Air pollution and airborne allergens
Source: gov.uk (2025-08-07)

There is evidence that air pollutants such as ozone, nitrogen dioxide and sulphur dioxide can exacerbate respiratory conditions.

CCHS navigation menu: CCHS homepage (https://www.gov.uk/government/organisations/the-centre-for-climate-health-security)Topic: environmental exposures (https://www.gov.uk/government/collections/environmental-exposures) Air-related exposure: airborne allergens (https://www.gov.uk/government/collections/airborne-allergens)Part of: learning about airborne allergens

Key resources for air pollution and airborne allergens:

Air pollution and airborne allergens

Airborne allergens: A quick guide (https://www.gov.uk/guidance/airborne-allergens-a-quick-guide)

More content:
- HECC chapter 6: Outdoor airborne allergic pollen and fungal spores (https://assets.publishing.service.gov.uk/media/6570509d3831ec0013c7496e/HECC-report-2023-chapter-6-aeroallergens.pdf)
Pollution, airborne allergens and health

Air pollutants such as particulate matter, ozone, nitrogen dioxide and sulphur dioxide can have a variety of effects on health including making respiratory conditions worse (1 (#ref)). These pollutants can cause inflammation of the airways, leading to symptoms like coughing, mucus production, and shortness of breath. Studies have shown associations between nitrogen dioxide exposure and reduced lung development, as well as respiratory infections in early childhood (2 (#ref)).

The combination of air pollution with bioaerosols (airborne particles of biological origin, including bacteria, pollen and manmade particles) can have negative effects on respiratory conditions. For example, diesel particulates have been found to reduce the body’s immune response to airborne germs, and black carbon can increase bacteria’s ability to cause disease (3 (#ref)). Additionally, ozone has been found to combine with pollen allergens (4 (#ref)) to make pollen more potent and has also been found to trigger symptoms of allergic disease at lower pollen concentrations (5 (#ref)). The effects of air pollution on respiratory allergies might depend on several factors, including the pollution’s components and concentrations.

How air pollution can worsen the effect of airborne allergens

There are several ways in which air pollution could make allergens worse:
- air pollutants can bind to pollen-driven particles and exacerbate allergies
- air pollutants might damage pollen cell walls, meaning that allergens can penetrate into the lower respiratory tract (6 (#ref))
- pollutants can reduce the threshold of response to allergens, meaning that people can experience allergic reactions at lower pollen concentrations when pollution levels are high (5 (#ref))
- air pollution can change how allergic some pollen and fungal spores are; despite limited research; for example, higher levels of carbon dioxide, ozone and sulphur dioxide have been shown to increase the allergen potency of Alternaria alternata and Aspergillus fumigatus
Location and exposure

Urban residents experience more allergies than people living in rural areas, partly because of the way in which pollen grains interact with air pollution (6 (#ref)). Climate change impacts biodiversity and speeds up plant growth rates, which impacts the composition and concentration of bioaerosols. An example of this is ragweed, which has been found to flower more quickly in urban areas that have high carbon dioxide levels, causing them to produce more pollen. Different populations are also exposed to different levels of allergens depending on their location, for example there are different composition and concentrations between rural areas and cities.

Policies that have an impact on pollution and airborne allergens

In an effort to combat climate change, the UK has a commitment to reach net zero by 2050 (7 (#ref)). Decarbonisation policies aimed at meeting this target, such as the transition to electric vehicles (8 (#ref)), could have significant health co-benefits for allergy sufferers because of their influence on air pollution.

Natural England’s Green Infrastructure framework has been put in place to support the development of green infrastructure which is good quality, partly as a way of improving resilience to climate change (9 (#ref)). As part of this, it is important that developers use low allergenic plants, trees or solutions when implementing green infrastructure, to minimise increases in local allergen levels and potency.

References

Chief Medical Officer’s annual report 2022: air pollution - GOV.UK (https://www.gov.uk/government/publications/chief-medical-officers-annual-report-2022-air-pollution) (viewed on 20 May 2025)

Public Health England, ‘Health Matters: Air Pollution’ (https://www.gov.uk/government/publications/health-matters-air-pollution/health-matters-air-pollution) 2018 (Viewed on 20 March 2025)

Hussey SJK and others, ‘Air pollution alters Staphylococcus aureus and Streptococcus pneumoniae biofilms, antibiotic tolerance and colonisation’ (https://enviromicro-journals.onlinelibrary.wiley.com/doi/full/10.1111/1462-2920.13686) Environmental Microbiology 2017: Volume 19(5) pages 1868-1880 (viewed on 11 April 2025)

Committee on the Medical Effects of Air Pollutants, ‘Review of the UK Air Quality Index’ (https://assets.publishing.service.gov.uk/media/5a749a66e5274a44083b8003/COMEAP_re) 2011 (Viewed 18 March 2025)

UK Health Security Agency, ‘Health Effects of Climate Change Chapter 6: Outdoor airborne allergic pollen and fungal spores’ (https://assets.publishing.service.gov.uk/media/6570509d3831ec0013c7496e/HECC-report-2023-chapter-6-aeroallergens.pdf) 2012 (viewed on 18 March 2025)

Sedghy F, Varasteh AR, Sankian M, Moghadam M, ‘Interaction Between Air Pollutants and Pollen Grains: The Role on the Rising Trend in Allergy’ (https://pmc.ncbi.nlm.nih.gov/articles/PMC5941124/) Reports of Biochemistry and Molecular Biology 2018: Volume 6(2) pages 219-224 (Viewed 20 March 2025)

Burnett N, Stewart I, Hinson S, Tyers R, Hutton G, Malic X, ‘The UK’s plans and progress to reach net zero by 2050’ - House of Commons Library (https://commonslibrary.parliament.uk/research-briefings/cbp-9888/), 2024 (viewed on 9 May 2025)

Department for Transport, Office for Zero Emission Vehicles and Anthony Browne, ‘Pathway for zero emission vehicle transition by 2035 becomes law’ (https://www.gov.uk/government/news/pathway-for-zero-emission-vehicle-transition-by-2035-becomes-law) 2024 (viewed on 18 March 2025)

Natural England, ‘Green Infrastructure: the catalyst for Urban Greening’ (https://naturalengland.blog.gov.uk/2025/02/03/green-infrastructure-the-catalyst-for-urban-greening/) 2025 (viewed on 9th May 2025)