It's a very dry paper, but here's the highlight: "The improvements in air quality induced by these policies have translated in wider productivity impacts as we demonstrate that [U]LEZ has reduced the probability of taking sick leave by 18.5%."

As someone with a modertately iffy respiratory system (my asthma isn't generally serious, but a cold will reliably do a number on my lungs), the combination of working from home full time post-pandemic (yes, I know, not over) and ULEZ has done more than anything to reduce my sick days. Earlier in my career, I'd be sick like clockwork 2-3 times a year, needing on average 2-3 days recovery time. Since 2020, I think I have taken 2.5 sick days total.

Broadly: more of this. All over the world, please.