Longer allergy season, pollen travels further

THURSDAY February 25, 2021 (HealthDay News) – If you suffer from itching, sneezing and wheezing seasonal allergies, you are probably painfully aware that pollen the season starts earlier and lasts longer than ever.

It’s a result of climate change, and new research in Germany offers an explanation for this prolonged sneezing season: The pollen is on the move, with early-flowering spores now floating in traditional places and in regions where these pollen species usually bloomed later, if at all.

“In the long term – with climate change and the distribution of species changing – we have to take into account the ‘new’ species of pollen that are more frequently carried to us,” said study author Ye Yuan from the University. Munich technique. He holds a chair in ecoclimatology.

“The transport of pollen has important implications for the length, timing and severity of the allergenic pollen season,” Yuan said.

The pollen has the ability to travel hundreds of kilometers from its original flowering location, Yuan and his colleagues pointed out. To find out how common pollen transport is, they performed two analyzes.

The first analysis of information collected between 1987 and 2017 at six atmospheric data collection stations across the German state of Bavaria. The aim was to measure changes at the start of the flowering and pollen seasons.

This study found that certain pollen species – such as those of hazelnut shrubs and / or alders – produced up to two days earlier each year. Birches and ash trees began shedding their pollen half a day earlier, on average.

This matches what scientists already know about one of the most obvious impacts of climate change: As temperatures rise, flowers tend to bloom earlier.

Warmer temperatures also cause carbon dioxide levels to increase, which in turn stimulates pollen production.

Such momentum has extended the pollen season by 20 days over the past three decades, Yuan’s team noted.

Similar observations were published earlier this month in the journal Proceedings of the National Academy of Sciences.

The study, conducted by the University of Utah, found that pollen levels in the United States and Canada had jumped 21% since 1990 and the length of the pollen season had increased by three weeks.

A second analysis by Yuan’s team looked at data collected at three pollen stations in Bavaria between 2005 and 2015 to identify modes of pollen transport.

All pollen species found before local flowering began were believed to have come from afar, although researchers did not calculate the distance traveled by a particular species. Species not considered native to the region were also characterized as transported pollen.

Almost two-thirds of the pollen collected was ultimately found to be non-native. The researchers concluded that the transport of pollen before the season was quite common.

Although the study focused only on regions in Germany, Yuan said similar results would likely be seen around the world.

He added that it is “very likely” that the pollen trends observed by his team will continue “as climate change, including rising temperature and rising CO2 levels, systematically contribute to the pollen season. and the transport of pollen “.

The research was published on February 25 in the journal Allergy frontiers.

Plant physiologist Lewis Ziska, of Irving Medical Center at Columbia University in New York City, reviewed the results and said they added “a new and interesting dimension” to how climate change could affect the pollen season.

“As the climate changes [and] As weather conditions become more extreme, additional preseason pollen can become a very important aspect of pollen exposure and health consequences, ”Ziska said. We will have to explore how similar events might affect pollen exposure in the United States. “

More information

Learn more about climate change and allergies to American Asthma and Allergy Foundation.

SOURCES: Ye Yuan, MSc, professor, ecoclimatology, Technical University of Munich, Freising, Germany; Lewis Ziska, PhD, plant physiologist and associate professor, environmental health sciences, Columbia University Irving Medical Center, New York City; Allergy frontiers, February 25, 2021