Government petition condeming diesel car penalties.

[EastPete]

As a scientist who has worked in the pharmaceutical industry for 35 years in the area of drug safety, toxicology and 'risk assessment', I have been following this thread with interest. Unfortunately, the majority of what is reported in the media and on the web, regarding pollution and health effects, does not present the research data in a scientifically correct manner, and the interpretation is often misleading. There is a fundamental misunderstanding in the media and public at large of the difference between hazard and risk - the two are often confused. Hazard is the potential for something to cause harm. Risk is the likelihood of it causing harm under a given set of circumstances. So, for example, some scientists do an experiment where they force rats to breathe in diesel engine fumes for 6 hours/day for 2 years. This causes all sorts of nasty effects in the rats - early death, increased cancers and lung damage. This shows that diesel fumes are potentially hazardous, but this was only shown under extreme conditions and high exposure levels in the laboratory. It tells us nothing about the risk of similar effects being observed in humans going about their normal daily business. To quantify the risk to humans, modelling of the rat data needs to take place to predict what the human risks are. You can do this every simplistically - measure the diesel fume exposure (PM 2.5s, PM 10s or nitrous oxide or whatever) in the human environment (obviously this is very variable, but researchers may choose to do this at traffic black spots where they will get 'worst-case' readings), and calculate the relative exposure to that which killed the rats. Say it was 1000 times less than in the rats- they then do population modelling to predict how people they believe diesel fumes (or any other pollutant) might kill a year at that exposure level.

I am probably doing the researchers a slight disservice here, because their models are probably a bit more elegant than I have described here, but the basic principle is the same. The key is the 'exposure' i.e.: level of pollutant we are exposed to, and how risk is calculated from high level exposure data generated in the laboratory. There are many assumptions and variables involved - rats do not always predict human responses very well, and many pollutants act only above a certain threshold- in other words, many humans can tolerate low level exposures without harm, because the body deals with it -only at higher levels will heatlh effects be seen. One of the basic laws of risk assessment and toxicology is that everything is a poison - it is only the dose that distinguishes between the material being harmful or not. Water is toxic if you drink too much of it. This is why I cringe every time I see a journalist on TV asking a scientist/government minister ' is it safe ??' - nothing is safe - everything can cause harm if you get too much of it under the wrong circumstances.

As human beings, we all have an impact on the environment, since we are consumers of energy, food, earth's raw materials to live our modern lives. I think the retrospective punishment of diesels is unfair - I am probably biased since I own two diesel cars. I agree that use of diesel cars for short journeys in cities is probably not a good thing, but of course the heaviest vehicle pollution in cities probably comes from working vehicles - buses and delivery vans/trucks. Modern diesel technology has drastically the emissions of concern - particulates and nitrous oxide - at the cost of reducing engine efficiency, thereby increasing CO2. Hybrid and electric vehicles make a lot of sense for improving air quality in cities, but for the 90 per cent of us who live outside the capital cities, with little public transport and longer distances to travel to work or for recreation, a diesel car makes a lot of sense with the better fuel economy and the longevity of the diesel engine. I think we are doing our bit for the environment by keeping older cars such as the 75 well maintained and on the road - I think I read somewhere that 40 per cent of the energy a car uses in its lifetime is during its manufacture, so making cars last longer would help reduce pollution and the environment. This, of course, does not suite h vested interest of the car industry, who want us to throw our cars away after 7 years and buy a new one, nor the politicians who want economic growth and tax income from new car registrations.

I do worry about the possible toxic effects of all the batteries in the hybrid/electric cars when they come to be disposed of - they are a very fine cocktail of some of the most toxic heavy metals on the planet - you want to keep them out of the ground water and soil, if we wan to avoid potential health effects for future generations.

The frustrating problem with all these discussions/debates is trying to find your way through all the vested interested and zealous political and environment ideologies - the truth is in there somewhere, but we do not really know where it is or how to get at it - we often just get fed the two extremes of the argument.

