Climate Change and Allergies

With the world’s climate changing because of global warming, our natural world is evolving and adapting, and some of these naturally occurring changes and adaptations are directly contributing to an increase in the incidence of many common allergens. Furthermore, actions and practices introduced to combat this onslaught of global climate change, and its impact are also creating man-made conditions which allow certain allergens to thrive.

This evolving world – caused by climate change – is important to understand as it may directly affect how people may need to manage their allergies on a day-to-day basis.

Respiratory allergies affected by climate change

Hay Fever

Climate change has brought on many new challenges for our environment including extreme weather patterns. This is having an effect on our plant life and is contributing to the creation of extended pollen seasons with global warming. This means you may suffer symptoms for longer, so will have to take medication, or practice avoidance and reduction measures for a longer period of time than in previous years.

Furthermore, the pollution created by modern living practices and contributing to climate change, is also causing pollen particles to mutate and evolve. There is evidence that pollutant particles are coating the pollen grains making them both irritant and allergenic

Research has shown that pollen is becoming increasingly stronger and stickier to survive in more polluted environments, resulting in more severe expressions of symptoms in individuals with allergic rhinitis (the medical name for symptoms of hay fever) because the pollen is more potent.

To try and mitigate the effects of pollution, there has been a drive to plant more trees.  Unfortunately, not much thought has been given into the types of trees being planted. One of the favourite species of trees for planting is birch trees because of its fast-growing properties. However, this species is highly allergenic with rates of birch pollen allergy continuing to rise and due to the pollen loads, symptoms are becoming more severe. In the UK, we are one of the worst affected countries in the world for hay fever and asthma.

Worryingly, weather patterns caused by our changing climate, such as more frequent extreme weather and thunderstorms, also have an impact on allergies.  Thunderstorm asthma is a rare event that can trigger an asthma attack for people with allergies. is due to high winds drawing higher levels of pollens and pollution particles into the air. The pollen breaks down into smaller particles that when breathed in, can get deeper into the smaller airways of the lungs and trigger asthma symptoms. Hay fever can cause asthma symptoms to worsen, and these weather conditions can cause even mild symptoms to become severe (such as difficulty breathing and chest tightening).

House dust mite allergy

Populations of developed countries are spending 90% of their time in the indoor environment. This is more than ever before and gives greater exposure, for a longer period, to indoor allergens.  Concurrently, energy conservation measures have also been introduced to arrest the pace of climate change in most day-to-day practices, and especially within the housebuilding sector. This means that new homes are being built with energy ratings in mind, to ensure less heat escapes and therefore energy use is reduced. This has resulted in houses that are now so sealed to keep in warmth with less ventilation circulating around the home. This can increase both the temperature and humidity of the indoor environment, creating perfect conditions for house dust mites to thrive and therefore generating a heavier burden of the allergen within the home environment.

House dust mite allergies can trigger allergic rhinitis (hay fever) symptoms all year round, but these are especially pronounced in those months when outdoor living is especially restricted, such is the winter months. As the weather gets colder we turn up the heating, often drying washing indoors and along with cooking, showering etc this all raises the indoor temperature and puts more water vapour into the air, raising the humidity of the indoor environment. These are perfect conditions for house dust mites. Like hay fever, when not controlled, house dust mite allergy may lead to asthma which is both debilitating and carries a risk of hospitalisation in the event of a serious asthma attack.

Mould allergy

The same indoor conditions, such as inadequate ventilation, an overly warm and humid indoor environment can also give rise to the perfect environment for indoor moulds to thrive. It is important to note that there are mould/fungi present in every house. This can be in carpets, wallpaper, mould on windows, walls, fridges, bathrooms etc. However, constant exposure to high levels of mould can increase the probability of the development of allergy. With energy conservation being a target, the drive to ‘seal’ houses has led to our houses being warmer and if windows are not often opened then the humidity can rise due to the types of activities we may do in the home, such as drying washing, cooking, showering etc. , climate change induced heavier rains and floods can bring damp and high levels of relative humidity, (typically above 70–80%), which provide mould-favourable conditions. (ref: International Journal of Environmental Research and Public Health 2019)

Exposure to indoor mould contamination has been associated with an increased risk of developing and/or exacerbating a range of allergic and non-allergic diseases.  Exposure to indoor dampness and fungal contamination has been associated with a 30% to 50% increased risk of asthma. Mould can be responsible for severe asthma.

Overall, this rise in exposure to indoor allergens presents a significant public health risk.  There is much evidence on the role of indoor damp in asthma affecting children, Also, there is evidence that exposure to indoor mould contamination in social housing increases the risk of asthma, which appears to be greatest among older adults and women. These are often the most vulnerable in our society and we need to do what we can to protect them. This is all very worrying and using approaches to reduce risks of developing allergy to mould is so important as is treatment and management of symptoms once allergy has been established.

Food allergies affected by climate change

The increase in air pollution from fossil fuels and animals, as well as finding sustainable food sources has led to recommendations to reduce the amounts of animal protein we eat and move towards more plant-based diets.  This has meant that some foods have vast amounts of the same plant protein i.e. pea protein, and we are now starting to see an increase in reports of people developing allergic reactions to these ingredients.  For example, vegan products may contain 60-70% protein compared with 8% protein by weight in an average serving of peas. Meanwhile, emerging food allergens causing reactions include legumes such as chickpeas and lentils.

In the UK we are also seeing increased rates of pollen food syndrome (PFS) in both adults and children. This is where a person develops an allergy to a pollen such as grass or birch tree which can result in a cross reaction with certain foods which have a very similar structure.  The body’s immune system can then mistake these foods for the pollen and reacts to it. This called a cross-reacting allergen. Usually, the symptoms are mild and just localised to the mouth and throat and is usually caused by eating a food in its raw form. However, there are some people who have a very specific problem which causes them to react to a part of the protein called lipid transfer protein.  This is a complex food allergy associated with more severe types of reactions for which the risks need to be assessed by a specialist.

