What’s the Best Time of Day to Avoid Summer Allergies?
Scientists map the worst times of day for people allergic to grass pollen. Based on their results, the researchers provide new advice to allergy sufferers
Atishoo! Help, there are flowering grasses around, please stay indoors – while your friends enjoy the nice summer weather! Traditionally, people allergic to grass pollen are advised to be aware of high pollen concentrations during the day, and to reduce their outdoor activities during this period.
A new study led by researchers from Aarhus University shows that it is considerably more complicated to avoid grass pollen. Based on a three-year study with intensive measurements at three different locations in Aarhus, they divide the grass pollen season into three periods, as shown in the graph below: a twin peak profile during the early season, a single evening profile in the middle season and a single midday profile during the late season.
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How should people react to these complicated patterns? Dr. Robert Peel, Aarhus University, explains:
“People should avoid being outdoors during the peak hours in periods one and two, especially between 16 and 20. Later in the summer, allergy sufferers should avoid being outdoor in the middle of the day.”
Different species have different patterns
Concentrations of grass pollen are influenced by many factors, the most important being the weather and the emissions, which again depends on the grass species. In Denmark alone, 230 species of grass (atishoo!) have been recorded, of which around 20 species are likely to be particularly common in urban environments.
Even though the information of the exact species present in the monitored area and pollen release patterns of the individual species are far from complete, Peel and his colleagues conclude that the best way to explain the three concentration patterns is to look at the succession of different grass species with different diurnal flowering patterns which dominate the atmospheric pollen loads as the season progresses.
The study was performed in collaboration with colleagues from the universities of Worcester, Vienna, Roskilde and the Astma-Allergy Association Denmark. Seasonal variation in diurnal atmospheric grass pollen concentration profiles. R.G. Peel et al., Biogeosciences 11 (2014), 821-832. Doi:10.5194/bg-11-821/2014, http://www.biogeosciences.net/11/821/2014/bg-11-821-2014-metrics.ht