Abstract
IntroductionIt is important to study potential differences in pollen concentrations between sampling heights because of diverse outdoor and indoor activity of humans (exposure) at different height levels in urban environments. Previous studies have investigated the effect of height on pollen concentrations based on just one or a few sampling points. We studied the effect of sampling height on grass pollen concentrations in several urban environments with different levels of urbanity.MethodsThis study was conducted in the Helsinki Metropolitan Area, Finland, in 2013 during the pollen season of grasses. Pollen grains were monitored in eight different points in the morning and afternoon. Rotorod-type samplers were attached on sampling poles at the heights of 1.5 meters and 4 meters.ResultsGrass pollen concentrations were on average higher at the height of 1.5 meters (Helsinki mean 5.24 grains / m3; Espoo mean 75.71 grains / m3) compared to the height of 4 meters (Helsinki mean 3.84 grains / m3; Espoo mean 37.42 grains / m3) with a difference of 1.40 grains / m3 (95% CI -0.21 to 3.01) in Helsinki, and 38.29 grains / m3 (7.52 to 69.07) in Espoo, although not always statistically significant. This was detected both in the morning and in the afternoon. However, in the most urban sites the levels were lower at 1.5 meters compared to 4 meters, whereas in the least urban sites the concentrations were higher at 1.5 meters. In linear regression models with interaction terms, the modifying effect of urbanity on concentration-height relation was statistically significant in both cities. The effect of urbanity on pollen concentrations at both heights was stronger in less urban Espoo.ConclusionsThe present study provides evidence that height affects the abundance and distribution of grass pollen in urban environments, but this effect depends on the level of urbanity.
Highlights
It is important to study potential differences in pollen concentrations between sampling heights because of diverse outdoor and indoor activity of humans at different height levels in urban environments
Grass pollen concentrations were on average higher at the height of 1.5 meters (Helsinki mean 5.24 grains / m3; Espoo mean 75.71 grains / m3) compared to the height of 4 meters (Helsinki mean 3.84 grains / m3; Espoo mean 37.42 grains / m3) with a difference of 1.40 grains / m3 in Helsinki, and 38.29 grains / m3 (7.52 to 69.07) in Espoo, not always statistically significant
The present study provides evidence that height affects the abundance and distribution of grass pollen in urban environments, but this effect depends on the level of urbanity
Summary
It is important to study potential differences in pollen concentrations between sampling heights because of diverse outdoor and indoor activity of humans (exposure) at different height levels in urban environments. Subjects suffering from pollen allergy can try to reduce their exposure to pollen grains by spending more time indoors or outdoors in environments where pollen concentration are known to be low. Such environments include indoor spaces with efficient filter system [3] and outdoor spaces that are surrounded by a limited number of vegetation, e.g. the most urban environments [4]. Rojo et al [13] have estimated the near-ground vertical profile of pollen concentrations based on data from 25 areas and 59 pollen stations They found that pollen concentrations decreased with height and daily fluctuations in pollen concentrations were stronger at near-ground level (< 10 m above ground) compared to higher levels. Other factors that have been suggested to affect the distribution and dispersion of pollen grains include the location and height of flowers, the period of pollination, the number and characteristics of pollen grains released, and the habitat and meteorological conditions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
