House of Commons
Wednesday 17 April 1996
The House met at half-past Nine o'clock
PRAYERS
[Madam Speaker in the Chair]
Air Pollution
Motion made, and Question proposed, That this House do now adjourn.--[Mr. Wells.]
9.34 am
Sir Graham Bright (Luton, South): I am grateful for the opportunity to debate an issue that is close to my heart and one that is causing increasing concern in the country at large: the adverse effect of diesel particulate emissions on health and how we can reduce those levels. I shall stick closely to my notes as it is a fairly technical subject and I have a lot to say about it.
I have a vested interest in the matter: I am, and have been since my early twenties, a severe asthmatic. I am by no means alone in that: more than 3 million adults and 1 million children in Britain today are asthmatics. The proportion of young children with asthma in Britain has almost doubled in the past 20 years. Sadly, each year 40 children and 1,900 adults die as a result of asthma attacks, and more than 100,000 are admitted to hospital. As a chronic disease, it interferes with normal activities, with consequent effects on school, work and lifestyle. Almost all asthmatics require long-term medication--in fact, the total cost of asthma approaches £1 billion a year. Therefore, anything that contributes to that cost must be examined very seriously.
I accept that the evidence from the United Kingdom regarding the potential for air pollution to initiate or exacerbate asthma attacks is questionable--not least because there is no universally accepted definition of asthma for clinical purposes. The inconclusiveness of the current evidence, and thus the need for more research, was highlighted in the recent report issued by the Department of Health committee on the medical effects of air pollution. I recommend that hon. Members examine some of the reports that have been produced on that subject. That report looks specifically at the issue of asthma and of outdoor air pollution.
Many asthmatics perceive that air quality has an adverse effect on their condition. There is some evidence to suggest that air quality can exacerbate asthma even if there seems to be little evidence at present that it provokes the onset. However, the debate is important not only to asthmatics.
As another report from the Committee on Medical Effects of Air Pollutants shows, there is increasing evidence that particulate air pollution has an adverse effect on the health of those who do not suffer from recognised respiratory conditions. Therefore, the debate is of great significance to the whole population, but of
special significance to those who live or work in our cities and large towns, where avoidable particulate levels are at their highest.
Particulate emissions from vehicles are of special concern, as, despite the introduction of new regulations, the Department of the Environment has forecast that their levels will continue to rise into the next decade. That is in marked contrast with the other well-known pollutants from vehicles, such as carbon monoxide and sulphur and nitrogen oxides, which reached their peak between 1990 and 1992 and are now forecast to reduce.
Particulate matter is a complex mixture of organic and inorganic substances. Particulates are known also as black smoke or PM10s--which are simply particles that are smaller than 10 microns in diameter. In general, the smaller the particle, the more likely it is to penetrate the body's defence mechanisms and pass through the delicate tissues to the lungs. Dust from roads and factories are typically larger than 2 microns, but fine particles--such as those present in vehicle emissions--are smaller than 2 microns.
Because of their size, the smaller particles tend to remain suspended in the air for longer than the larger particles, and therefore they are much more likely to be inhaled. The smaller particles, such as those from diesel exhausts, are thus considered to be the most likely to cause respiratory disease and are known to be carcinogenic--we must take on board that very serious point.
Airborne particulates can also interact with other pollutants: the interaction of sulphur dioxide and smoke is well documented. It is therefore included in air quality standards. It is also possible for particles to provide a surface on which pollutants can concentrate, and so have a greater adverse effect when inhaled. Airborne particles provide a surface on which other reactions take place--for example, they can contribute to the formulation of smog.
Some of us will remember the smogs of the 1950s. In 1952, 4,000 people died as a result of smog. Under the then Conservative Government, much pioneering research was undertaken into the effects of air pollution on health, particularly from the combustion of coal. As a result, the Clean Air Act 1956 was passed. For a long time afterwards, it was thought that the problem of urban air pollution had been solved.
Two main factors, however, have combined to make it necessary for us to think again. First, there is increasing evidence that exposure to relatively low levels of airborne particles can increase mortality and morbidity and lead to respiratory difficulties. Secondly, there has been a large increase in volumes of traffic in our urban areas, which has increased particulate air pollution from vehicle emissions.
There have been many studies on the effects on health, most of which have been carried out in the United States. The United States Environmental Protection Agency has shown a correlation between PM10 levels and the number of deaths in some American cities.
Other studies that have been undertaken in the United Kingdom, Greece, Switzerland and the Netherlands add to the evidence that particle levels commonly found in urban areas increase death rates and trigger asthma attacks.
