UK can meet WHO PM2.5 guidelines, government says

The UK can meet World Health Organisation (WHO) clean air guidelines for PM2.5 in the coming years, a new government report has said.

The report assessed the UK’s progress towards getting its PM2.5 levels down to WHO guidelines and combined the findings of two reports commissioned by Defra — the first by Imperial College London and the second by King’s College London.

Defra said measures included in January’s Clean Air Strategy will take the UK a ‘substantial way’ towards achieving the WHO’s guideline annual mean limit for fine particulate matter (PM2.5) of 10 μg/m3 nationwide, reducing the UK’s exceedance of the limit by 95% from 2016 levels by 2030.

The report follows the former Environment Secretary Michael Gove’s confirmation last week that the government’s new Environment Bill will enshrine the WHO’s PM2.5 guideline limit in UK law.

While the report admitted that high levels of PM2.5 are likely to persist in areas such as central London, the government said it would be ‘technically feasible’ for the WHO guideline to be met across the UK in the future, based on scientific modelling.

However, the government warned that uncertain economic and practical factors such as climate change and urban density trends could make the target harder to achieve in the future.

‘We believe that, whilst challenging, it would be technically feasible to meet the WHO guideline level for PM2.5 across the UK in the future,’ the report concludes.

‘Substantive further analysis is needed to understand what would be an appropriate timescale and means, and we will work with a broad range of experts, factoring in economic, social and technological feasibility to do this.’

The scientists’ models found that in all scenarios, the UK’s population will have ‘substantially lower’ exposure to PM2.5 by 2030 compared to 2016.

Such a reduction would reduce the number of people living in locations exceeding WHO’s guideline by over 80% compared to 2016, and reduce the average exposure by 1-2 µg/m3.

The report also highlighted the substantial benefits that even a minimum reduction of emissions to meet WHO guidelines will have, bringing an estimated health benefit of £6.8bn per year, excluding costs to NHS and social care.

The government commented that the analysis did not consider potentially positive developments over the coming years such as behavioural change, technological innovations and the impacts of the UK’s new 2050 zero-carbon target.

However, it warned that the UK will rely on other countries to meet their own commitments in order to see the full benefits of its efforts.

‘Part of the benefit will be dependent on EU member states meeting their own emission reduction commitments, due to [the] transboundary transport of PM,’ the report said.

The government said it will now undertake further analysis and seek further advice to see how the 2030 target could be achieved.

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