In summary, there are 'pros' and 'cons' to everything, and we are not good at assessing real risk - often, it is easier just to ban it or tax it.

I'll get off my soapbox now, but look forward to any responses. I'll put my full credentials on the bottom here, so you can decide which bodily orifice I might be talking out of !

Cheers

Pete
BSc (Hons), PhD, DipRCPath (Tox), FRCPath.

[wraymond]

Thanks for that EastPete, very interesting. Good to have a balanced and measured explanation.

[EastPete]

We can have all the cleverest, most innovative technology in the world (hybrids cars, hydrogen fuel cells etc.), but it will only scratch the surface against the growth of the world's population and the increasing affluence and consumerism in the developing countries, with increasing car ownership. We can already see what has happened in China with the switch from bicycles to cars in Beijing and the horrendous air pollution that has resulted. The world economies run on consumerism and consumption, and I cannot see that changing.

Buying a hydrid or electric car in Britain and thinking you are really helping the planet, is a bit naive, but I guess it makes the owners feel better about themselves (didn't somebody suggest the Toyota Pruis should be called the Toyota Pious ?). I do not want to knock these new technologies too much - they are all very fine pieces of engineering but like everything in life, they have their pros and cons (and we taxpayers are subsidising every new electric car to the tune of 5000 pounds !).


My own industry (pharmaceuticals) could be partly to blame here - we have been quite good at producing vaccines and drugs so that people do not die of infectious diseases, AIDS etc. , thereby increasing longevity and world population. Perhaps we should let nature take its course, and let diseases such as Ebola etc. exert some population control, but of course, that would be unethical and inhumane, and all too easy to say from the comfort of pestilence-free middle England !

Pete

[mikesmith2]

Signed as well

[rathlindri]

Signed, thanks for doing this

[Phil th Barrow]

Originally Posted by Rickoshea

Roverite,

I fear you are still perpetuating untruths. Firstly, I suspect the only informed decision made by those in diesel cars was to save money both in terms of fuel costs and taxation. It might produce less CO2 but this is not a pollutant, it is a natural by-product of life on earth. The down side is they produce lots of very nasty NO2 and particulates. No amount of euro 5, 6, 7 or 8 will alter the basic physics of burning this dreadful stuff in anything less than optimal conditions i.e ships, trains, and long distant lorries.

I did consider diesel as I did when I bought our 75 in 2001! Always came to the same conclusion that they are wrong for stop start motoring and lots of short journeys. Rational eco decision is get a petrol! We live in Greater London and this means we get free use of the trains, underground and busses so our annual expenditure on petrol is around £1,000.

Interesting you mention housing! To prove my green credentials, we live in a 4 bed detached house with solid walls and was very expensive to heat. I realised that in retirement and therefore at home a lot of the time, lady wife would probably not put up with my old excuse that cold is good for you. I have therefore insulated the house with external insulation as well a stuffing the roof with over a foot of fibreglass. Also installed a new gas boiler. The house has moved from an energy rating of G, the worst to B - second best!. Better still the annual combined gas and electricity bill is around £750 which is not bad for a 2,000 square foot detached house set on a hill inhabited 7 days per week! Better still, I installed PV panels when the government introduced FIT (Feed In Tariffs). We get paid for very KWH we produce and the annual income from our 3 kilowatt array is £1,600 a year that is tax free and index limited and guaranteed for the next 22 years! This ensures that our total energy costs of minus £850 pa!

I agree with you that those in energy inefficient houses should be stuffed by the tax system and perhaps you would like to share your green credentials with us. (having a diesel is a negative!)

Hi,

Re cavity insulation. This only is my opinion after been in th building industry for 15 years up to 1992 and there for should be taken as so. Cavity walls were created to give a barrier between th inside and out side elements.
This 2 inch gap enables th walls to breath via air vent's and th loft. In th 80's on site we were given "none absorbent material" to be put in th cavity's as insulation. We soon made good use of this by immersing this material in th water butt and made snow balls from it to throw at each other.!!!

