Listening to the discussion over Ulez expansion feels like an action replay of the way in which many were convinced to overreact to Covid, leading to policy responses which caused significantly more harm than good. The Ulez ‘discussion’ has all of the same elements, with modelled health benefits calculated by Imperial College and Mayor Khan’s justification that he is “saving lives”, implying that opponents are wannabe murderers. Of course, this time around, the public is thankfully much more sceptical.
In this short note, we wanted to set out how those ‘lives saved’ numbers are derived and to demonstrate that at best the numbers are seriously misrepresented and at worst completely wrong. In fact, applying the Government and Imperial’s own logic, there is a very strong case to say that the expansion of Ulez will, on balance, harm Londoner’s health when considering the downstream economic consequences of this policy.
The major flaw in Imperial’s model is the one-dimensional nature of its assumption that air pollution drives health and life expectancy. In the real world health is driven by a number of interacting factors with income being the primary driver. There are many assumptions one could dispute that (perhaps unsurprisingly) work towards inflating the claimed health benefits of reducing air pollution, but we focus only on the flaw of largely ignoring policy consequences.
The Imperial team presents several numbers, including: attributable deaths (3,600 to 4,100), improved life expectancy (five to six months) and life-years saved (6.1 million). We wanted to focus on the claimed benefits of the Mayor’s Transport Strategy in terms of life expectancy and life-years saved.
Before leaving attributable deaths, it is important to note that these are not in any sense deaths that can be avoided, nor are they deaths that are subject to reduction by the Transport Strategy. The figure appears to compare current death rates with death rates if all human emissions had been removed for all prior periods. It is a theoretical construct (similar to an unmitigated pandemic) and only a small fraction of this number would be theoretically impacted by road transport (around 15%). Only the going-forward numbers (life-years saved) relate to the Transport Strategy and there the benefits are relatively low at 0.4%. It is important to note that there has only ever been one death, of a young and chronically unwell girl ever recorded in England (56 million population) where the death certificate mentions air pollution. Tragic as this death clearly is, it again highlights the disconnect between the theoretic