11 © Centre for Economics and Business Research to improve air quality and that it worked “best” when combined with a broader set of policies that reduced emissions. With the reduction in traffic and the increase in less polluting vehicles recorded it is clear that emissions must have reduced and the TfL report highlights that this is so. But the Imperial College study shows little impact on air quality and the medical analysis8 shows no improvement in respiratory quality. It is probably too early to make a full assessment of the health impacts and a long term cohort study is indeed under way which should eventually provide results for this. 3.9. Conclusions ULEZ so far has cost Londoners £253 million per annum of which £167 million is additional revenue to GLA. The economic cost (deadweight plus admin) is £199 million per annum. 8