Winter Indoor Air Quality and Allergies: Managing Symptoms in Sealed UK Homes

During the winter months, homes often remain closed for longer periods. Reduced ventilation combined with continuous heating can alter indoor air quality. For people living with allergic rhinitis (e.g. hay fever), these environmental changes may influence symptoms such as sneezing, a runny nose, nasal congestion and itchy eyes.

Research suggests that people in the UK spend, on average, around 90% of their time inside buildings, making indoor air quality and the temperature of homes extremely important. When ventilation is limited, airborne particles and pollutants can accumulate, increasing overall exposure throughout the day.

How reduced ventilation can influence allergen levels

Airborne indoor allergens include biological particles such as fungal spores and pollen, as well as proteins present in household dust. These bioaerosols may originate within the home — for example, from damp areas and mould growth — or enter from outdoors through windows and doors.

When air exchange is insufficient, pollutants and allergens are not effectively diluted. This can favour the build-up of suspended particles. Routine activities such as vacuuming or the movement of pets can resuspend settled particles into the air.

Poor ventilation may also allow excess moisture to accumulate, creating conditions that support mould growth.

Common indoor allergens in sealed winter homes

The main household allergens include dust mites, mould spores, shed skin particles and allergenic proteins found in animal saliva and urine.

Dust mites thrive in warm and humid environments and can be found in bedding, carpets and upholstered furniture. Dust mite sensitisation is associated with allergic rhinitis and can contribute to symptoms such as sneezing, a runny nose and watery eyes.

Mould grows in damp areas, such as windows with condensation, walls affected by leaks and spaces with inadequate ventilation. Exposure to mould may irritate the nasal passages and contribute to rhinitis symptoms.

The presence of pets can also influence indoor air quality, as allergenic proteins may remain airborne for extended periods and settle into furniture and dust.

The role of heating in particle circulation

Central heating systems, gas cookers and fireplaces can influence indoor air quality. Heating may circulate and redistribute dust already present in the environment.

In addition to biological allergens, non-protein irritants may affect the airways. These include particulate matter released during cooking, smoke and volatile organic compounds (VOCs) from cleaning products and aerosols. Although these substances are not allergens in the classical sense, they may irritate the nasal passages and eyes and make symptoms more noticeable in sensitive individuals.

Strategies to improve indoor air quality in winter

Maintaining ventilation is one of the most important measures. Opening windows when possible, using extractor fans in kitchens and bathrooms, and ensuring ventilation systems are functioning properly can help reduce moisture and particle build-up

Additional strategies include:

• Reducing sources of dampness to prevent mould growth
• Cleaning surfaces regularly with a damp cloth to avoid resuspending dust
• Washing bedding frequently at 60°C
• Vacuuming with equipment that uses HEPA filters
• Avoiding smoking or vaping indoors
• Minimising the use of sprays and aerosols

It is important to note that the impact of houseplants on indoor air quality varies depending on species, soil type and care. Evidence on the impact of houseplants on indoor air quality in typical homes is mixed, and they should not be relied upon as a primary strategy for reducing indoor pollutants.

Managing allergic rhinitis symptoms indoors

Allergic rhinitis is triggered by exposure to environmental allergens and can cause nasal and eye symptoms. When exposure occurs predominantly indoors, symptoms may appear more persistent during winter.

Histallay may help relieve symptoms such as sneezing, a runny nose, nasal congestion and itchy eyes when they occur in indoor environments. Taking the medicine as directed will support appropriate symptom control.

Recognising patterns — for example, symptoms that worsen after prolonged time indoors — may assist in identifying environmental contributors.

When to seek medical advice

Seek medical advice if symptoms persist despite efforts to improve the indoor environment, significantly affect sleep or daily activities, or become difficult to manage.

Sudden throat swelling, severe difficulty breathing, dizziness or loss of consciousness may indicate a serious allergic reaction such as anaphylaxis and require calling 999 immediately.

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