Proposed London low emission zone.

I think the actual proposal is Euro 4 for petrol and Euro 6 for diesel. But you have to devil into the consultation document to find it. It was (unsurprisingly) written to press the maximum number of the Mayor's supporters' political buttons political buttons the maximum number of times.

thin on the economic effects of the charge, But the Mayor plays the politically adept card of calling for a scrappage scheme - to be paid for by _central_ government, not out of the income from the LEZ of course.

I'm not sure why hitting older petrol cars (which may well be run by Labour supporters) is going to be a good political move.

I do realise that something must be done as regards pollution in our larger cities. But I'd rather see something that would reduce that by a finite and considerable amount. Which is why I'd like some figures about how much better emissions from a 14 year old petrol car are over a 15 year old one.

I wonder if they will be looking at gas boilers next. Will they be fitted with catalytic converters to reduce NOx emissions too?

Yes it's very odd just to slap an age limit on cars. My car is Saab 9000

1995. Saab was ahead of the game then with low emission, I got the emmision reports at MOT:

CO 0.016 %, Limit 0.2% HC 10ppm, Limit 200ppm

Not that I'm holier than thou, I know that cars are a problem. But I think that these rules are just expedient because they can't find the data for older cars. CC charge doesn't bother me so much because I never drive to London in Business hours. But this is different.

Quite. I was remembering the figures from my prvious 98 BMW and wondered just how much better a modern petrol engine was supposed to be? By then it had variable valve timing, fully sequential injection, COP and lambda sensors both in and out of the cats. So was curious to know just what the big improvements in design are that have been made since?

Rather different with diesels which have still so much further to go.

The CC doesn't bother me either. Since parking is such a problem, I'd use PT anyway to visit that during working hours - even without a charge.

The N/S circular road area is very different. I use a short part of that when going to the shops. ;-)

It doesn't really apply to me though. My old car hasn't even got a cat, so fairy nuff. And my other one too new to be effected.

Our 97 Fiesta (1.25) record is

Year CO% HCppm Lambda

2000 0 10 1.19 (rear box exhaust leak fail) 2001 .01 4 1.01 2002 .01 13 1.00 2003 .01 6 1.00 2004 .01 8 1.02 2005 0 16 1.01 2006 0 14 1.01 2007 .01 15 1.01 2008 0 15 1.00 2009 0 5 1.03 (rear box exhaust leak advisory) 2010 0 5 1.01 2011 0 7 1.01 2012 0 4 1.00 2013 0 9 1.00 2014 0 8 1.00 2015 0 7 1.00 2016 0 6 1.00 2017 0 4 1.00

First time fail was 'cos the original owner (car hire Guernsey) had drilled a drain hole in the exhaust (2009 was a loose pipe clamp) - so it is possible for an older vehicle to be clean - though particulates and NOx are an unknown.

No intention of driving in London though :-)

Chris K

I may be misunderstanding what you want but the emission limits laid down for Euro 4, Euro 3 etc are of readily and freely available. So of course are the in-service limits for vehicles with emissions control systems. But I have no idea how the effects of the proposals have been modelled: I have only skimmed the con. doc. and there are appendices I've not even opened.

So how do I translate the MOT numbers into the standard's g/km ? M 1995 Saab 9000 car must originally have satisfied Euro 1.

The proportional reduction between Euro 1 and current Euro 6 for the g/km measures are according to RAC's website:

CO Euro 6/Euro 1 = 1/2.72 = 0.3676 HC Euro 6/Euro 1 = 0.1/0.97 = 0.1031

CO [1995 Saab car]/[upper limit] = 0.016%/0.2% = 0.08 HC [1995 Saab car]/[upper limit] = 10ppn/200ppm = 0.05

This indicates that my car is also well within the margin of Euro 6.

Any evidence for this ?. Labour supporters are more likely to have swallowed the 'diesel good, petrol bad' CO2 bribes offered by T Blair and Co, thinking that they were doing good for the planet.

I would have thought that the really older petrol cars would have been bought by people who don't follow politics, probably don't have English as a first language, so probably don't (or cannot) vote or are buying a cheap first car at 17.

NO2 is the biggest problem and diesels are the main culprits.

Thing is that many vehicles already exceeded those specifications when they were introduced. If you can grade vehicles by CO2 output for taxation purposes, why go to an age limit for this?

Does, for example, a state of the art emissions wise small car produced the same amount of pollution as the same age Ferrari, etc?

All cars of this age have an MOT. Why not measure all the pollutants at that time and make those which exceed the limits pay?

I thought they were going to banned after 2040 anyway ?.

I suspect it is easier to fine-tune a carbon burner that is not being asked to accelerate all the time (when emissions go up 10 times or more), and they aren't blowing emissions out at ground level.

Burning gas is the next culprit. And much worse in the more densely populated areas:

Don't be silly. 'Saving the plant' isn't confined to any one party. Despite the stereotypes.

15 years ago, there were more petrol cars than diesels by quite a margin. Not got figures as to what percentage of each has survived. Diesels with their more expensive engines and turbos etc may get scrapped earlier though due to uneconomic repairs. But only guessing.

Mine has what is effectively a lambda sensor in the flue, so self tunes.

Unfortunately fine tuning a burner might not help, when the best burner has the hottest flame temperature and so forms the highest levels of NOx.

I don't know how (if at all) the limits for the MoT in-service tests can be translated to Euro standards.

I can well believe your car has low emissions compared with others of its age, but I didn't follow the methodology of your calculations.

I did look and see that Saab reduced their emissions - as shown by the figures for the MoT test - in time for Euro 4:

Saab 1992 Onwards (with catalyser) Normal Idle Max CO 0.5% Fast Idle Max CO 0.3% Max HC 200 ppm

Saab 2004 Onwards (with catalyser) Normal Idle Max CO 0.3% Fast Idle Max CO 0.2% Max HC 200 ppm

(The 2004 on figures are the same as for my Euro 4 Focus.)

The numbers you see are for the Euro upper limits in force when the car was first registrered. The mistake made by the powers to be is that they assume the worstcase rather than the actual emmision as measured by latest MOT. My calculation suggests that my 1995 car would also satisfy Euro 6 on CO and HC.

Nonsense. Boiler flues generally discharge at a high level. They hardly ever blow into peoples faces at ground level.

They also aren't controlled by some clot with a lead right foot on the loud pedal. Mostly they fire up and burn efficiently for a reasonable period then stop.

The static MOT test massively understates the amount of pollution when accelerating away from traffic lights or speed bumps.