Mr. Ian Bruce (South Dorset):
I have been listening with rapt attention to my hon. Friend, who is obviously an expert in these matters. In referring to people other than asthmatics, is there any evidence to suggest that hay fever is exacerbated by particulates in the air? My family suffers from hay fever, and my wife has a particularly loud sneeze which usually goes off right next to my ear. I would certainly be persuaded to follow my hon. Friend in terms of taking action if it would also help hay fever sufferers.
Sir Graham Bright:
Hay fever is a respiratory disorder. It is obviously related to asthma. Most people believe that hay fever is caused by pollen and grass seeds in the atmosphere. It may also be triggered by other particulates that float about in the atmosphere that we breathe. I am not a medical man, but I believe that hay fever may well be triggered by particulates from exhaust emissions.
None of the studies proves that airborne particle levels are a cause of death, but the weight of medical evidence suggests that health risks occur even at relatively low particle levels. The corollary is that reducing particle levels could have beneficial effects on health. That contention is certainly supported by the Government's Expert Panel on Air Quality Standards.
The World Health Organisation recently revised its air quality guidelines for a series of pollutants, including PM10s. The existing guidelines were originally published in 1987, and were based on an assessment of scientific and medical evidence up to 1985. It is interesting to note that, having reviewed all the data available, the World Health Organisation is unable to recommend a threshold level of airborne particles below which no adverse effects can occur. I regard that as a most serious conclusion, as it shows that all airborne particles are dangerous. We must bear that in mind. It also relates to the intervention by my hon. Friend the Member for South Dorset (Mr. Bruce).
The largest single source of airborne particles in urban areas is road traffic, and within that category the largest component is that derived from diesel exhausts, particularly heavy goods vehicles and buses. Almost all heavy goods vehicles and buses run on diesel. There is also an increasing number of diesel cars. About a quarter of new cars sold have diesel engines.
The most visible result of soot from diesel engines is seen in the form of deposits on urban buildings, but it also permeates clothes and hair. It is estimated that an average bus in London--if there is such a thing--emits 1.5 tonnes of soot every year. As Britain has a total bus fleet of 75,000 buses, 112,500 tonnes of bus exhaust are spewed out every year.
Mr. Ian Bruce:
Most of it seems to end up on my collar.
Sir Graham Bright:
Absolutely.
That is just the tip of the iceberg. When we take into account the number of lorries and taxis, the total amount of soot emitted from diesel engines runs into millions of tonnes a year. In London alone, it costs some £30 million a year to clean up the soot from diesel emissions.
The high particulate emissions from diesel engines are perhaps their main drawback. The second report of the quality of urban air review group, published in 1992, states:
Although, nationally, only 24 per cent. of primary PM10 emissions--that is those released directly into the air--derive from vehicle exhausts--I recognise the point made by the RAC--there are also other causes. If we concentrate on urban levels, however, in 1990 in Greater London, it was estimated that about 86 per cent. by weight of primary PM10 emissions were derived from vehicle exhausts. Therefore, pollution is concentrated where there is traffic in urban areas, but also affects people who live next to major motorways. The M1 passes through my constituency, so air pollution is a cause of concern in the surrounding areas as well as in the town centre.
Other investigations, such as those undertaken by the House of Commons Transport Committee in 1993, provided evidence that much higher levels--up to 96 per cent.--of black smoke emissions derive from road transport in cities such as London, compared with 46 per cent. in the entire United Kingdom.
It is important to consider the subject in respect of local concentrations of particles and their cause, rather than simply looking at the overall figures. In most of our urban areas, PM10 levels are very high. In addition, the vast majority derive from diesel exhausts from medium and heavy goods vehicles and buses--up to 76 per cent. is cited in the Transport Committee report of 1993.
At this point, I hasten to add that there is no reason to be anti-road transport. As I represent Luton, where motor cars are manufactured, I do not want to be anti-road transport, and I am sure that few hon. Members are anti-bus, especially in urban areas. It is important, however, for us to find ways to reduce the problem of pollution caused by buses, so that the full environmental benefits of encouraging more travel by bus can be realised.
It is also reasonable to expect those who develop and operate road transport fleets increasingly to recognise their environmental responsibilities. It is right for the Government to conclude that, because of the high mileage they travel in urban areas, operators of lorries, taxis and buses have a special responsibility to ensure that their vehicle comply with the vehicle emission standards.
