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Latest Health Risk Assessment Results: Withyhedge Landfill

Published: 14 October 2024

Public Health Wales has undertaken a further health risk assessment of air quality data collected at the Spittal School monitoring station, covering the period between 27th August and 30th September 2024. During this time, there were occasions when hydrogen sulphide concentrations in the air were above the WHO odour annoyance (5ppb / 7ug/m3) level.

In addition, we have reviewed air quality monitoring undertaken by Geotechnology at other sites in the community between 9th August and 4th September 2024 and monitoring undertaken by Natural Resources Wales (also in the community) between 13th June and 4th September.  These monitoring data have recorded one occasion when hydrogen sulphide concentrations in the air were above the WHO odour annoyance (5ppb / 7ug/m3) level.

Whilst these data are generally reassuring, we do know that, even at low concentrations, bad smells can lead to headaches, nausea, dizziness, watery eyes, stuffy nose, irritated throat, cough or wheeze, sleep problems and stress. This can happen even when the substances that cause the smell are not directly 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.    

Closing windows and doors when 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.  

Multi agency partners review and check monitoring data together. Public Health Wales then use it to inform a health risk assessment before sharing our conclusions with the public. The health risk assessment will continue to be reviewed and updated as more monitoring data is made available to us.