WHO amends figures after Port Talbot PM2.5 data error

The World Health Organization has re-issued figures on particulate pollution levels in UK towns and cities — after it emerged that data for Port Talbot in South Wales had been incorrect.

Published last week, the latest update to the WHO’s ambient air quality database presented information on 2015 particulate levels in over 4,000 regions across the globe, which included figures taken from the UK’s air quality monitoring network (see story).

Data relating to air pollution emissions in Port Talbot has been amended by the World Health Organization

Initially the WHO data presented Port Talbot as the area in the UK with among the highest levels of PM2.5 and PM10 — which were recorded at an average level of 18 μg/m3 and 27 μg/m3 for the year — exceeding the WHO’s health recommendations of 10 μg/m3 (for PM2.5) 20 μg/m3 (for PM10).

However, the figures were challenged by Neath Port Talbot council, which claimed that the data presented by WHO had in fact been based on estimates of fine particle emissions, rather than monitoring data which suggested that PM2.5 levels were significantly lower than the estimated levels.

According to Neath Port Talbot, local monitoring data suggests that PM2.5 levels averaged around 9.6 μg/m3 for the year.


The data has subsequently been amended by the World Health Organization, which claimed that the error occurred due to an ‘oversight’ after it had received the correct figures from the European Environment Agency.

Data for the PM10 levels in the region, which stood at 27 μg/m3 — and were among the highest monitored anywhere in the country — remain unchanged.

Following the correction, WHO director of public health, Dr Maria Neira issued a statement apologising for the data error.

She said: “The World Health Organization has reviewed the air pollution figures published. After an in-depth review and in consultation with the European Environment Agency, we unfortunately detected an oversight.

“The PM2.5 level for the year 2015 for Port Talbot should be 9.6853 (and is rounded to 10 in the updated excel sheet) and is noted as “measured.”  The PM2.5 was erroneously featured as a converted (estimated) value of 18.

“The World Health Organisation has taken immediate steps to rectify this on its WHO web site, and in the Database. We regret that this error happened.

“We wish to reiterate WHO has brought together information on outdoor air pollution collected by cities worldwide in order to raise awareness and facilitate adequate responses to protect public health from the adverse impacts of outdoor air pollution.”

Related Links
WHO – ambient air quality database


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