Ventilation and Measured IAQ in new US homes

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.

Impact of construction stages on Indoor Air Quality

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).

Transfer of ultrafine particles and air in multi-storey buildings

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.

Impact of the filtration system on the indoor-outdoor particles concentration relationships in an air conditioned office building

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.

Studying the Effect of Indoor Sources and Ventilation on the Concentrations of Particulates in Dining Halls

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.

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.

Flow fields and particle trajectories in turbulent type clean rooms with different supply/exhaust air arrangements

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.

Numerical simulation and analysis of particle movement in ventilation systems.

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.

Particles and displacement ventilation.

In displacement ventilation the airflow pattern in a room is mainly guided by the convection flows from the heat sources present in the room. This implies that the air in the breathing zone mostly comes from the lower parts of the room, where the air often is less polluted by pollutants originating from persons or electrical appliances present in the room.

A particle streak tracking system (PST) to measure flow fields in ventilated rooms.

The Particle Streak Tracking System (PST) is a fast method to measure two- and three-dimensional velocity fields in room air flows with measuring areas up to 5 m2. The two-dimensional method works with a single pulsed white light sheet and one digital camera. For three-dimensional velocity measurements in planes a laser light sheet system using three separate laser sheets with two different wavelengths and two CCD-cameras is employed. To visualise the flow helium filled bubbles are used. A description of the set-up will be given and the data evaluation process will be explained.