flats in a multi-storey building depends on its construction, tightness and age.

The objective of this study is to measure the impact of various classes of filters in the HVAC system on the IAQ in an office building. It aims at understanding outdoor-indoor concentrations and filtration relashionships in order to guide filtration system designs.

The impact of ventilation on indoor particulate pollution is highlighted by numerous studies. The aim of the present study is to examine the influence of ventilation on the levels of particulate concentrations found in dining halls where a large number of students are accommodated. Indoor particulate sources were also quantified and their influence on the particulate concentrations was examined.

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.

A wall return and a ceiling return air arrangements of turbulent type clean rooms are presented in this paper. The influences of obstacles on the flow fields are compared by a numerical simulation.

A mathematical model has been set up for the multizone structure region in this paper. By the way of numerical simulation, the analyses are conducted of air flow and aerosol particle travel under the mechanised ventilation condition. The results of such analyses provide useful data for ventilation system design and the indoor air quality control.