Car emissions

[Dave Davenport]

Interesting article on the BBC news website; I assumed newer cars were all much cleaner than old ones but that doesn't appear to be the case and it doesn't sound like the current tests are worth a jot when considering what car to buy.
http://www.bbc.co.uk/news/resources/idt-sh/how_toxic_is_your_car_exhaust

 

[classic33]

I'm okay, no car means no emmissions to worry about.

 

[albion]

Survive to 2040, and if we still have Theresa May in charge, then toxic vehicles will not be on sale.

Cough cough.

 

[Dave Davenport]

The current 'lab' tests bare no relation to actual emissions on the road (10+ times as much in some cases), similar cars from different manufacturers can have vastly different levels and some new cars are worse than some 10 year old ones.

 

[Welsh wheels]

The only emissions I produce is when I have baked beans at the cafe stop.

 

[Yellow Saddle]

[QUOTE 5007649, member: 9609"]what a horrible web page - do you have a summary of what the results were.?[/QUOTE]

Basically everything you have heard about old cars being terrible and require scrapping is nonsense. Also, diesel is not as bad as it is nowadays said to be. Nothing is what it seems. All that, with uncertainty approximating that of flipping a coin. I've nominated the story for Ignobel Prize 2018.

 

[Drago]

The current 'lab' tests bare no relation to actual emissions on the road (10+ times as much in some cases), similar cars from different manufacturers can have vastly different levels and some new cars are worse than some 10 year old ones.

Indeed. Currently cars under go a lab test, and the manufacturers know at what rpm etc they'll be tested, so even without defeat devices they still tweak the car and its fuelling to be most efficient at the points of the engines performance where the testing takes place.

Conversely, trucks have gizmos bolted to the exhaust and are tested on a track, so they actually have to drive them. As a result, in the live urban environment, some diesel passenger cars belch out more smog than LGVs do. That's supposed to be changing soon, but I reckon it'll take a back seat to Brexit.

 

[User482]

Basically everything you have heard about old cars being terrible and require scrapping is nonsense. Also, diesel is not as bad as it is nowadays said to be. Nothing is what it seems. All that, with uncertainty approximating that of flipping a coin. I've nominated the story for Ignobel Prize 2018.

Older cars are more polluting than newer cars, and diesel is the dominant source of poor urban air quality.

 

[Drago]

Older cars aren't necessarily more polluting.

A car that lasts 20 years will account for a lot less emission than manufacturing a cleaner replacement at 10 years and shipping it halfway around the planet, and then driving that for another 10.

 

[User482]

Older cars aren't necessarily more polluting.

A car that lasts 20 years will account for a lot less emission than manufacturing a cleaner replacement at 10 years and shipping it halfway around the planet, and then driving that for another 10.

Most of the vehicle's lifecycle emissions occur during the use phase. There are exceptions, for example vehicles doing very low mileages.

 

[Chris S]

From May 2018 cars over 40 years old won't even need to pass an MOT test, let alone emissions test.
https://www.autocar.co.uk/car-news/new-cars/mot-exemption-cars-over-40-years-old-arrives-may-2018

 

[Drago]

Most of the vehicle's lifecycle emissions occur during the use phase. There are exceptions, for example vehicles doing very low mileages.

There are various scenraios which vary with the type andnsize of engine, use, environment etc, but going right back to digging the raw materials out of the ground, thorough to arriving in a showroom floor accounts for emissions equivalent to 30,000-100,000+ miles of actual motoring. That's significant. We're still a very long way from the point where manufacturing a new car and putting it on the road accounts for less lifetime emissions that keeping an older but well maintained car in service.

 

[User482]

There are various scenraios which vary with the type andnsize of engine, use, environment etc, but going right back to digging the raw materials out of the ground, thorough to arriving in a showroom floor accounts for emissions equivalent to 30,000-100,000+ miles of actual motoring. That's significant. We're still a very long way from the point where manufacturing a new car and putting it on the road accounts for less lifetime emissions that keeping an older but well maintained car in service.

If we're talking about scrapping an older car and replacing it with a brand new one, then sure.

 

[presta]

This one only emits a bit of methane from time to time.

 

[User482]

[QUOTE 5007949, member: 9609"]typical car manafacture produces about 20 tonne CO2
if it is emitting 90g co2/km

it would be 140,000 miles before driving it was more damaging than making it, and I doubt many cars get to 140k - so you're right

the thing is though, we get them made in far away lands so most of the pollution is some where else and we can pretend to ourselves how green and caring we are.[/QUOTE]
You're unlikely to find a car with manufacturing emissions that high, and use emissions that low.