It is obvious that bus operators already recognise that: a recent spot check in London revealed that just 8 per cent. of buses were found to be over the current legal exhaust emission level. I congratulate them on that. There is also a lesson for other vehicle operators, as many lorries that pass this building belch out black fumes. Obviously the emissions from buses are much lower than those from other diesel-powered vehicles.
Successive Conservative Governments have an exemplary record in respect of legislation to improve air quality, and the present Government are no exception. I was pleased to be associated with the campaign that led to the Government's decision to insist on stricter controls on emissions from petrol-driven cars compared with those originally proposed by the European Community, which
required all new cars to be fitted with a catalytic converter. In fact, I raised that matter in an Adjournment debate.
As a result of that legislation, nearly 5 million cars on UK roads are fitted with catalytic converters. We also have a baseline threshold for known air pollutants, based on state-of-the-art medical and scientific knowledge. With the measures already introduced, the UK confidently expects to meet its existing international commitments for reductions in nitrogen dioxide and sulphur dioxide.
Further technological advances, such as fast-action catalysts and super-efficient engines, will reduce emissions from petrol-driven cars even further, and much research into that aspect is being undertaken by the main car manufacturers--none more so than Vauxhall, which is located in my constituency.
The Government lead the field, and there can be no doubt of their commitment to ensuring improved air quality. The Government's sustainable air strategy identified urban air quality as one of the key changes to UK environmental policy. That strategy also made it clear that improving air quality depends above all on improvements in the transport sector, and an action plan of two transport-related measures was proposed.
The Government also responded positively to two reports published in November 1995 by the Committee on the Medical Effects of Air Pollutants and the Expert Panel on Air Quality Standards, by laying down strict air quality standards for PM10s in the UK. The expert panel was established following the Government's commitment in the 1991 White Paper, "This Common Inheritance".
The Government have accepted as a benchmark for policy an average daily concentration of 50g/m 3 , which I understand is the equivalent of inhaling not more than 1 mg in 24 hours--quite a calculation. Diesel engines, in common with petrol engine, also emit carbon monoxide, hydrocarbons and nitrogen oxide. Carbon monoxide and hydrocarbons, which cause the characteristic diesel smell, can be easily removed by an oxidation catalyst.
A much smaller percentage of diesel engines compared with petrol engines are currently fitted with catalysts, which perfectly illustrates a particular problem with diesel vehicles. It is not uncommon for diesel-powered vehicles, by contrast with petrol engines, to be kept in use for many years. That is particularly true of buses.
There are about 75,000 single-decker and double-decker buses in the UK seating 17 or more passengers. Of those vehicles, 57 per cent. are more than 10 years old, but 40 per cent. are more than 24 years old. The majority of buses in use today are extremely old vehicles that were built at a time when emission controls were not a high priority. A major trial in London launched in January by my right hon. Friend the Secretary of State for Transport must be wholeheartedly welcomed. The trial will involve about 7,000 London buses running on reduced or low sulphur diesel, and some will be fitted with oxidation catalysts. That is good news, but it does not address the problem of particle emission from buses, taxis and lorries.
The progress made with legislation to reduce emissions from heavy goods vehicles in the form of European Union directives 1 and 2 is also welcome, and will be fully effective in respect of vehicles of more than 7.5 tonnes from October. It will bring the emission limits for new
diesel vehicles in line with the stringent standards that were introduced in the USA in 1994, and will set a limit on particulates for the first time.
However, I emphasise that the limit is still far too high, as evidence from health studies shows. We should aim at a much lower limit. The new limit will apply only to new vehicles, so, because of the long service to which many vehicles are subject, it will be many years before the limit becomes fully effective. For that reason, there is a strong case for the Government to act to encourage the retrofitting to all diesel vehicles of oxidation catalysts and devices to control particulates.
The unique challenge in controlling diesel emissions is that of removing particulates. The only effective way is filtration. Particulate filters, or traps, are known to be highly effective in reducing PM10 levels from diesel exhausts by as much as 90 per cent.--which makes them an effective piece of equipment. Several mechanisms have been developed, but the problem with any conventional filtration device is that it soon clogs and needs replacing, or the soot must be removed by high-temperature combustion. It is not reasonable to expect that to be done on a large scale, because of the practical difficulties and cost.
A much more interesting development in filtration technology is the so-called continuously regenerating trap, or CRT, which was developed in the UK by Johnson Matthey. The CRT works by an ingenious combination of catalyst and filter technology, to remove particulates as well as carbon monoxide and hydrocarbons, which give the characteristic diesel smell. The device comprises two chambers, which can be engineered to provide sufficient sound deadening to replace the conventional silencer and be mounted in its place.
