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Our Air Quality expert, James Hewitt, is keen to engage with local people, particularly school children, about how we can work together to improve the air we all breathe.

Given its health and economic impact, air quality is of interest to those who live, work, and invest in St John's Wood - and comparable locations elsewhere. Greenhouse gas aside, the pollutant of greatest current concern is nitrogen dioxide (NO2), the main source of which is emissions from diesel vehicles (both old and new, private and commercial). NO2 is particularly harmful to children.

The St John's Wood Society is monitoring the concentration of NO2 at about 30 sites in the area. Doing so at least every second month for a year is necessary in order to take into account substantial variation between summer and winter. Ground temperature is usually greater during the former than the latter. Hot air tends to rise. This, like wind, helps disperse pollutants. The first year's sets of results are unsurprising. They indicate that, as predicted, average concentrations over the full year exceed the legal limit along the busiest roads and are unhealthy adjacent other through routes. Levels reduce in spring and summer but increase as it gets colder. As we have now been collecting results for 1 year, we are able to provide average readings for the year which are still sobering to look at. All results are available from this page, using the link at the bottom. This provides latest results and by clicking on each of the maps, previous versions are available.

‚ÄčThe results provide a useful comparison with continuous measurements made at specific sites out of our area for regulatory purposes - click here. Those continuous measurements indicate that annual average concentrations of NO2 were declining slowly prior to 2017 and that the decline has accelerated since then at Swiss Cottage and Marylebone Road (for reasons which are not yet clear). The results of the Society's measurements are consistent with those by colleagues in neighbouring parts of London - click here, and with computer models which have mapped air quality across London - click here. The results also provide a baseline to help assess the impact of major projects, such as CS11.

In addition to NO2, the Society hopes to monitor other air pollutants, notably PM10 and PM2.5 (small particles, some of which derive from exhausts, tyres and brakes). The preferred measuring device would help both to identify the time of day and location of pollution hotspots, and to optimise remedial action. Less traffic and a related shift in lifestyles would offer opportunity - and would be consistent with climate change imperatives.

All Air Quality results available here


Air Quality Results

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