Clearing the air

Clean air zones are being introduced to cities around the UK in an effort to reduce often damaging levels of air pollution and also to cut carbon emissions as part of efforts to tackle the climate crisis.


So what is a clean air zone? It's a designated area - perhaps bounded by specific roads - where targeted action is taken to improve air quality, usually by discouraging more polluting vehicles from entering the zone, for example through a daily charge.


Already in London, they are being introduced in five more cities - Birmingham, Leeds, Nottingham, Derby and Southampton - following a Government consultation in 2016 to develop a clear air zone framework, with a view to using the findings to implement more in the future. According to the framework, "these zones aim to address all sources of pollution, including nitrogen dioxide and particulate matter, and reduce public exposure to them using a range of measures tailored to the particular location."


The five cities will be a mix of charging and non-charging clean air zones. As the names suggest, in the charging zones drivers of certain vehicles will have to pay a fee to enter. In non-charging zones, city councils are expected to implement a range of measures to reduce pollution without making drivers pay, such as new public transport initiatives, extending cycle paths and developing more green spaces.


Another good way to reduce emissions in our cities is to encourage increased use of electric vehicles, with more charging points available to encourage people to make the transition. The shift to renewable energy sources for providing electricity in our cities will have a big impact too as the air pollution from fossil-fuelled power stations can travel long distances, particularly during windy and stormy weather conditions.


London has had a low emission zone (LEZ) in place since 2008 and in 2019 upgraded it to be even more stringent. It is now the ultra low emission zone (ULEZ). So what impact has the past decade of reduced air pollution from cars had on the city's environmental status? According to a study published in 2019 by the National Institute for Health Research (NIHR), based on research carried out between 2009 and 2014, the LEZ has seen some measures of air pollution reduced.


The study showed that during that time, average inner city background nitrogen dioxide (NO2) reduced from 50 to 45 micrograms per cubic metre (μg/m3), and at roadside locations from 75 to 68μg/m3. The health impacts in these studies showed some small improvements but with greater reductions in pollutants it is expected that benefits will increase more rapidly. As well as making the accepted levels of emissions more stringent, the city is introducing other greener travel initiatives.


Since 2018 all new London double-decker buses are hybrid, hydrogen or electric; the city's worst polluted 'hotspots' will have 12 new ultra low emission buses in operation by the end of 2019; and 5,000 older buses will be upgraded to be ultra low emission by October 2020. The combination of these measures and the ULEZ are expected to deliver a reduction in exhaust nitrogen dioxide emissions of up to 45%. The ULEZ and other clean air zones being introduced in the UK's cities are, over time, expected to show significant improvements in both air quality and public health.