I'm all for improved monitoring methods, especially direct air pollution monitoring, to use for future comparisons. But you refuse to even acknowledge the question I'm going to ask for the last time: We need to make a comparison to pre-installation traffic levels. Is it better to use the same, flawed, methodology to make that comparison or to use a different methodology pre and post installation?
Since you have failed to produce a single peer reviewed study to support your view I'm now certain that you will reject all academic studies that are broadly positive as being from biased "active travel academics" so there's really no point in continuing to discuss with you. No matter what monitoring is done, if it doesn't match your perception of things, you will call it false and gaslighting, so we are done here.
Peer reviewed journals withdraw articles after publication when they are shown to be wrong, most famously I guess being Wakefield's fraudulent MMR-autism bullshit. istr you posted an article which said a 2021 study by imperial college was withdrawn so that should give you confidence that the full process works, and that articles which aren't withdrawn still provide honest and useful information despite the flaws. Much better than newspaper articles which can't be criticised because they don't tell you anything about what they have done to come to the conclusions they have.