London’s ultra-low emissions zone is making a difference.

[stannn]

https://www.theguardian.com/uk-news/2019/may/16/ulez-cuts-number-of-worst-polluting-cars-in-central-london

[HalcyonRichard]

Certainly reduced the number of polluting cas in the zone. But nothing about actual pollution reduction. Also are they measuring the adjoining areas. I can see a lot of polluters now going around the zone rather than a shorter distance through it. This would create more pollution overall.

Richard

[Countrypaul]

I wonder if not releasing any data on actual pollution levels is partly due to the difficulty in comparing it to previous levels? I can see that the weather would have an obvious influence, both in terms of rain (do more drive when its raining?), temperature, wind (if its windy pollution gets dispersed more easily), along with the timing of holidays (Easter moves year to year exactly when they started the new scheme), protests (how much of London was affected recently and what impact did that have?) and interaction of these.  Even things such as roadworks close to monitoring point, or causing changes to traffic flows near monitoring points could lead to misleading interpretation.

Wonder how long it will be before they are confident that the statistics are meaningful?

[azps]

I wonder if not releasing any data on actual pollution levels is partly due to the difficulty in comparing it to previous levels? I can see that the weather would have an obvious influence, both in terms of rain (do more drive when its raining?), temperature, wind (if its windy pollution gets dispersed more easily), along with the timing of holidays (Easter moves year to year exactly when they started the new scheme), protests (how much of London was affected recently and what impact did that have?) and interaction of these.  Even things such as roadworks close to monitoring point, or causing changes to traffic flows near monitoring points could lead to misleading interpretation.

Wonder how long it will be before they are confident that the statistics are meaningful?

Possibly about 3 years. Air quality data is very noisy.