title: Indoor birch pollen concentrations differ with ventilation scheme, room location, and meteorological factors.
abstract: Indoor pollen concentrations are an underestimated human health issue. In this study, we measured hourly indoor birch pollen concentrations on 8 days in April 2015 with portable pollen traps in five rooms of a university building at Freising, Germany. These data were compared to the respective outdoor values right in front of the rooms and to background pollen data. The rooms were characterized by different aspects and window ventilation schemes. Meteorological data were equally measured directly in front of the windows. Outdoor concentration could be partly explained with phenological data of 56 birches in the surrounding showing concurrent high numbers of trees attaining flowering stages. Indoor pollen concentrations were lower than outdoor concentrations: mean indoor/outdoor (I/O) ratio was highest in a room with fully opened window and additional mechanical ventilation (.75), followed by rooms with fully opened windows (.35, .12) and lowest in neighboring rooms with tilted window (.19) or windows only opened for short ventilation (.07). Hourly I/O ratios depended on meteorology and increased with outside temperature and wind speed oriented perpendicular to the window opening. Indoor concentrations additionally depended on the previously measured concentrations, indicating accumulation of pollen inside the rooms even after the full flowering period.
authors.affiliation: Department of Ecology and Ecosystem Management, Ecoclimatology, Technische Universität München, Freising, Germany.|Institute for Advanced Study, Technische Universität München, Garching, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Menzel
authors.affiliation: Department of Ecology and Ecosystem Management, Ecoclimatology, Technische Universität München, Freising, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Matiu
authors.affiliation: Department of Ecology and Ecosystem Management, Ecoclimatology, Technische Universität München, Freising, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Michaelis
authors.affiliation: Physical Geography/Landscape Ecology and Sustainable Ecosystem Development, Catholic University of Eichstätt-Ingolstadt, Eichstätt, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Jochner
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D029662:Betula; D004784:Environmental Monitoring; D005858:Germany; D006801:Humans; D016014:Linear Models; D008685:Meteorological Concepts; D011058:Pollen; D014495:Universities; D014691:Ventilation
chemical_list: D000393:Air Pollutants
keywords: 
  Betula
  ; air temperature; indoor pollen concentration; indoor/outdoor ratio; ventilation; wind speed and direction