Investigation of personal air pollution exposures and occupants’ fresh air demands in two office buildings in Switzerland

Abstract

Abstract This study assessed personal exposures to indoor air pollutants in office environments with dynamic occupancy profiles. A two-week field campaign was conducted in two Swiss office buildings, examining three target areas in each building. We measured air temperature (T), relative humidity (RH), CO2, PM2.5, and PM10 levels at three stationary locations of each target area. Four office workers carried a customized vest to monitor personal CO2 and PM levels near their breathing zone. Using smartwatches, the workers completed hourly surveys about their activity profiles and preferences for outdoor air. We found that CO2 and PM10 concentrations were 1.2–1.3x and 1.8–2.5x higher, respectively, in the personal monitor compared to stationary sensors. Occupants had higher personal CO2 levels during sitting activity and higher personal PM levels during standing activity. Lunch/coffee/call activities were associated with discernible peaks of personal exposure to CO2, PM2.5, and PM10. The higher T coupled with lower RH measured at the personal level was associated with higher occupant demands for outdoor air.