IN SOME ways, it’s easy to be left-wing. You don’t have to know anything apart from some simplistic slogans. Just say ‘patriarchy’, ‘systematic racism’ or ‘climate emergency’ and that’s enough to justify most witless notions you believe. As the late Roger Scruton observed, conservatism is true but it’s boring because it doesn’t provide exciting slogans which make you feel good about yourself. If conservatives were to have a simple slogan it would probably be ‘It’s complicated’.

A prime example of a simplistic and misleading factoid is London Mayor Sadiq Khan’s claim that the capital’s ‘toxic air’ is killing 4,000 people a year. Khan is using this to browbeat those who question his plan to expand his Ultra Low Emission Zone (ULEZ) to outer London boroughs, requiring owners of older cars to pay £12.50 a day to drive. When challenged on this policy, he has accused political opponents of not caring about children dying from toxic air.

Like most left-wing factoids, the claim that thousands of people are dying from air pollution is barely questioned. However, an official query to the Office of National Statistics revealed that between 2001 and 2021 only one death had been recorded as being due to air pollution. So how does one arrive at 4,000 deaths a year?

There’s no doubt that air pollution can be toxic. The main culprits are nitrogen dioxide (NO₂) and tiny dust particles known as particulates, which are liable to cause breathing problems. Carbon dioxide – the villain for climate alarmists – is not a pollutant, merely an emission. New Labour didn’t understand this distinction and thus played with fuel tax to give incentives to diesel cars (relatively low CO₂ emission, high NO₂ and particulates) over petrol cars (high CO₂ emissions, low NO₂ and particulates), thereby increasing pollution. While high concentrations of NO₂ and particulates are bad for human health, the effects at lower levels and background concentrations are much less clear.

Khan’s 4,000 deaths figure comes from a 2021 report from Imperial College London, which is based on the modelling of air pollution effects by the Government’s Committee on the Medical Effects of Air Pollutants (COMEAP) in 2010. Experience in modelling involving Covid and climate change should immediately set alarm bells ringing. As with any of these models, examining the assumptions behind the pollution modelling raises several questions.

COMEAP attempted to establish the number of deaths arising from all man-made forms of pollution, although they state that it is ‘unrealistic’ to believe that all such pollution could be removed. They calculated national deaths from pollution by establishing a correlation between pollution levels and deaths (although correlation does not prove causation) and then projecting the number of deaths arising in the UK. COMEAP acknowledged that studies used to calculate a correlation between pollution and life expectancy included little data on the impact of pollution at low levels, so one couldn’t be sure of the effects of low pollution levels. Imperial College recognised this and calculated that if one excluded possible impacts at low levels, the annual number of deaths in London would be 2,200-2,600.

However, the deaths are not directly caused by air pollution, rather they are described as being ‘attributable’ to it. The COMEAP report states that it is ‘unrealistic to view air pollution as the sole cause of death in a number of cases equal to the population attributable deaths’. We have been here before with such tricksy language, such as distinguishing between people dying with or because of Covid. The COMEAP authors admit that the attributable deaths measure is one they were pressured to arrive at by politicians, who wanted a simple figure. The report authors preferred to express the effect of air pollution as a shortening of lives, and they estimated that at 2008 pollution levels Londoners born in that year would have their lives shortened by an average of nine months.

Pollution levels have fallen since COMEAP did their work, with NO₂ levels down 44 per cent and particulates down 18 per cent in the decade since 2010. Indeed, there have been large falls in pollution over the last 50 years, with nitrogen oxides down 72 per cent, and particulates down 73 per cent. The days of smog and pea-soupers in Britain are long gone.

As pollution levels are so much lower than previously, one wonders how much impact the proposed ULEZ extension will make. Sadiq Khan won’t say but if we take all the modelling at face value one can arrive at an answer. Accepting that pollution levels correlate with life expectancy, a reduction of pollution (averaging NO₂ and particulates) of about one-third since 2008 makes man-made pollution currently responsible for about a six-month (182 days) reduction in life expectancy in London. Hidden deep (page 186, as you ask) in an appendix of a report nestling with lots of other documents about the proposed ULEZ expansion is a table showing NO₂ and particulate reductions projected (more modelling!) from ULEZ extension. NO₂ will fall by about 1.25 per cent on average and particulate levels by 0.1 per cent (yes, that decimal point is in the right place). That means the ULEZ will reduce the number of polluted attributable deaths by between 4-50 a year (0.1 per cent and 1.25 per cent of 4,000), or increase average life expectancy by between six hours and two days.

When one has to make so many assumptions to arrive at an answer to a question that is so small, you know that the real number is either zero or so tiny that it may as well be zero. So expansion is an outrageous waste of taxpayers’ money. There will be many better ways to reduce pollution with a quarter of a billion pounds. However, that is not the point of the ULEZ: it’s now clear that the plan is to use the ULEZ cameras to implement a road-pricing scheme that will affect all London motorists by 2030. Knowing that Sadiq Khan chairs C40 Cities, ‘a global network of mayors taking urgent action to confront the climate crisis’, one can be certain that there will always be a pressing need to tax driving (and some ‘modelling’ to justify it).