"Keep your distance - I'm diesel"

7 September 2018

The concentration of nitrogen dioxide ("NO2"), a pollutant deriving primarily from the emissions of diesel engines is being measured by WCL Green Party volunteers at four sites in the Notting Hill area. This has involved fixing small "diffusion" tubes to lamp-posts every second month, retrieving these after four or five weeks.  

Chemicals in a membrane at the sealed top of each tube change during that time, depending on how much NO2 diffuses through it from the exposed lower end. The tubes are then sent to a laboratory so that the chemical composition of the membrane can be analysed - in order to determine the average NO2 concentration at the lamp-post. 

Three of the sites are near schools (partly in order to complement Client Earth's "Poisoned Playgrounds" campaign) - in Pembridge Square and at the south east and south west ends of Ladbroke Square Gardens. The fourth is at the junction between Pembridge Road and Westborne Grove.

Concentrations will vary over time - exceeding the daily average when vehicles collect or drop off pupils at schools and during rush hour. They can be worryingly large when vans or buses are idling.

Five sets of measurements have been made. Average NO2 concentrations at the latter site have changed the least and exceed the legal limit by at least 50%. Concentrations in Pembridge Square are the least, and have fluctuated most with the season - worse during winter than in summer. This reflects what one would expect. The level of NO2 at either end of Ladbroke Square Gardens is at or a little above the legal limit, due partly to through traffic, including buses.

The results are similar to those obtained by the St John's Wood Society around NW8. The research is likely to continue at least until the end of 2018 - particularly in order to indicate the long term trend. Monthly measurements being made by local government in RBKC and Hammersmith & Fulham suggest that the trend is downwards overall but only slightly so (- Westminster City Council no longer bothers to monitor air quality using diffusion tubes...). 

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For research into the (great) insufficiency of the proposed ULEZ in Greater London, go to minute 15:10 of https://www.youtube.com/watch?v=5xwDAE-OIz0&t=772s