About 10 years ago I was called to give evidence before the Greater London assembly. I sat in a basement committee room with assembly members lined up behind a table and the public around us. The first question really surprised me; I was asked when we would have enough health evidence to justify action on air pollution.
Even 10 years ago the number of scientific studies was overwhelming. A few years earlier, in 2007, St George’s, University of London, assembled a database that allowed them to compare 3,377 results from different studies. This just looked at impacts that could be seen over a few days rather than the harm that accrues over years.
