The easily visible impact of coal smog in London in 1952.

It was widely reported that London overshot its entire 2017 air pollution target within the first five days of this year and air quality has been in the news a lot lately, from diesel emissions to the two high profile court cases from Client Earth due to the UK breaching EU air quality limits and also repeated warnings from the European Commission itself. The London Mayor has also highlighted improving air quality as his number one priority.

At my ‘environmental quality’ session at the joint Royal Society and Defra conference ‘Science for Defra: excellence in the application of evidence, I focused my plenary talk on the importance of individual high profile events throughout history in driving policy development at both a national and international scale.

The UK, in common with most European countries has substantial air quality problems, especially due to particulate matter, nitrogen dioxide and ozone affecting human health and ecosystems. However despite the alarming tales of air quality and health I also described a tale of success in greatly improving air quality in UK cities from the sulphur and coal smoke smogs of the mid 20th century . The environmental quality community has a lot to be proud of.

We had terrible environmental quality problems in the mid 20th century, when most industrial cities had exceptionally poor air quality. Take London’s Great Smog of 1952 caused by coal power plants and domestic coal use combined with a spell of cold calm weather. This smog led to the Clean Air Act of 1956. The Clean Air Act led to a gradual improvement in air quality, but the continued large scale emissions of sulphur dioxide resulted in acid rain – which was once common across Europe with widespread damage in Scandinavia and Eastern Europe, this led to the Geneva Convention on long range transboundary air pollution (sulphur protocol) of 1983 and the Gothenburg Protocol of 1999. Since the 1960s, sulphur emissions have reduced by two orders of magnitude and this has resulted in the gradual recovery of fresh waters across Europe. Both of these examples illustrate the impact that event inspired, scientifically-informed transboundary policymaking can have.

So can the concerns surrounding particulate matter and diesel engines motivate this same kind of policy momentum? The impacts of air pollution on the environment and human health aren’t always as obvious as dense smogs, or acidified lakes. In addition, it seems difficult for experts to predict the exact health impact of air pollution, or for the media and health professionals to clearly communicate this (excellently explored by David Spiegelhalter FRS in this blog). As David states, people no longer drop dead from air pollution as they did back in the 1952 London smog – the impact on health is more subtle, possibly just exacerbating existing conditions of the heart and lungs, making it harder to grasp.

However, the health impacts from air pollution are again on the rise, resulting from increasing particulate matter, nitrogen dioxide and ozone pollution (and their interactions) in our cities. A wider synthesis of evidence from multiple sources as well as continuous monitoring, alongside better inventories and modelling is required from the scientific community. Overall, the science on many of these pollution topics is fairly robust, and some would argue that relatively little new evidence is required to translate this into policy solutions. So, if we already know the health implications and how to tackle them environmentally, why have we not already solved these problems?

In the environmental quality panel discussion that I chaired, Harriet Wallace, Defra, Paul Monks, University of Leicester, Stephen Holgate, University of Southampton and Penny Johnes, University of Bristol joined me in discussion. Each had their own views on why pollution can be hard to address politically.

Stephen Holgate began by describing what he sees as the main failings in the air quality debate. Firstly, the lack of visibility and understanding among the general public of the health implications – out of sight out of mind. Particulate matter, nitrogen and ozone pollution are not easily visible and their impacts not straightforward or easily understandable. The health profession has a role in clearly communicating these risks. He also raised the issue of impacts on personal freedom, however, many have mixed feelings towards addressing air quality as solutions can directly impact on quality of life in a different way, for example the increased freedom that comes from owning a car.

New technology in the form of low emissions vehicles, affordable electric cars and fewer cars in city centres may represent a way forward. Other cities have signed a commitment to get all diesel vehicles off the road by 2025 including Paris, Madrid, Milan and Mexico City. Paris has already restricted the most polluting vehicles from its city centre. Berlin has installed pollution filters on buses and rubbish lorries and installed a strict low emission zone which bars older vehicles and heavy goods vehicles from the city. Cheap and efficient public transport has also reduced car use here (despite already being one of the lowest in Europe). As a result the most dangerous particulates – ultrafines – have fallen by 70% in just three years. In London, Mayor Sadiq Khan has already announced plans for an ultra-low emission zone.

The panel sessions at the conference were intended to challenge Defra in their use of science, as well as highlight Defra’s own scientific research and evidence needs. The discussion in this session certainly went both ways. Harriet Wallace expertly laid out Defra’s commitments on addressing the inventory of air pollution contributors, including farming, wood stoves and construction, and not just focusing on road transport. Alongside this Penny Johnes from the University of Bristol presented a captivating case for more attention to, and investment in, preventing nitrogen pollution (eutrophication) of waterways, which has become an increasing policy challenge from agricultural activities, especially livestock production.

Tackling many of these issues requires joining up local, national and international policy frameworks to improve both local and transboundary pollution issues. The UK government has launched an unprecedented joint select committee inquiry into improving air quality in 38 pollution hot spots across the UK. Unfortunately this has been delayed by the recent snap election, but we hope that upon re-appointment of select committees that The Environment Food and Rural Affairs, Environmental Audit Committee, Health, and Transport Committees will all hold sessions to consider evidence from both environmental and health scientists. This joined up approach appears vital for progress but it remains to be seen over the coming months whether this latest string of events will be enough to finally translate this solid evidence base into effective policy.

This is one in a short series of blog posts summarising the recent ‘Science for Defra: excellence in the application of evidence’ conference, held at the Royal Society on 29 and 30 March. For more conference outputs see the conference event page and keep your eye on In Verba for summary blogs of the other sessions by our Fellows.