Indoor birch pollen concentrations differ with ventilationrnscheme, room location, and meteorological factors

摘要

Indoor pollen concentrations are an underestimated human health issue. In this study,rnwe measured hourly indoor birch pollen concentrations on 8 days in April 2015 withrnportable pollen traps in five rooms of a university building at Freising, Germany. Theserndata were compared to the respective outdoor values right in front of the rooms andrnto background pollen data. The rooms were characterized by different aspects andrnwindow ventilation schemes. Meteorological data were equally measured directly inrnfront of the windows. Outdoor concentration could be partly explained with phenologicalrndata of 56 birches in the surrounding showing concurrent high numbers ofrntrees attaining flowering stages. Indoor pollen concentrations were lower than outdoorrnconcentrations: mean indoor/outdoor (I/O) ratio was highest in a room with fullyrnopened window and additional mechanical ventilation (.75), followed by rooms withrnfully opened windows (.35, .12) and lowest in neighboring rooms with tilted windowrn(.19) or windows only opened for short ventilation (.07). Hourly I/O ratios dependedrnon meteorology and increased with outside temperature and wind speed oriented perpendicularrnto the window opening. Indoor concentrations additionally depended onrnthe previously measured concentrations, indicating accumulation of pollen inside thernrooms even after the full flowering period.