| Comment | I'll take "shit the article doesn't say" for ten.
> First, the zones work, if they are [sufficiently ambitious](https://guardianbookshop.com/the-invisible-killer-9781911545514.html). In 2010, the health benefits from less air pollution in zones in 25 German cities were estimated to be between [€760m and €2.6bn](https://www.sciencedirect.com/science/article/pii/S0965856415001159?via%3Dihub).
>
>In 2008, London’s first low-emission zones led to [improvements](http://content.tfl.gov.uk/travel-in-london-report-3.pdf) in particle pollution from traffic along busy suburban roads.
>
>Tightening the zone in 2012 created [further improvements](https://www.sciencedirect.com/science/article/pii/S136192091300059X?via%3Dihub), compared with areas outside the capital, but progress became slow and patchy, leading to a projection that it would take [London another 193 years](https://www.sciencedirect.com/science/article/pii/S0269749118321687?via%3Dihub) to comply with legal limits.
>
>The ultra low emission zone, or Ulez, started in 2017 in central London. By October 2022 it had [reduced nitrogen dioxide](https://www.theguardian.com/environment/2023/feb/24/pollutionwatch-london-ulez-cuts-traffic-fumes-but-heating-is-concern) from traffic by 46%. The benefit across inner London was 21%. |
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