Risk of exposure to airborne <i>Ambrosia</i> pollen from local and distant sources in Europe – an example from Denmark

Abstract

Background. Ambrosia artemisiifolia L. is a noxious invasive alien species in Europe. It is an important aeroallergen and millions of people are exposed to its pollen. Objective. The main aim of this study is to show that atmospheric concentrations of Ambrosia pollen recorded in Denmark can be derived from local or more distant sources. Methods. This was achieved by using a combination of pollen measurements, air mass trajectory calculations using the HYPLIT model and mapping all known Ambrosia locations in Denmark and relating them to land cover types. Results. The annual pollen index recorded in Copenhagen during a 15-year period varied from a few pollen grains to more than 100. Since 2005, small quantities of Ambrosia pollen has been observed in the air every year. We have demonstrated, through a combination of Lagrangian back-trajectory calculations and atmospheric pollen measurements, that pollen arrived in Denmark via long-distance transport from centres of Ambrosia infection, such as the Pannonian Plain and Ukraine. Combining observations with results from a local scale dispersion model show that it is possible that Ambrosia pollen could be derived from local sources identified within Denmark. Conclusions. The high allergenic capacity of Ambrosia pollen means that only small amounts of pollen are relevant for allergy sufferers, and just a few plants will be sufficient to produce enough pollen to affect pollen allergy sufferers within a short distance from the source. It is necessary to adopt control measures to restrict Ambrosia numbers. Recommendations for the removal of all Ambrosia plants can effectively reduce the amount of local pollen, as long as the population of Ambrosia plants is small.

Spatial and temporal variations in airborne Ambrosia pollen in Europe

“…2a). This probably reflects the intermittent nature of atmospheric transport episodes from areas with notable sources of Ambrosia pollen to areas where the plant is less common, or not found at all (Stach et al 2007; Smith et al 2008; Sikoparija et al 2009; Kasprzyk et al 2011; Šikoparija et al 2013; Sommer et al 2015). The results show that Ambrosia pollen is also frequently recorded in the Balkans, Greece, Turkey and Georgia.…”

The long distance transport of airborne Ambrosia pollen to the UK and the Netherlands from Central and south Europe

“…These diurnal patterns suggested that the pollen grains did not originate from local sources, since studies have shown that Ambrosia pollen from local plants is usually recorded in the air from about 6.30 am to around midday (Ogden et al 1969). Furthermore, the geographical scope of the episode, recorded in both Leicester and Leiden, suggests that this was not a localized phenomenon caused by emission from local populations (Sommer et al 2015). …”

“…Current practice is therefore to use 3D trajectories, most commonly in relation to Ambrosia by using the HYSPLIT model (e.g. Makra et al (2010); Saulienė et al (2011); Zemmer et al (2012) and recently Sommer et al (2015)). Spatial and temporal resolution in the input data is, however, also very important as demonstrated by Skjøth et al (2002) and Hernandez-Ceballos et al (2014).…”

Birch pollen allergy in Europe

“…These atmospheric allergens may induce allergic rhinitis symptoms, but more research is needed to confirm this hypothesis. Furthermore, there has been documentation of ragweed pollen being transported by thunderstorms or wind currents hundreds or even thousands of kilometers into nonendemic areas, resulting in clinically relevant pollen levels . Modeling of birch pollen transport in Finland indicated the pollen sources included Baltic States, Russia, Germany, Poland, and Sweden .…”