Updated Withyhedge air quality assessment

Published: 26 July 2024

Public Health Wales is confirming findings from a further health risk assessment of air quality data collected around the Withyhedge landfill site, covering the period between 3 April and 26 June 2024.

The data suggests that levels of hydrogen sulphide in the air around the site have at times been above the World Health Organization (WHO) odour annoyance guideline. 
Public Health Wales advice therefore remains that residents should keep doors and windows closed when the smells are present, and to seek medical advice if they feel unwell.
Typically, when odours are above the WHO odour annoyance guideline value, there is potential for odour complaints and health effects.  Everybody reacts differently. For some, bad odours or smells can lead to headaches, eye irritation, nausea, dizziness, and unusual tiredness, even when the substances that cause the odour are themselves not toxicologically harmful to health
These are common reactions, and these effects should usually pass once the odour has gone.  The long-term (lifetime) health risk remains low. 
Hydrogen sulphide is a gas that has a rotten egg smell. Our noses can smell very small amounts of hydrogen sulphide, even at levels that are too low to cause harm.
Public health advice to those exposed to the odours remains unchanged.

• Closing windows and doors when nasty smells occur, or when the wind is blowing from the landfill towards your home, can help to stop smells coming inside.
• Remember not to block windows or vents completely.  This is because they provide air to vent cookers or heaters, and can help to control damp. 
• Once an outdoor smell has passed, opening windows and doors will help get rid of any smells that remain.

Public Health Wales maintains that reducing the cause or source of offsite odours from the landfill site must be a priority to reduce exposure and any potential health effects on the local community.
Dr Sarah Jones, Consultant in Environmental Public Health for Public Health Wales said:

“We recognise that local people continue to be concerned as a result of these odours, and that this air quality report continues to show levels of hydrogen sulphide above the World Health Organization (WHO) odour annoyance guideline.

“Public Health Wales remains eager to see a resolution to this situation.  The health risk assessment will continue to be reviewed and updated as more monitoring data is made available to us.”

The air quality assessment is based on monitoring carried out by GeoTechnology Ltd, a contractor employed by RML, the Withyhedge site operator, at several locations around Withyhedge Landfill site between 3 April and 26 June 2024.