Your data is really interesting – thank you for sharing it. If only there was more comprehensive monitoring to help explain why these increases are happening. Since August 2023, a number of changes locally may have contributed:
ULEZ expansion (August 2023): The expansion was intended to reduce pollution, but by shifting the boundary from the South Circular to the M25 it may have had an unintended effect. Once drivers are paying £12.50, they can travel through the entire inner zone, which could be encouraging more long journeys rather than fewer.
Brixton Hill LTN (September 2023): This pushed significant volumes of traffic onto boundary roads, creating longer queues and greater congestion – the very conditions that worsen air quality.
Sudbourne School Street (October 2023): Traffic previously dispersed through Branksome Road is now being funnelled back onto Brixton Hill. Parents may not drive directly past the school gates, but they are still driving – and still parking nearby, displacing rather than removing emissions.
Streatham High Road changes: The proposed redesign, coupled with existing congestion, risks concentrating even more vehicles on one of the most polluted corridors in London.
20mph zones and turning restrictions: The blanket application of 20mph limits, combined with the over-zealous use of no left turns, no right turns, and road closures, can increase journey times, cause stop–start traffic, and force drivers to take longer routes.
Loss of off-street parking: Removing parking without providing realistic alternatives has the unintended effect of motorists circling residential streets for longer periods of time, adding yet more emissions to already stressed areas.
Taken together, it raises a difficult but important question: are policies such as LTNs, ULEZ, and the web of restrictions being implemented by the Mayor, TfL, and Lambeth Council genuinely improving air quality – or are they creating a set of unintended consequences that may one day need to be reversed?
It's hard to speculate about the complex impacts of traffic movements and restrictions without scientific evidence, but fortunately, comprehensive monitoring of air quality has shown that the ULEZ expansion [1] and the introduction of LTNs [2] improve air quality without worsening air pollution on boundary roads.
Are you able to send me this data in a spreadsheet?
Your data is really interesting – thank you for sharing it. If only there was more comprehensive monitoring to help explain why these increases are happening. Since August 2023, a number of changes locally may have contributed:
ULEZ expansion (August 2023): The expansion was intended to reduce pollution, but by shifting the boundary from the South Circular to the M25 it may have had an unintended effect. Once drivers are paying £12.50, they can travel through the entire inner zone, which could be encouraging more long journeys rather than fewer.
Brixton Hill LTN (September 2023): This pushed significant volumes of traffic onto boundary roads, creating longer queues and greater congestion – the very conditions that worsen air quality.
Sudbourne School Street (October 2023): Traffic previously dispersed through Branksome Road is now being funnelled back onto Brixton Hill. Parents may not drive directly past the school gates, but they are still driving – and still parking nearby, displacing rather than removing emissions.
Streatham High Road changes: The proposed redesign, coupled with existing congestion, risks concentrating even more vehicles on one of the most polluted corridors in London.
20mph zones and turning restrictions: The blanket application of 20mph limits, combined with the over-zealous use of no left turns, no right turns, and road closures, can increase journey times, cause stop–start traffic, and force drivers to take longer routes.
Loss of off-street parking: Removing parking without providing realistic alternatives has the unintended effect of motorists circling residential streets for longer periods of time, adding yet more emissions to already stressed areas.
Taken together, it raises a difficult but important question: are policies such as LTNs, ULEZ, and the web of restrictions being implemented by the Mayor, TfL, and Lambeth Council genuinely improving air quality – or are they creating a set of unintended consequences that may one day need to be reversed?
Hi Will, thanks for the comment.
It's hard to speculate about the complex impacts of traffic movements and restrictions without scientific evidence, but fortunately, comprehensive monitoring of air quality has shown that the ULEZ expansion [1] and the introduction of LTNs [2] improve air quality without worsening air pollution on boundary roads.
[1] https://www.london.gov.uk/programmes-strategies/environment-and-climate-change/environment-and-climate-change-publications/london-wide-ultra-low-emission-zone-one-year-report
[2] https://www.imperial.ac.uk/news/241731/low-traffic-neighbourhoods-reduce-pollution-surrounding-streets/