please empty your brain below
How many measuring stations were used? For example, there is a measuring station in Wallington High Street in the Borough of Sutton. That high street (part of the A237, a north-south artery) is on a hill and has a set of traffic lights and two light-controlled pedestrian crossings so all that stop-start results in a lots of braking and revving. Should the results from that testing station represent the whole Wallington area or just that high street?
This also links in with the need for politicians to be seen to be doing something, he could shrug his shoulders, and say most of the pollution is outside his control, but the sort of people who vote for Labour in London, expect the people they vote for to do their bit, as an example to others.
That 'worrisome' measuring station in Wallington doesn't actually measure PM2.5, only nitrogen dioxide and PM10.
dg writes:
"For PM2.5, there is a gradient in concentration across the country with higher concentrations found in the South East than other areas."
As I understand it, London's annual average is significantly affected by high concentrations on the minority of days when the wind blows from the east.
I would have thought though that electric cars would help reduce particulates from brake wear as they would have regenerative braking which would avoid the bulk of brake wear.
It would be interesting to know what the contribution of:
1) electric/hydrogen buses
2) hybrid buses
3) pure diesel buses
4) tube trains
5) London Overground and TfL Rail trains
is to this.
In the case of the deep-level tube, at stations I suspect it is quite high and probably the logical place to start - not least because it is entirely within the Mayor's control. Might not be what he wants politically though.
dg writes: In Hackney, for example, road transport contributes 100 times more PM2.5 than rail transport, and cars produce 4 times as much as buses.
Most of the M25 is outside the GLA area and therefore not shown on the map. It forms the boundary in the Waltham Cross and Heathrow areas, and cuts across the easternmost extremity of Greater London, and slightly elevated levels can be seen there.
In any case motorways, despite having higher volumes of traffic than the radial routes and the North Circular, probably produce no more particulates as (most of the time!) traffic is moving smoothly, with engines turning at their most fuel-efficient speeds and little use of the brakes.
I think you'll find that quite a lot of us are in favour of tougher regulations. Electric cars aren't going to be the answer in London though, unless the gov't embarks on a gigantic spree of building charging stations.
https://uk-air.defra.gov.uk/library/annualreport/viewonline?year=2015_issue_1 (page 70)
I remember the smog in the 1950's which you could see, today we have a more invisible but still harmful to health pollution.
Not certain but I notice the normal westerly wind that blows across the UK seems to be replaced by an east or south east wind more frequently these days.- I live near Heathrow and notice the prevailing wind by the direction of the planes approach or take off.
The message needs to get across switch off your engine if you are going to be standing for some time.
Get rid of the road humps that cause cars to slow, brake and then speed up again, causing higher pollution.
Fit cameras on street lampposts to replace the road humps and fine the speeders.
Remove many of the traffic lights in London, keep the traffic moving.
It won't be measured by these particular particulate figures, but I'm sure there must be an effect. Why isn't more being said about this?
Electric cars, but increasing numbers of aeroplanes. Madness.
Some people don't care, some people intend to move away as soon as they can afford to, and for some people, perhaps such as people from Sofia and Warsaw, they moved to London to improve the quality of air they breathe.
And I agree with my namesake from 2 hours ago - whether deliberately or organically, the roads in London seem to encourage braking and accelerating again as much as possible.
I don't have any statistics, but anecdotally it seems to me that private cars are not really the problem, it is vans and trucks, which for some reason want to clog up the roads at the time people are commuting. (DG's post from Tuesday suggests why some people may still prefer to commute by car rather than public transport.)
dg writes: I do have some statistics, for Tower Hamlets, so can confirm that private cars are the biggest problem (approximately half of PM2.5), ahead of vans and trucks (approximately one-third)
And of the private cars that you see in London, I wonder how many are actually minicabs or carrying somebody too important to care about the congestion charge.
Can anyone say whether buses and taxis have anything like this, because - God knows - they're the ones that could best use it, to save pumping out fumes every time they stop?
dg writes: Yes, newer London buses do.
(I believe not, because the last time I was on a bus there was a change of drivers and the engine was left running the whole time)
I wouldn't expect TfL to change every bus in the capital to electric in X number of years... but surely there are improvements like that that they could be making to their existing vehicles, at relatively small expense, and in relatively short time, right here in the present ???
dg writes: TfL are indeed doing both of those things, Roger.
Thanks DG for your correction / clarification and explaining how the level is derived.
With apologies for not having the time to read the report (yet), I shudder when I read the word, 'modelled'.
To me, the only truly representative way would be to have a reading taken as close to the exact centre of each of the 25,000 grid squares, and at 1.5m off the ground (nose height).
Given the impossibility of this, then it would also be acceptable to replicate data across similar grid squares to some degree, but that should be the limit of any adjustments to the raw data.
Apparently NOx emissions from aviation have doubled since 1990. (https://www.theguardian.com/environment/2016/jan/29/air-pollution-from-europes-planes-set-to-rise-by-nearly-half)
I remembered a study of O'Hare airport in Chicago... a few details here...
http://www.areco.org/rosscriteria.pdf
"O’Hare aircraft have significantly greater NOx, VOC and CO emissions than do typical electric generating plants, whether defined as typical within the entire U.S. or within Illinois or just Cook County. O’Hare aircraft VOC emissions are greater than those from all of Illinois power plants combined while CO emissions are as high as 60% of the amount from all of these plants combined."
Pollution from aeroplanes is being conveniently overlooked, and under-estimated.
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