UK Election 2024: Lib Dem manifesto pledges change on air pollution

Jun 20 2024

Given that this year’s general election came as a surprise to everyone except the Conservative Party, it’s a little odd that the Liberal Democrats are first out of the gate with their manifesto. Nevertheless, it’s here – and it features a simple but ambitious policy on air pollution.

Sounding rather bland and innocuous, the passage from Chapter 12 reads:

Pass a Clean Air Act, based on World Health Organization guidelines, enforced by a new Air Quality Agency.¹

Pretty bog-standard, corporate wording, right? Devil’s in the details...

How much will Lib Dems change UK air pollution regulations?

To demonstrate just how much of a leap forward for the UK’s air quality this would represent, all that’s needed is a simple comparison between our current guidelines and those now recommended by the World Health Organisation (WHO) as of 2021.² As new research demonstrated increased harm from a number of regulated air pollutants, the WHO decided to tighten their values in 2021, leaving the vast majority (around 96%) of countries behind – if we were to achieve what the Lib Dems are aiming for, we’d be part of a very exclusive club that only included Australia, Estonia, Finland, Grenada, Iceland, Mauritius, and New Zealand in 2023. Let’s take a look at the figures:³

Air pollutant	Current UK regulations (2020)	WHO recommendations (2021)
PM_2.5	Annual mean, 20 μg/m³ (England) and 10 μg/m³ (Scotland)	Annual mean, 5 μg/m³; 24-hour mean, 15 μg/m³
PM₁₀	Annual mean, 50 μg/m³ (Rest of UK) and 18 μg/m³ (Scotland); 24-hour mean, 50 μg/m³ (UK)	Annual mean, 15 μg/m³; 24-hour mean, 45 μg/m³
Nitrogen dioxide (NO₂)	Annual mean, 40 μg/m³; 1-hour mean, 200 μg/m³	Annual mean, 10 μg/m³; 1-hour mean, 200 μg/m³; 24-hour mean, 25 μg/m³
Ozone (O₃)	8-hour mean, 100 μg/m³	8-hour mean, 100 μg/m³
Sulphur dioxide (SO₂)	24-hour mean, 125 μg/m³	24-hour mean, 40 μg/m³
Carbon monoxide (CO)	8-hour mean, 10 μg/m³	8-hour mean, 10 μg/m³; 24-hour mean, 4 μg/m³

Now, assuming that concentrations of these regulated air pollutants remain at or just below current thresholds, bringing the UK’s air quality into alignment with the World Health Organisation’s wishes would require, in the most extreme cases, a 500% reduction in concentrations! But, as research on US hospital admissions suggests, reducing the average PM_2.5 concentrations from 9.7 μg/m³ (the US’ average during the study period) to the WHO’s 5 μg/m³ could reduce admissions for overall cardiovascular complaints by 23%.⁴ Given that, in 2023, the United Kingdom’s annual mean concentration at urban background sites was 7.2 µg/m³, we could be looking at roughly 10% fewer Britons falling ill from cardiovascular ailments.⁵

Indeed, some of the actual averages already meet the WHO’s standards, with the annual mean for PM₁₀ in 2023 at 12.3 μg/m³ ⁵ and the 8-hour mean for ozone at 66.8 μg/m³.⁶ And to be fair, the annual mean for nitrogen dioxide was 14.2 μg/m³ in 2023⁷, not that far off the recommended 10 μg/m³. So, whilst the Liberal Democrats’ pledge could seem quite the challenge from the perspective of current UK regulations, their lower threshholds are actually far closer to the real concentrations in British air.

¹For a Fair Deal: Manifesto 2024. Liberal Democrats. 2024.

² WHO Global Air Quality Guidelines. World Health Organisation. 2021.

³ National Air Quality Objectives. Department for Environment, Food and Rural Affairs. 2020.

⁴ The Updated WHO Air Quality Guidelines are a Big Step Forward but Not a Complete Solution. British Medical Journal. 2024.

⁵ Air Quality Statistics in the UK, 1987 to 2023 – Particulate Matter (PM10/PM2.5). Department for Environment, Food and Rural Affairs. 2024.

⁶ Air Quality Statistics in the UK, 1987 to 2023 - Ozone (O3). Department for Environment, Food and Rural Affairs. 2024.

⁷ Air Quality Statistics in the UK, 1987 to 2023 - Nitrogen Dioxide (NO2). Department for Environment, Food and Rural Affairs. 2024.