Potential determinants of exposure to culturable airborne fungal and bacterial
aerosols and carbon dioxide were examined as an aid to the interpretation and evaluation
of indoor air quality assessments. Concentration measurments for culturable bioaerosols
and CO2 were evaluated against published standards and guidelines.
METHOD: All 39 schools from one British Columbia school district were enrolled in the
study to ensure different building ages and construction materials, but the same
maintenance protocols, were included. Schools were randomly assigned to winter, spring
or fall sampling. Data collected included: number of occupants and patterns of
occupancy, CO2 levels, temperature and relative humidity, total suspended particles, and
air exchange rates using tracer gas (SF6) decay. Other characteristics of the classrooms
included the presence or absence of forced air heat, carpets, live animals or aquaria,
plants, and the siting of the school or portable classroom. Culturable indoor and outdoor
aerosols of fungi and bacteria were collected. Determinants of exposure were modelled
by constructing multiple linear regression equations for indoor fungi, indoor bacteria and
indoor carbon dioxide.
RESULTS: The multiple regression models were able to explain a considerable
proportion of the variance for the outcomes of interest (total R2 = 0.59 for mesophilic
fungi, 0.61 for bacteria, and 0.68 for CO2). Increased outdoor temperature and outdoor
fungal counts were associated with higher concentrations for indoor fungi. Variables
describing ventilation and conditions of occupancy were significant to all outcomes of
interest but functioned differently in the models. For example, fungal concentration was
higher in the presence of natural ventilation, but lower with increased mechanical
ventilation. In contrast, CO2 was lower with both ventilation types, and lower with higher
outdoor temperature.
CONCLUSIONS: Using variables measured during an indoor air quality investigation,
predictive models can be constructed which are useful in identifying determinants of
bioaerosol and bioeffluent concentrations. Ranges of bioaerosol and bioeffluent
concentrations for high occupancy buildings in a coastal temperate zone may differ from
guidelines written for other indoor settings and climate zones.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:BVAU.2429/11367 |
| Date | 05 1900 |
| Creators | Bartlett, Karen Hastings |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Relation | UBC Retrospective Theses Digitization Project [http://www.library.ubc.ca/archives/retro_theses/] |
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