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This field study is investigating the impact of residential ventilation rates on indoor air quality (IAQ) and the respiratory health of asthmatic children in Québec City. The objective of this study is to determine whether an increase in ventilation will lead to a corresponding decrease in the number of asthmatic symptoms in children, to correlate ventilation rates with IAQ, and to support research for determining health-based ventilation rates. There are currently 84 children, living in single-family homes, participating in this study.
This activity is a three year multi-partner project between NRC’s Institute for Research in Construction, Québec’s Institut national de santé publique du Québec (INSPQ), the Centre Hospitalier Universitaire du Québec (CHUQ) and the Canada Mortgage and Housing Corporation (CMHC). The design of this study was guided by a Scientific Steering Committee consisting of research scientists and physicians from NRC, INSPQ, Health Canada, CHUQ and CMHC. INSPQ is responsible for the recruitment of the participants and monitoring the health of the asthmatic children while NRC is responsible for measuring the IAQ and ventilation rates. A Task Group on Ventilation, which was lead by CMHC and included members from NRC and INSPQ, was responsible for the design and implementation of the ventilation interventions.
During the initial (pre-intervention phase) of the study the homes of the children were visited by NRC staff to measure a number of IAQ relevant physical, chemical and biological parameters, as shown in Table 1, over three separate one week periods.
| Table 1: Overview of the IAQ Parameters Measured in this Study | ||
| Physical | Chemical | Biological |
| Relative Humidity | Ozone (O3) | Endotoxins in house dust |
| Infra-Red Thermography | Nitrogen Dioxide (NO2) | Glucans in house dust |
| Aerosol (fine and ultra-fine) | Aldehydes | Ergosterol in house dust |
| Air infiltration | Carbon Dioxide (CO2) | Mould
|
| Temperature (air & building envelope) | Semi-volatile Organic Compounds in Dust | Allergens in house dust
|
| Air flow rate at registers | Volatile Organic Compounds in Air
|
|
Air Exchange Rate
|
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The chemical and biological samples were then sent to IRC’s analytical chemistry and mycology laboratories for analysis. The field technicians also recorded the physical characteristics of the homes, such as the layout, construction and ventilation system and administered questionnaires relating to occupant behavior, housing characteristics and the indoor environment of the home.
Figure 1: (A) Instrumentation for conducting an SF6 tracer gas decay test along with a typical result obtained from a participant’s house, (B) an NRC researcher conducting an air infiltration measurement.
Following the pre-intervention phase, the homes with low air exchange rates were provided with supplementary ventilation through the installation of a heat recovery ventilator. The interventions were modeled computationally and physically at NRC’s Indoor Air Research Laboratory to ensure that the intended increase in ventilation would be achieved.
The post-intervention phase, where the IAQ, ventilation rates and health of the children is monitored in both the control and intervention groups, is identical to the pre-intervention phase. The post-intervention phase will be used to assess the effectiveness of the intervention in improving the IAQ and respiratory health of the asthmatic children. To date, 83 homes are undergoing their post-intervention visits, of which 40 are serving as the control group having not undergone an intervention, and we are scheduled to complete the final summer visits by the end of September. The Scientific Steering Committee will be in a position to provide recommendations on how ventilation rates affect the health of asthmatic children once all the medical and indoor air quality data is fully analyzed in 2012.
This study was funded through the Government of Canada’s Clean Air Agenda in order to increase knowledge of the risks, health impacts and mitigation strategies related to indoor air quality, and reduce the adverse health effects of poor IAQ on Canadians. The NRC team would like to thank Don Fugler (CMHC) for his strong engagement and the use of his long-standing experience in theis area and as well welcome Ken Ruest (CMHC) on board of the research team.
Preliminary results from the field study have been presented at the following conferences and have resulted in the following client reports;
- Preliminary results from a field study investigating the impact of ventilation rates on indoor air quality and the respiratory health of asthmatic children in Québec city
Aubin, D. Won, D.Y. Schleibinger, H. Gauvin, D. Lajoie, P. Fugler, D.
Air and Waste Management Association's 103rd Annual Conference (Calgary, Alberta, 2010-06-22), pp. 1-6. - Preliminary comparison of air change rates measured in Quebec City homes using SF6 and perfluorocarbon tracer gases and blower door test results during the winter season of 2008-09
Aubin, D. Gauvin, D. Won, D.Y. Schleibinger, H. Fugler, D.
Healthy Buildings 2009, 9th International Conference and Exhibition (Syracuse, New York, 2009-09-13), pp. 1-4. - Seasonal variation in indoor air quality from a field study investigating the impact of ventilation rates on the health of asthmatic children in Québec City,
Aubin D.G., Won D., Schleibinger H., Gauvin D., Lajoie P., Fugler D.
Accepted for Presentation and publication in the conference proceedings at the Indoor Air 2011 Conference in Austin, Texas, 5-10 June, 2011 - Comparison of air exchange rates measured with different methods and influencing factors: preliminary results of a field study involving asthmatic children,
Won, D.Y.; Aubin, D.; Fugler, D.; Gauvin, D.; Lajoie, P.; Schleibinger, H.
12th International Conference on Indoor Air Quality and Climate (Austin, Texas, June 5, 2011), pp. 1-6, - Issues Related to the Use of CO2 as an indicator of Ventilation
B3335 (Client Report for Health Canada, March 2011) - Comparison of Methods for Characterizing Air Exchange Rates
B3328.1 (Client Report for CMHC, March 2011)
For more information, contact Daniel Aubin or Tel: 613-998-8551.
