ABSTRACT
ABSTRACT: The objective of the study was to measure the mass concentrations of aerosol particles in classrooms and to determine their associations with number and activities of present students, indoor thermal conditions (temperature, relative humidity), CO2 concentration and season of the year. Monitoring took place in 6 classrooms in 3 schools when the classrooms were occupied and they were vacant during the heating and summer seasons. Particle Mass (PM) concentrations were measured by laser photometer. The average PM concentrations ranged from 185 to 363 µg/m3
and from 132 to 305 µg/m3 in the heating and summer season, respectively. The highest ratio of PM concentrations in occupied and vacant classrooms (O/V) was for coarse particle fractions. Due to the fact that measurements were carried out in real field conditions, highly significant correlations between the PM concentration and the number of students present were not found. Higher coarse particle fraction concentrations were observed at higher indoor air temperatures and CO2 concentrations. Concentrations of small particle fractions were positively correlated with indoor air relative humidity.
