London (and other) buses

Aquila

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Aquila
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When I recently visited London I was shocked by what seemed like a significant increase in air pollution from the last time I visited. I have been living in the U.S. for many years and was just knocked over by the smell of diesel fumes coming from London's buses, taxis and lorries.

I know that mayor Ken Livingstone has been trying to get people to drive less in central London, setting up congestion zones with fines, and encouraging people to use public transport instead of cars, but has anyone actually done any research on whether this is really helping to reduce air pollution and carbon emissions?

It seems to me, that the added number of buses in London are actually making the air worse, because diesel fumes from buses, taxis and lorries (and the occasional Mercedes) contains what seems like far more toxic substances than plain old passenger car exhaust. The diesel fumes smell as though they have sulfur in them and give me a far worse headache than regular benzene. I would actually prefer to breathe in fumes from 20 or 30 cars instead of one double-decker or bendy bus.

Are we actually making the air worse by adding more buses and diesel vehicles?
 
London pollution is among the worst in Europe. It was expected that the congestion charging plan would result in increased diesel emissions due to increased bus use. Early on, it was believed that improvements in emissions standards would mostly offset the increased number of diesel vehicles (see 2004 emissions report here – pdf). That hasn't quite panned out, and a plan for lowered diesel emissions goes into effect in London in February.

The Low Emission Zone is an area covering most of Greater London, within which the most polluting diesel-engined vehicles are required to meet specific emissions standards. If they do not, they will need to pay a daily charge.

 Operators of relevant vehicles that do not meet the emissions standards have several options available to them. They can:
  • Buy a newer vehicle that meets the required emissions standards.
  • Re-organise their fleet for journeys within the Zone.
  • Modify their vehicles to meet the required standards.
  • Pay the daily charge.
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The Low Emission Zone (LEZ) will start on 4 February 2008 and will apply 24 hours a day, every day of the year. It will affect diesel-engined lorries over 12 tonnes in weight.

From July 2008, it will also apply to all lorries over 3.5 tonnes, in addition to buses and coaches. http://www.tfl.gov.uk/roadusers/lez/default.aspx
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Does anyone know if bus diesel is any different to normal-car diesel? In the UK, there are many diesel-powered normal-sized cars (ours is one of them), but I agree that bus fumes do seem to be more noxious. Or is it just because a bus exhaust is far larger and belches out more fumes?
 
tkingdoll said:
Does anyone know if bus diesel is any different to normal-car diesel? In the UK, there are many diesel-powered normal-sized cars (ours is one of them), but I agree that bus fumes do seem to be more noxious. Or is it just because a bus exhaust is far larger and belches out more fumes?
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I thought that it was because the buses are older and the engines in worse condition than most cars.

In Liverpool where I grew up, before the buses were deregulated by the Conservative Government in the 1980s, the bus fleet was replaced fairly regularly and no buses were more than about 5 years old.
The transport infrastructure was viewed as an essential SERVICE and did not necessarily need to run at a profit.

After deregulation the various companies who took the place of the local transport authority obviously have to run their bus 'services' as businesses which means that, as well as not operating the less profitable bus routes, the buses in their fleets are kept running long past the point at which they should be scrapped and the emissions they cause have dramatically increased. HUZZAH!!! Another victory for capitalism and the free market!!! :boggled:

London has a different problem - London Transport was never deregulated (for some reason Thatcher thought that market forces should not be brought to bear on London's buses :rolleyes:) but the buses in London are the ancient routemaster buses which should have been pensioned off years ago. The older the diesel engine, the worse the pollution, in general.
 
Jimcalagon said:
the buses in London are the ancient routemaster buses which should have been pensioned off years ago.
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As far as I'm aware, with the exception of a couple of tourist routes the Routemaster buses have been pensioned off for the last couple of years - still too late, mind, and there's no guarantee that the replacement buses are going to be paragons of maintenance.
 
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richardm said:
As far as I'm aware, with the exception of a couple of tourist routes the Routemaster buses have been pensioned off for the last couple of years - still too late, mind, and there's no guarantee that the replacement buses are going to be paragons of maintenance.
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Fair enough - the last time I was in London was about 2001 so a lot might have changed since then.

I forgot to add - my brother-in-law is a mechanic for one of the major bus operators on Merseyside and some of the stories he tells me about the state of the buses they use (and the drivers) are eye-opening. I can only compare it with the bus services in the Isle of Man where I now live which are operated by the government as a not-for-profit service to see the horrible effects of deregulation in the UK.
 
I think it's the grade of fuel. Diesel has different formulations, cheaper = stinkier. Diesel here in California costs more than premium gasoline, but doesn't smell any worse- either at the pump or at the exhaust pipe.
 
casebro said:
I think it's the grade of fuel. Diesel has different formulations, cheaper = stinkier. Diesel here in California costs more than premium gasoline, but doesn't smell any worse- either at the pump or at the exhaust pipe.
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I'm not a mechanic but I was led to believe (having previously owned a diesel car) that if you let the fuel tank run very low or dry that the crud at the bottom of the tank is drawn into the system - this is supposedly a much worse thing for diesel engines than petrol engines and is what causes the thick clouds of black smoke seen issuing from the exhausts of Britain's buses.

Can anyone confirm this?
 
Jimcalagon said:
I'm not a mechanic but I was led to believe (having previously owned a diesel car) that if you let the fuel tank run very low or dry that the crud at the bottom of the tank is drawn into the system - this is supposedly a much worse thing for diesel engines than petrol engines and is what causes the thick clouds of black smoke seen issuing from the exhausts of Britain's buses.

Can anyone confirm this?
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No what causes the excess smoke is over fueling, this occurs at full throttle. this can be caused by several factors; poor maintenance, being a common reason for excess black smoke. Blocked air filters not letting enough air into the engine produce an overly rich mixture which produces the black smoke.

Also you may have noticed that many turbo diesel cars produce significant black smoke when the turbo kicks in, this however is by design. extra fuel is dumped in to produce the extra power.

Modern computer controlled engines do not suffer from this as much as older generation Turbo diesels, I suspect most buses use very old technology however.

Simon.
 
This is an article on the health effects of diesel exhaust:

http://en.wikipedia.org/wiki/Diesel_Particulate_Matter

I sometimes wonder if my mum's heart disease is linked to the air she is forced to breathe while shopping. She doesn't smoke, and eats very healthily.

I also get very annoyed when I see truck/lorry, taxi or bus drivers just running thier engines while they eat lunch, take a nap, or just listen to the radio, often in a residential area (both in England or the U.S.). I sometimes approach them saying I'm from the "neighborhood environmental watch" or something similar and ask them to please turn their engine off.
 
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