ULEZ Expansion - Impact on the Underground?

It won't be every station within the M25. Theydon Bois, Debden, Loughton, Buck Hill and the Loop will not be in the ULEZ. All of these, other than Debden and the Loop, are very stringently parking restricted, so I wouldn't think the nett effect on saturation will be very high. Chingford overground is also on the very edge of the ULEZ. Between the station and the Forest is outside the ULEZ, but the other side is within it...

Isn't it designed to cause some people to change their travel patterns?

Yes, there is a court case under way, I think its safe to say that the expansion of the ULEZ zone is highly controversial. I see it as a present-era version of the 1950s clean air legislation which successfully ended the deadly air pollution smogs.

At around the same time as the clean air acts were enacted the railways started converting from steam to diesel traction, and in some cases, electric. This includes the Metropolitan line and several urban & outer suburban main line railway routes here in London. Moving away from steam would have also helped clean London's air, but to my eyes it seems a retrograde step that London Transport commenced the bus network conversion from electric to diesel traction at around the same time.

I have a friend who is in his 80s and walks with difficulty. He does not use his car very often and is very unhappy because if ULEZ is introduced throughout suburban London it will attract the daily fee.

I cannot help wonder whether the court action could have been averted if a compromise had been reached for a longer transition period and with lower fees for people who like him live in suburban London and just cannot afford a replacement vehicle.

From the London councils site:

"In London, 9,400 premature deaths are attributed to poor air quality and a cost of between £1.4 and £3.7 billion a year to the health service."

Even if only 20% of those deaths were attributable to car originating pollution, that's an awful lot of deaths over 15 years.

Rather than this blunderbuss approach to cleaning air, I would rather see a tightening of the (national) MOT emissions test to get smokey, smelly engines sorted, or off the road. Outside of London, I frequently have to set my car heater to re-circulate because of a stinker in front, even several vehicles away. Conversely there must be many aged cars, with low mileage that really are not a problem.

And also, a lot of "emissions" are actually from the tyres...

This really is the big question - where does all that dust and other pollution come from?

Are we focusing on the right targets. Actually ensuring vehicle testing is rigorous would be a great start especially as the current rarely supervised testing scheme carries the risk that all you need to do is find some folding stuff and the right person to sign off your test certificate.

I fear that once people start digging into this "can of worms" people will indeed realise that in addition to tyre wear other things like wear of brake disks and brake linings are also significant sources of fine particulate matter. Indeed the switch to generally much heavier EV models may actually make things a lot worse on all those counts.

I also have a nasty feeling that LUL already know there may be significant issues in relation to harmful dust/particle levels lurking in many tunnel sections of the tube. Perhaps the Mayor should be just as keen to act to save Londoners from this risk especially as he is the ultimate boss and immediately close the entire system down at least until they can build a proper tunnel cleaning train and regularly clean out the immense amount of dust lurking in the tunnels.

I was astonished to see just how filthy some relatively new sections were on the Hidden London visit to Finsbury Park. I hate to think what dust levels the track maintenance staff are expected to work in on a daily basis. How long will it be before the No win no fee fraternity focus on this money spinner?

Pass, I just put the registration number into the checker and it said I didn't need to pay the fee!

So, will you be driving it to the Coronation Special?

The mayori is driven in a Range Rover.

Of course not

Unless you measured every breath that everyone took, you must use gathered data with some kind of statistical model.

That certainly can be true, particularly of more complex models - or ones that depend on dubious or unproveable assumptions, but as I pointed out in the response you quoted, there is no other practical way.

In this instance, the model is fairly simple, and if you can find any dubious assumptions (e.g. that all problems are caused by fumes - ignoring other particulate generators), anyone is welcome to point them out.