The only complete trials are the one you mention on Embankment and another on Marylebone Road. TFL claim a reduction in PM10 of up to 14% from those trials, but they haven’t to my knowledge responded to criticisms such as those you make.

Has he come across any trial results ?

The only thing I have seen published are the TfL results from the initial exercise on the Embankment/Upper Thames Street which I thought were pretty flawed – and certainly not good enough to warrant the roll-out to many more sites at a cost of £1.2m.

The trial struggled to find a decent reference site to compare with the experimental site, it did not use the reference method for PM10 determination and signally failed to discuss any results from the reference method monitor already sited in the test road area.

It is also odd that the London experts in air quality (London King’s College ERG ) seem to distance themselves from the dust glue trial at every opportunity.

The technique was developed in Scandinavia to tackle dust from road break-up when cars with snow chains damaged road surfaces – as such I can believe it may have a place to work on construction sites. However, I am sceptical that diesel smuts have much affinity to “dust glue” – and to believe that they do and so mitigate the issue of dirty road traffic in Central London is damaging. London needs inner-city LEZ areas to keep the dirtiest vehicles out of the most-polluted places. Think Berlin.