Bristol's mayor has signed a letter pledging to go further than the UK government in tackling air pollution - two weeks after announcing the city's Clean Air Zone was delayed once again.
The Clean Air Zone will mainly tackle nitrogen dioxide levels while this latest pledge covers another pollutant, PM2.5, which an expert said is largely caused by log burners and traffic. The letter signed by mayor Marvin Rees and more than 20 local and regional authorities across the UK pledges to bring the harmful pollutant to below 10 micrograms per cubic metre by 2030 - ten years ahead of the Government target.
Last year, the WHO reduced the guideline for annual average exposure to PM2.5 from 10 to 5 micrograms per cubic metre. Marvin Rees, Mayor of Bristol, said: “We have taken several steps to improve Bristol’s air quality. Recent major transport improvements have improved traffic flow, rerouted polluting vehicles from areas with low air quality, and given greater priority to public transport, walking and cycling.
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“We’re continuing to make transport in Bristol more environmentally sustainable to support people to switch to cleaner ways of travelling. We’ve worked with First Bus to introduce biogas-powered buses, which cut greenhouse gas emissions by up to 85 per cent.
"Earlier this year we introduced free electric vehicle trials for businesses and launched the region’s new £7 million electric vehicle charging network. We’re also supporting businesses to switch to greener ways of transporting goods with a target of 95 per cent of all city centre deliveries made by zero-emission vehicles within 10 years.
“Reducing car journeys, especially shorter ones, will help us reduce particulate matter pollution from tyres, brakes and road dust. We’ll also be doing more to raise awareness and help people understand the harmful health impacts of wood burning stoves, open fires and bonfires.
“The council can’t improve air quality alone. Reducing particulate matter concentrations is crucial to cutting premature death caused by pollution and the government’s unambitious target of 2040 will not lead to any real additional action or benefit.
"Along with other city leaders, we’ve urged the Environment Secretary to adopt the World Health Organisation’s 2030 target and provide local authorities with greater support. A large proportion of particulate matter pollution, up to 60 per cent, originates from outside of Bristol and one of the biggest sources is farming. This is why national action and government intervention is so vital to help us create a healthier city and quickly realise the benefits of cleaner air.”
'More hot air'?
However, David Wilcox, Green shadow cabinet co-lead on transport and active travel, said: "While it is encouraging that the mayor is signing up to these targets, a pledge does not make the air clean – without action to do so, it is just more hot air.
"If the administration is taking this new air quality commitment seriously we hope to see a serious plan to realise it and a major change in direction on transport. Because private cars are a major source of PM2.5 through tyre and brake dust, we urgently need to do much more in the city to make it easier for people to walk, cycle or take the bus instead."
Green Councillor Martin Fodor added: "It’s quite something to see the Mayor sign a letter calling for tougher action on air pollution just days after he has delayed the launch of Bristol’s Clean Air Zone (CAZ) yet again.
"However, Greens support this pledge, and will work hard to achieve it once the Mayor has left in two years’ time. As a first step to reaching this target we will likely need more pollution monitoring sites around Bristol to measure the city’s problem areas and major emitters."
Dr Jo Barnes - associate professor of clean air at the University of the West of England - said Bristol is already relatively close to the WHO air pollution limits for PM2.5. The expert said the pollutant is monitored in two sites in Bristol - in Bedminster and in St Paul's - and that the latest available for those is 2020.
With the limit being 10 micrograms per cubic metre, the latest data for the Bedminster one was 11.8 while the St Paul's one was 9.7, she said, before adding the figures fluctuate. "2020 was a lockdown year and we have not had the 2021 data yet, it should be published this month," she said. "I would probably expect it to have gone up slightly."
The associate professor described getting to that limit by 2030 at a local authority level as "quite achievable" and realistic, but that a lot of PM2.5 dos not come from local sources. Dr Barnes - who is part of the Air Quality Management Resource Centre - said the biggest local sources are log burners and traffic, adding the pollutant has become a bigger problem in recent years due to domestic use of log burners.
In terms of what can be done at a local level to bring down the pollutant, the expert said the council would need to control the use of log burners by raising public awareness and also by regulation. She gave the example of new regulations that have come in around the sale of wood, saying that wet wood is a lot more pollutant than seasoned wood.
The Clean Air Zone will control nitrogen dioxide levels which is related to traffic and legal limits are exceeded in several roads across the city, the expert said. The Clean Air Zone was initially due to come into force in October last year, but has faced repeated delays.
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