Spring Allergies Are Hard To Avoid
May 28, 2014

What Is The Worst Time Of Day For Spring Allergy Season Sufferers?

April Flowers for redOrbit.com - Your Universe Online

During the spring and summer, flowering grasses turn the world into a beautiful vision of green. These same grasses also turn allergy sufferers into hermits, hiding in their houses from pollen. Doctors and other clinicians have traditionally advised allergy sufferers to be aware of the pollen concentrations during the day and to reduce their outdoor activities during this season.

But is it really that easy to avoid grass pollen? A new study from Aarhus University in Denmark reveals that avoiding grass pollen is considerably more complicated than previously thought.

The findings, published in Biogeosciences, are based on a three-year study that involved intensive measurements at three separate sites in Aarhus. These measurements allowed the international team of scientists to divide the grass pollen season into three distinct periods: 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.

Dr. Robert Peel, Aarhus Department of Environmental Science professor, explains how allergy sufferers should react to this information: "People should avoid being outdoors during the peak hours in periods one and two, especially between 16 [4pm] and 20 [8pm]. Later in the summer, allergy sufferers should avoid being outdoors in the middle of the day."

The research team also found that grass pollen concentrations are influenced by many factors. Perhaps the most important of these factors is weather and pollen emissions, which depend upon the species of grass. For example, in Denmark there are 230 known species of grass. Twenty of these species are common in urban environments. Each species' emissions are driven by different weather parameters; for example, the temperature of the current or previous day, or if it is currently raining or not raining. Each species has an intensive flowering period of about one to two weeks, but the total season lasts approximately two months. All of this adds to the complexity of grass pollen predictions. For the most part, people react to all grass pollens the same way, and it is impossible to distinguish the species when counting pollen under a microscope.

Peel and his colleagues admit that understanding the exact species present in their monitored areas, and the pollen release patterns of those species, is far from complete. They hope to complete their understanding of the three concentration patterns by looking at the succession of different grass species with different diurnal flowering patterns which dominate the atmospheric pollen loads as the season progresses.