Air quality data

Recent air quality readings show levels going back to what they were pre-Covid. So have the Dulwich LTNs had any effect at all?

One of our supporters recently pressed Southwark for up-to-date air quality monitoring data and received an unpublished table from Southwark Highways on 19 June 2023.

As you can see if you click on the link above, NO2 emissions have significantly increased each year from 2020 to 2023. They are not quite at 2019 levels yet, but this makes sense given that traffic is only slowly returning to pre-Covid levels.

But this also raises questions about what effect the Dulwich LTNs (installed and then modified in 2020, and changed further in 2021) have had on air quality. A big impact? Not much? None at all?

In his latest response on 24 August, Cllr McAsh says, “I completely agree that one of our top priorities should be cleaning our air.” However, he then goes on to say that it is notoriously difficult, at a neighbourhood or street level, to identify patterns in air quality that can be clearly linked to specific local interventions. “The weather, in particular, plays a major role.”

In other words, the Council believes there can be no conclusions drawn from its air quality data about whether LTNs improve air quality or make it worse. At the same time, the Council doesn’t appear to have any other tools or methods that would help it to analyse this. Given that improving air quality was one of the key reasons put forward for introducing LTNs in Dulwich (which wasn’t a natural fit given its poor public transport), this inability to measure the impact of LTNs on air quality undermines a key argument for retaining them.

Whatever his misgivings about the Council’s air quality data, we suspect that Cllr McAsh will be particularly worried by the 24% incease in NO2 levels recorded between 2022 and 2023 by a monitor on East Dulwich Grove, close to the junction with Lordship Lane, which now shows NO2 levels similar to the South Circular. It’s in his own ward – he’s the local councillor for Goose Green.

Cllr McAsh talks in his response of 24 August about improving traffic flow at this junction to prevent tailbacks. Is he hoping that this will sort out the sudden increase in NO2 emissions here? If so, how will this be measured?

Maybe the Council is just hoping that the wind will blow it all away.