Warning of Severe Pollen Levels by University Forecasters

Dr Beverley Adams-Groom
The University of Worcester’s Senior Pollen Forecaster, Dr Beverley Adams-Groom, with pollen measuring equipment

This is bad news for the 25 per cent of hay fever sufferers allergic to birch pollen (the birch pollen season gets underway this month and ends by mid-May).

Dr Beverley Adams-Groom, senior pollen forecaster at the University of Worcester said: “This season has the potential to be severe for birch pollen in much of the UK, due to a combination of factors. Firstly, higher than average temperatures last June, when the pollen is produced, allowed greater potential for high pollen levels. Secondly, birch trees have a biennial pattern of pollen production, one mild year and one severe year, and this year was already expected to be a high year.”

The University of Worcester has been producing pollen forecasts for the Country since 1995 in conjunction with the Met Office.

Dr Adams-Groom continued: “Summers are often getting warmer, allowing increasing pollen production. We have already seen the hazel and alder tree pollen allergens, which flower in late winter, produce and emit particularly high amounts of pollen this year.

“The only limiting factor could be if we have a particularly wet April, which might limit pollen dispersal, but assuming we have a normal level of rainfall in April the result will be a severe season, certainly the severest we have had in recent years.”

She advised people to keep an eye on the pollen forecasts and pollen calendars available at the University of Worcester website. It is recommended that hay fever sufferers start their treatment in advance of the season.

“In a severe year with very high pollen levels, such as we are likely to see this birch pollen season, there are three effects,” she added. “Firstly, hay fever sufferers are likely to suffer on more days during the season; secondly, people who are less sensitized are more likely to get symptoms and, thirdly, sufferers are more likely to find breakthrough symptoms as their medication cannot deal with all the pollen. In that case, additional treatments may be required and sufferers are advised to seek advice from a pharmacist.”

Dr Adams-Groom said it was too early to predict this year’s grass pollen season, which is influenced by the weather of the preceding months. Grass pollen affects around 95 per cent of hay fever sufferers and the main season usually begins in late May or early June. However, this year, there is likely to be some early-season grasses in flower from mid-April onwards, which will affect some hay fever sufferers but not all, said Dr Adams-Groom.

Recent research led by the University found that climate change was having an impact on the UK pollen seasons. In the case of birch pollen, it found that increasingly warmer weather in June was causing birch trees to produce more pollen and the season was getting more severe across the country.

The study published last year, involving partners from five other institutions, found that climate change was affecting different types of pollen in different ways, both positively and negatively, with some starting earlier in the season and others becoming more severe. Researchers examined data between 1995 and 2020, for key pollen types – grass, birch and oak. They looked at whether there had been significant changes in the patterns of these pollen seasons – such as onset, severity and duration. They analysed variations in weather to see if there were changes in the patterns that could be attributed to climate change.

Read the full study, published in the Science of The Total Environment journal.