I also have 2 neighbours that have had there cavity's filled in th vain attempt to cut heating costs..... 2 years latter both have damp under bays, behind cupboards and on window reveals ect. A wet house is a cold house and it cost's a lot too heat this un healthy environment.

If I where forced by government to improve my heat loss I would dryline th internal walls that heat sink to th out side with insulated plaster board. Yes this robs you of a small amount of internal space but save's your health house and home.


My Conclusion... Government ideas are not always for our benefit.

Ps, As we speak my outside relative humidity 79% my inside RH 39%

Pss, Pull a washing machine out in your utility and have a look at th bare plaster behind... Enough said.

Thanks for listening.

Phil th Barra.

[Rickoshea]

Who mentioned cavity walls?

I said we had solid (brick) walls and the house used to be a cold as a witch's mammary glands in a tin bra. Internal insulation both shrinks the internal space (as you mention) and is hugely disruptive to install. It is also not very efficient with too much cold bridging and not much insulation. Insulation on the outside involves no disruption to the household (other than making the builders tea). Because you have no depth limits you can slap 4" of insulation for stunning reductions in heat loss. Better still the Dew Point is very close to the outside of the insulation so absolutely no chance of condensation inside the house walls. The best thing about external insulation however is the solid brick wall acts as a heat store.

It you are planning insulation then always install on the outside! Anything else is a poor lash up.

[Phil th Barrow]

Originally Posted by Rickoshea

Who mentioned cavity walls?

I said we had solid (brick) walls and the house used to be a cold as a witch's mammary glands in a tin bra. Internal insulation both shrinks the internal space (as you mention) and is hugely disruptive to install. It is also not very efficient with too much cold bridging and not much insulation. Insulation on the outside involves no disruption to the household (other than making the builders tea). Because you have no depth limits you can slap 4" of insulation for stunning reductions in heat loss. Better still the Dew Point is very close to the outside of the insulation so absolutely no chance of condensation inside the house walls. The best thing about external insulation however is the solid brick wall acts as a heat store.

It you are planning insulation then always install on the outside! Anything else is a poor lash up.

As I don't wont to hi jack any more th good work of Roverite who as spent a lot of time and energy (not for profit) into this very interesting discussion for th benefit of others..

Soooo i'Il just say in my opinion only that I disagree to th idea of heating cold wet walls. Heat only th space you use. Simples.

[Rickoshea]

I fear you are missing a few points about insulation. The first is that as long as the temperature outside your house is colder than the inside then the heat you are spending money creating will leak out. The walls of your house will provide the largest area through which this heat can escape, therefore the more you can do to reduce this loss, the less you will need to spending heating your home. Having an inch of insulation on the inside, will allow your expensive heat to escape at least twice as fast as with 4 inches on the outside and if you allow for the cold bridging that is a part of internal insulation, you should expect 3 times the loss.

With external insulation, you cannot have damp walls (unless you have rising damp or defective roof) as the dew point is inches from the wall and storing heat in the wall is good as they can hold so much heat (unlike air). You can therefore run you boiler at max efficiency (assuming it is a condensing boiler) to heat the house and the walls. This heat in the walls will find if VERY difficult to bridge 4 inches of foam so the heat in the walls can be transferred back into the house.

As 2 retired people living in the house full time and with a wife who likes in warm, we have our boiler on for 2 hours in the morning and 6 at night. The minimum temperature in out house (in the hall) when the heating goes off is 19.5c. Seven hours later, when the heating goes on, it has dropped a max of 2 degrees during the cold weather.

Our gas bill for a 4 bed detached house on a hill of about 1,700 square feet is less that £600 pa and that includes hot water and cooking.

Internal insulation is a lash up and I speak from experience here!

[SD1too]

Originally Posted by Rickoshea

The walls of your house will provide the largest area through which this heat can escape ...

The largest area perhaps, but you have omitted to mention the U-value which may reveal that the greatest heat loss is not through the walls at all.

However, you are straying into territory which has nothing whatever to do with cars or the subject of this thread, and I feel the presence of a displeased moderator.

Simon