Temporal Variation of Indoor Ultra-Fine Particles during Working-Hours in an Occupied Office in Changsha

摘要

Few studies have examined the temporal variation of UFP levels in office environments. The aim of this study is to monitor UFP concentrations during working-hours in an occupied office with attention to factors that may influence their number concentration. This study was carried out in a 400-square-metre office with eighty white-collar workers. During the four-week period, the office was ventilated with a one-pass air handing system which includes a pre-filter and a high efficiency particulate air filter in the first two weeks and includes an electrostatic precipitator in addition in the following two weeks. Indoor/outdoor ozone and indoor UFP concentrations were monitored with online apparatuses on workdays and air change rate of the office was measured as well. Results show that two or three bursts could be observed during the temporal variation of indoor UFPs in most workdays. It indicates that both occupant density and ozone levels influence the formation of UFPs in this office environment. And the UFP levels are strongly related to outdoor ozone concentration and occupant density.