Indoor-Outdoor Atmospheric Particulate Matter Relationships in Naturally Ventilated Offices

Abstract

Atmospheric particle size distribution and number concentrations were investigated in three naturally ventilated offices and outdoors. The offices were located in a University suburban campus in newly constructed, one-storey buildings. Measurements were conducted with a laser optical particle counter. Synoptic meteorological data, for the duration of the experiment, were obtained from the NOAA satellite data archive. The indoor to outdoor averaged number concentration ratios in the offices during working hours were in the range of 0.35-14.68. Construction activities in the vicinity of one office had a pronounced effect on the indoor number concentrations of particulate matter (PM). Indoor sources were traced to the movement of people, computer operation and environmental tobacco smoke. Re-suspension, appears to contribute to the number concentrations of PM, over all size ranges. Meteorological conditions with respect to office orientation also had a significant impact on indoor PM number concentrations.