Research team quantifies changes in pollen counts and pinpoints geographic variations
By Summit Voice
SUMMIT COUNTY — Many climate change models have predicted increases in pollen levels and associated allergies, as rising carbon dioxide levels and warmer temperatures spur plant growth.
Advances by invasive species are another factor that could lengthen the pollen and allergy season, according to a research team that is starting to quantify the changes across Europe, where pollen counts have gone up from Reykjavik to Thessaloniki.
The biggest changes thus far have been in urban areas, where pollen counts are increasing at the rate of about 3 percent each year, according to Prof. Annette Menzel from the Technische Universität Muenchen. In rural areas, the rate of increase is about 1 percent per year, but the researchers believe climate change will strengthen the trend.
When trees and plants release their pollen, millions of hay fever sufferers are affected by sneezing fits and itchy, watery eyes. Today in Germany, roughly every fourth person suffers from allergies – and this figure is set to rise.
“The conditions we are recording in urban environments today are expected to spread to rural areas in the future,” said ecoclimatologist Prof. Annette Menzel
The scientists evaluated 1,221 long-term pollen series from thirteen different countries, calculating normalized trends of annual pollen indices over a period of at least ten years. These indices can now be used to compare different key allergenic pollen species from different climates.
“Even today, cities are warmer, dryer and more polluted places,” Menzel said. Temperatures in dense, urban environments, known as heat islands, can be one to three degrees higher than the surrounding areas. Levels of CO2 and pollutants are also often higher in these environments. Ozone values, however, are usually higher in the regions surrounding larger cities.
Pollen, however, is only a carrier of allergens, making pollen count just one factor in the prediction of future allergy trends. Menzel is therefore working with allergy experts to assess allergy trends in urban and rural areas. Their studies have revealed that levels of allergens vary from year to year and that pollen counts also differ in rural and urban areas.
More detailed research results will soon be available. What the scientists do already know, however, is that city dwellers will not be the only ones suffering from future climate trends.