Guidance

Airborne allergens and green infrastructure

The UK government has set regulations to manage the health risks from airborne allergens like mould and pollen, as well as bioaerosols.

• From: UK Health Security Agency and Centre for Climate and Health Security
• Published: 7 August 2025

Applies to England

CCHS navigation menu:
CCHS homepage
Topic: environmental exposures
Air-related exposure: airborne allergens
Part of: Regulatory Guidance about Airborne Allergens

Key resources for green infrastructure:

• Airborne allergens and green infrastructure
  

• Biodiversity net gain
  

• Birch pollen and allergy for healthcare professionals - Allergy UK

The UK government has introduced the Biodiversity Net Gain (BNG) requirement under the Environment Act 2021 (1). Under the BNG requirement, developers must ensure a 10% net gain in biodiversity, meaning a development must leave a better quality natural habitat than was there prior to its creation (1). This could be through creating biodiversity on-site, or through purchasing off-site biodiversity units on the market, or through purchasing biodiversity credits (1). Local authorities should enforce these regulations and require biodiversity assessments and long-term ecological management plans to maintain and enhancing green spaces, wildlife habitats, and urban greenery.

While green spaces reduce pollution, they can also introduce airborne allergens like pollen that have health implications for those with respiratory conditions such as asthma (2). It is therefore important to select vegetation at new developments that contribute to biodiversity net gain whilst also minimising the pollen load (2). For example, birch trees are favoured by architects and are often included in urban planning but they are one of the main causes of seasonal allergies. Birch pollen can increase allergic sensitisation with 25% of hay fever sufferers affected by it (3).

References

1. Department for Environment, Food and Rural Affairs, ‘Understanding biodiversity net gain’ 2023 (Visited 20 April 2025)

2. Stevanovic K, Sinkkonen A, Pawankar R, Zuberbier T, ‘Urban Greening and Pollen Allergy: Balancing Health and Environmental Sustainability’ The Journal of Allergy and Clinical Immunology: In Practice 2025: Volume 13(2) pages 275 to 279 (viewed on 18 March 2025)

3. Allergy UK, ‘Birch Pollen and Allergy’ (Visited 20 April 2025)

Published 7 August 2025