Personal and Microenvironmental Concentrations of Particles and Microbial Aerosol and Their Association with Health Symptoms Among Teachers

Abstract

P-023 Abstract: Eighty-one randomly selected elementary school teachers participated in two sampling campaigns conducted two weeks apart during the winter. A 24-hours sample collection was performed using both personal sampling and microenvironmental sampling from homes, and an 8-hour sample collection was performed from workplaces of the subjects. Filters were analyzed for particle mass, absorption coefficient, and for both total and viable microorganisms. Questionnaire responses were collected from the teachers immediately after each sampling campaign inquiring symptoms during the previous 7-day periods. Factor analysis was used in order to identify factors explaining the pattern of correlations within the personal, home, and work measurements. In factor analysis, components extracted from data related to A) personal exposure and B) concentrations of pollutants at home included three factors grouped together: 1) viable fungi, 2) particle mass and absorption coefficient, and 3) total fungi and bacteria. Thus, components formed reflected the type of exposure and/or analysis methods used. Total variance explained was 72.5% for A and 71.3% for B, and the percent of variance explained by each component was 20.9 – 28.9%, indicating main component loadings of similar magnitude. At work, the first component extracted was more mixed, including particle mass, total fungi and total bacteria, and viable bacteria. The second and third components included concentrations of viable fungi and absorbance coefficient, respectively. Total variance explained was 74.08%, and the percent of variance explained by each component was 15.5–31.5, indicating more variation in the main component loadings. Associations between personal, home, and work measurements of pollutants and symptoms were analyzed using General Estimation Equations. First, personal, home, and work environment related models containing only one pollutant together with the confounding factors (including age, gender, smoking and family atopy) were examined. Second, three pollutants considered independent from each other based on the factor analysis (including viable fungi, absorbance coefficient, and total bacteria) were included in the models at once. Both personal exposure and concentrations of pollutants at home were more frequently associated with health symptoms than concentrations at work. Positive associations were found between absorbance coefficient and eye symptoms and between total bacteria and both cough and blocked nose.