Question to the Department for Environment, Food and Rural Affairs:

To ask the Secretary of State for Environment, Food and Rural Affairs, what recent assessment he has made of the effectiveness of the World Health Organization air quality guidelines on (a) odorous annoyance and (b) health in respect of hydrogen sulphide emissions from landfill sites.

The World Health Organization (WHO) air quality guidelines are internationally recognised guidelines. The UK Health Security Agency (UKHSA) has adopted the WHO air quality guidelines with respect to hydrogen sulphide for assessing odour and short-term exposure in their risk assessment for Walleys Quarry Landfill, available here: https://consult.environment-agency.gov.uk/west-midlands/walleys-quarry-landfill-sliverdale/user_uploads/walley-s-ea-aq-monitoring-health-risk--assessment-august-final.pdf.

The WHO guideline value of 7 µg/m3 (5 ppb) over a 30-minute averaging period is protective of odour annoyance. The WHO guideline value of 150 μg/m3 (107 ppb) as a 24-hour (average) to protect against eye irritation.