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Hay fever: How to cope with a 'pollen bomb' during a heatwave

Hay fever: How to cope with a 'pollen bomb'

With the warmer weather, the tempting smell of barbecues is floating through our windows - but that’s not the only thing in the air. Levels of pollen are always higher in the warmer months - and when we have periods of hot and dry days we may get what is called a pollen bomb.

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What is a pollen bomb?

A pollen bomb happens when trees and plants release millions of grains of pollen within a short period of time as a result of prolonged dry weather. Although pollen bomb isn’t an official phrase used by meteorologists, it is used to describe very high levels of pollen in the atmosphere that can worsen symptoms for those with hay fever.

The weather is known to affect pollen levels. When it is dry and hot with little wind, pollen isn’t dispersed as easily, so the levels remain high and cause irritation to the eyes, nose and throat. Wet weather will temporarily suppress the release of pollen and cause the levels to drop.

High pollen levels happen when there are 50 to 150 grass pollen grains in each cubic metre of air. However, people who are more sensitive to pollen may struggle with hay fever symptoms when the levels are lower.

According to the Met Office, levels of pollen peak during the early morning and late evening. The grass pollen season runs from the end of May to early August, and this affects 95% of hay fever sufferers across the UK.

Where you live can affect the severity of your symptoms too. A study published by researchers at the University of Manchester found people living in urban areas report significantly worse hay fever symptoms1.

Professor Sheena Cruickshank, an immunologist and one of the study authors, said: “This study provides evidence that urban surroundings may exacerbate hay fever and asthma symptoms. These differences in allergy symptoms may be due to variation in the levels of pollutants, pollen counts and seasonality across land-use types.”

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If you’re struggling with hay fever, there are several steps you can take to help ease your symptoms.

When it’s hot, it is tempting to throw open the windows for a cooling breeze. However, it can be better to keep windows and doors shut as much as possible to prevent pollen from coming into your home. Plug-in fans can be a safer way to keep cool if you have hay fever.

Putting Vaseline around your nostrils can help stop pollen from going up your nose and causing irritation. Sunglasses, especially the kind that wrap around your head, can help prevent pollen from getting into your eyes.

After you’ve been outside, shower and change your clothes as they may be contaminated with pollen. Pets can also bring pollen inside too, so it can help to vacuum regularly.

Vacuums with a high-efficiency particulate air (HEPA) filter are more efficient in picking up pollen and dust. Air purifiers, and dusting surfaces using a damp cloth, can help clear pollen from inside your home too.

Medications can help reduce the severity of symptoms. Antihistamines block the action of histamines, chemicals your immune system releases when pollen is around. Some antihistamines may cause drowsiness. Nasal sprays and gels, as well as eye drops like sodium cromoglycate, can also provide relief for symptoms such as itchy noses and eyes. You can buy these medicines from pharmacies.

Keeping checking on the weather can help too, so you can prepare for higher pollen levels. The Met Office, is a good way to check the levels in your area, which may tell you whether your hay fever symptoms are likely to flare up.

  1. Gledson et al: A comparison of experience sampled hay fever symptom severity across rural and urban areas of the UK.

Need hayfever medication?
Complete a simple online consultation through Patient.info, available 24/7
All consultations are reviewed by UK registered clinicians, powered by Evaro - a UK regulated healthcare service supporting over 2 million patients. Treatments can often be delivered next day.

Frequently asked questions

What specifically causes a pollen bomb to happen?

A pollen bomb occurs when there has been a period of prolonged dry weather, which leads to trees and plants releasing millions of pollen grains all at once. This results in very high levels of pollen in the atmosphere, making hay fever symptoms worse.

How can weather conditions other than dry periods affect pollen levels?

The weather plays a significant role in pollen levels. While dry and hot conditions with little wind keep pollen levels high because it isn't dispersed easily, wet weather has the opposite effect. Rain temporarily suppresses pollen release and causes levels to drop.

Are pollen bombs an official scientific term?

No, 'pollen bomb' is not an official term used by meteorologists or scientists. It is a phrase used to describe periods of extremely high pollen levels in the atmosphere.

At what point are pollen levels considered high enough to be a concern for hay fever sufferers?

High pollen levels are generally considered to be present when there are 50 to 150 grass pollen grains in each cubic metre of air. However, individuals who are particularly sensitive to pollen might experience hay fever symptoms even when levels are lower than this.

How does living in a city affect hay fever compared to rural areas?

Research has shown that people living in urban areas tend to report more severe hay fever symptoms compared to those in rural areas. This difference in allergy symptoms might be due to variations in the levels of pollutants, pollen counts, and seasonal changes across different types of land use, such as urban versus rural environments.

Besides medication, what else can I do to reduce pollen exposure inside my home?

To reduce pollen inside, avoid opening windows and doors, especially when it's hot, and use plug-in fans instead. After being outside, shower and change your clothes. Regularly vacuum your home, particularly if you have pets, using a vacuum with a HEPA filter if possible. Additionally, air purifiers and dusting surfaces with a damp cloth can help clear pollen.

Are there common side effects to hay fever medications like antihistamines?

Antihistamines work by blocking chemicals released by your immune system when pollen is present, which helps reduce symptoms. However, some antihistamines can cause drowsiness.

Where can I find information about current pollen levels in my local area?

You can check pollen levels in your area through the Met Office. This can help you prepare for days when pollen levels are likely to be high and your hay fever symptoms might flare up.

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About the authorView full bio

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Lydia Smith

Feature writer

BA, MA, MSc

Lydia Smith is an award-winning journalist and feature writer who has written extensively on women's health and mental health. She is currently studying for an MSc in psychology.

About the reviewerView full bio

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Dr Krishna Vakharia, MRCGP

Chief Medical Officer for Health, Optum UK

MBChB, MRCGP(2013), BMedSci (hons), DFSRH, DRCOG, PGDipDerm (Distn)

Dr Krishna Vakharia is an NHS GP. She is also a regular examiner for the postgraduate Diploma in Practical Dermatology at Cardiff University as well as being the Chief Medical Officer for health at Optum UK.

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