At one time diesel vehicles were given tax concessions in the UK due to lower emissions of CO2 than petrol equivalents, but that tide is turning now.
London’s pollution problem worsened this week – so much so that it briefly overtook Beijing in the filthy-air department for the first time – an alarming development widely attributed to the rapidly growing use of household wood burners, as iNews reports.
Readings on Monday afternoon showed that the air in parts of London contained 197 micrograms per cubic metre of ‘particulate’ matter, compared to 190 in the Chinese capital.
Dwarfed by human hair
Particulates are miniscule specs of dust, heavy metals and other fragments generated by diesel engines, manufacturing and central heating – the most deadly of which are less than 40 times the width of a human hair. These particles reach deep into the lungs and bloodstream, causing problems such as asthma, heat disease and strokes and responsible for an estimated 29,000 premature deaths a year in the UK.
The other major source of pollution is nitrogen dioxide – mostly from diesel vehicles, aviation, industry and railways, but not wood burning – which is behind for an estimated 11,000 early deaths a year in Britain.
As the London smog hit the national headlines, with schools hauling children in from the playground and Mayor Sadiq Khan taking to Twitter to bemoan “the shameful state of London’s toxic air”, many were blaming wood burners for the spike in pollution.
What is the culprit?
But was wood burning really to blame? The smoke escaping through the capital’s chimneys contributes around 5 per cent of the city’s particle pollution over the course of a year, according to King’s College London pollution expert Gary Fuller – noting that public health effect of wood burning is exacerbated because so many of the fires are in residential areas, increasing people’s exposure.
This figure jumps about considerably during the course of the day and the year – rising to around 10 per cent or more on particularly cold, still winter nights, when it’s late and the traffic has died down – and falling to virtually nothing in the summer.
“Wood burners are a serious and growing environmental problem that looks likely to get much worse in the next 20 years. They are already contributing to thousands of premature deaths in the UK each year – a number that is set to rise considerably between now and 2035,” said King’s College London air quality Professor, Martin Williams. He said that “very preliminary” findings suggest that by 2035, wood burning from households and businesses will have roughly doubled in London.
Data on wood burner pollution outside London is thin on the ground, although with wood burner ownership so much lower away from the south east it is regarded as less of a threat. But the problem is likely to spread across much of the country in the next 20 years, as wood burning looks set to steadily increase.
“People should think twice about burning wood because the particle emissions are much higher than using gas or electricity,” Prof Williams said.
Air pollution campaigners agree that wood burning is already an issue in parts of the country – and one that is set to spread. However, they point out that particles from wood fires are only responsible for a few per cent of the health problems stemming from London’s air pollution – and considerably less across most of country.
And even if the number of particles doubles, campaigners say the primary focus must remain on diesel vehicles, which are responsible for around half of the total air pollution in London and similar levels across much of the UK.
“While we need to tackle all major sources of pollution, including that from wood burners, we should not lose sight of the fact that the illegal levels of air pollution in our towns and cities all year round comes overwhelmingly from road traffic, in particular diesel vehicles,” said Andrea Lee, an air campaigner for the environmental law firm ClientEarth.
The iNews report continues here.
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A Transport for London technical paper says:
‘On average, a diesel vehicle will emit 22 times as much particulate matter and at least four times as much NOx as a petrol equivalent.’