Managing your allergies in changing climates

Hay fever

The key to managing symptoms in climate change is knowing what pollens trigger your hay fever and tracking pollen counts.

Most people can use a pollen calendar to track when symptoms are most severe which can then help identify the pollen to which they are most allergic. In severe cases, it is also possible to be tested. This is a very important step when considering advanced treatments such as immunotherapy for people who are having difficulty in getting their symptoms under control. Other tips for managing hay fever symptoms which are exacerbated by climate change include:

• Starting treatments at least two weeks before symptoms begin for optimal effectiveness. Tools such as a pollen calendar and pollen forecasts can help you prepare and start taking your medication at the right time.
• Practicing pollen avoidance measures such as
  • Keeping windows closed when indoors – this is most important in the early mornings and in the evening
  • Showering and washing your hair after arriving home and change your clothing
  • Avoiding the use of an external clothesline to dry laundry when pollen counts are high
  • Wearing wraparound sunglasses when outdoors to keep pollen allergens out of your eyes. A hat with a peak or large brim can also help keep pollens from your eyes and face.
  • Read our Hay Fever and Allergy Rhinitis factsheet for more information on managing hay fever symptoms
• Regularly check the media for news around hay fever, as this is a common topic they cover during the hay fever season. In particular, media will report on Met Office warnings of pollen bombs. This is a term used to describe days when pollen forecasts are predicted to rocket, usually due to extreme weather patterns involving heat and wind – the perfect conditions for pollens to disperse. On these days it is especially important during these events to plan ahead and avoid any long periods of time outside.

House dust mite and mould allergies

It is important to keep your home well-ventilated because mould and house dust mite thrive in warm humid conditions. However, if you also live with hay fever, opening windows may not be possible and instead air purifiers may be used instead to help to reduce allergens in the indoor environment.

Other ways to reduce exposure include:

• Knowing where to find indoor allergens around the home and maintaining a thorough cleaning regime. Visit our Allergy House to identify allergen hot spots around the home.
• If possible, invest in some allergen reducing cleaning equipment and products, such as sanitising steam cleaners and HEPA filter vacuum cleaners. Allergy UK’s Seal of Approval is a great way to identify products which have been tested and proven to reduce or remove allergens from the atmosphere.
• During the winter months, avoid over warming your home to prevent the build-up of humidity. Turn off central heating at night and open windows in the morning to freshen up your home without losing too much heat. This can also reduce your energy usage considerably, saving you money and helping the environment.
• Spending more time outside during the winter is important to give your system a break from exposure to indoor allergens and is great for your mental health during the shorter days.
• If possible, use a smart meter app to prevent your home being kept warm all day long when you are out. Most apps have eco functions and settings that automatically turn heating off when no one is home and the option to manually turn it on/off when you are away from the home.

Our house dust mite factsheet and mould factsheet contains lots more in-depth information on reducing exposure and treatments for these allergens.

What you can do

Climate change is not just today’s problem, it will go on to affect the health of our families for generations to come. The impact it is already having on respiratory allergies is already being seen, but we can act to reduce the speed at which climate change can have an impact on allergies.

Supporting Clean Air Initiatives: Clean Air Day

Clean Air Day stands as the UK’s largest air pollution campaign, rallying individuals and communities to take action against air pollution. One impactful way to get involved is by writing to your local councillor. Councillors have the authority to implement measures that can significantly improve air quality, and by expressing support for such measures, we can encourage them to take decisive action.

Visit the Clean Air Hub (https://www.cleanairhub.org.uk/take-action) for a template and step-by-step guidance on how to reach out to all your councillors effectively.

Live more sustainably

Taking steps to live more sustainably, no matter how small they may seem, will help minimise your own contribution to the climate change crisis. Can you take on these five ways to live more sustainably?

1. Recycle: More than 50% of waste ends up in landfill or incinerators, releasing greenhouse gasses into the environment. Recycling general and medical items, such as asthma inhalers and adrenaline auto-injectors, can reduce this waste. Consider donating clothes, toys, furniture, etc. to charity or sell on through pre-loved websites/apps.
2. Buy less: The growing demand for consumables is driving the demand for materials higher, such as oil, metals and water. Instead, think twice before buying; do you need it, will you keep it, do you love it? Buying second-hand items will also help reduce this demand.
3. Food shop with consideration: Grocery shopping creates a lot of single use plastic and food waste. Our supermarket aisles are also lined with foods and produce imported from all over the world which contributes to carbon footprints. Buying less, more often will reduce food waste as fresh items will be used and not spoil. Also consider buying local and seasonal produce from fruit and veg stalls, butchers and the UK grown options in the supermarket. Where possible, avoid food items unnecessarily wrapped in single use plastics and bring your own bags.
4. Eat less meat and dairy: The farming of animals is one of the biggest contributors to climate change. Can you introduce a meat-free and dairy-free day to your meal plans? Choosing sustainably farmed meat and dairy, can also help reduce its impact.
5. Drive less: Transport is responsible for 23% of global emissions, impacting climate change. Consider if alternative methods could be taken to get to your destination, such as a car share, walking, cycling or public transport to help reduce these emissions and air pollution.

These are just a handful of small ways that you can influence a big change – in the words of Anne Marie Bonneau…

“We don’t need a handful of people taking perfect action, we need millions of people taking imperfect action every single day.”

For more inspiration Friends of the Earth are experts in this area and have some more great tips on living a more sustainable life.

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