A conventional oxidation catalyst is located in the first chamber, which ensures among other things maximisation of the oxidation of nitrogen monoxide to nitrogen dioxide. The second chamber contains a second filter that traps the particulate matter, which is mostly soot or carbon. The carbon reacts with the nitrogen dioxide to form carbon dioxide and nitrogen--both of which are then emitted as gases. Not only does the filter continuously clean itself, so that it does not need separate cleaning or replacing, but the process reduces the amount of nitrogen oxide.
I had the pleasure of observing the effects of the CRT by comparison with a conventional exhaust system fitted by Johnson Matthey to a 16-year-old Bristol VTR bus, which already had 2.3 million miles on the clock. The results were amazing. When the bus was run, the conventional exhaust system produced black smoke and the smell normally associated with diesel engines. When the bus was switched to the CRT system, the smoke and smell immediately disappeared. If one places a white handkerchief, as I did, over the exhaust outlet, it stays white--so we know that the technology works.
The CRT can be fitted to any turbocharged diesel engine. It is estimated that about half the buses in use today are fitted with such engines. Unfortunately, as many of the old Routemasters used in London were fitted with normally aspirated engines, they are not suitable for retrofitting. It is thought that about 20 per cent. of London's current bus fleet could be fitted with CRTs immediately.
As a minimum, I should like CRTs fitted to every new heavy goods vehicle, bus and taxi--and eventually to diesel cars. Even vehicles that are not suitable for CRT
could benefit from an oxidation catalyst, which remove some particulates as well as most of the carbon monoxide and hydrocarbons, which cause the diesel smell. That improvement would come as a relief to many people.
It is often suggested that retrofitting heavy goods vehicles with emission control devices would be prohibitively expensive. In fact, for a large lorry or bus, it would cost about £3,500, and considerably less for smaller vehicles. As a stab in dark, I assume that the cost for a smaller car or taxi would be £700 or £800. CRTs would be a reasonable and affordable suggestion for all urban-based heavy goods vehicles, taxis and buses, and they should be retrofitted.
There is no doubt that the balance of costs and benefits will make retrofitting even more attractive in the future. The more people that call for CRTs to be fitted, the cheaper they will become, just as happened with catalysts on motor cars. I suggest that the potential benefits for urban air quality would justify fiscal measures to encourage CRT use.
Several trials are being undertaken in which CRTs are fitted on commercial buses. In spring last year, Oxford City Buses started using 20 new Dennis buses fitted with CRTs. As many will be aware, Oxford is one of the cities that has pioneered the increased use of mass passenger transport to reduce car use, so the decision to trial CRT there is obviously especially important.
As an example of CRT being retrofitted to buses, Manchester North Western retrofitted CRT, in December last year, to two of its buses operating in Warrington. I am sure that the House will also be pleased to know that the Conservative-controlled Westminster city council wrote vehicle emission limits into its recently awarded contract for refuse collection. As a result, the company undertaking the contract is fitting CRTs to all its vehicles. We see dustcarts belching out fumes as they compact the trash, and it is nice to know that they will no longer blow out soot in Westminster.
What can be done here in Westminster could be done all over the country. I suggest that fiscal measures should be introduced to encourage that to happen. Those are some of the examples of the use of CRT fitted to heavy good vehicles to the benefit of the urban environment.
The only real barrier at present to CRT is that, in common with all catalytic systems, it needs very low sulphur diesel to work. I appreciate that new EC legislation will lead to lower sulphur fuels being introduced in October this year. I congratulate Shell on having already introduced them. That is good, and should be encouraged. Obviously, compliance with Euro 2 particulate emission limits will reduce sulphur particulates, but the EC limit is well above that in place in Sweden, where very low sulphur diesel--or so-called city diesel--which contains less than 50 parts per million sulphur, is now the norm.
City diesel is available in the United Kingdom, but, because it is not a requirement, the outlets are far too sparse for most practical purposes. The company Greenergy should be congratulated on its initiative in supplying very low sulphur diesel in the UK, as should Sainsbury's on its efforts to increase the use of Greenergy low sulphur diesel from several of its hypermarket fuel outlets.
I accept that it may be possible, with further research, to develop a particulate trap system that does not require such low sulphur fuel, and that should be encouraged. But it is galling to think that we could have benefited from the use of such devices now if low sulphur fuel was more freely available.
I have been talking about ways of reducing the particulate emission from existing diesel engines and thus obtaining an immediate improvement in urban air quality. It is also important, however, to consider other ways in which the problem of particulate emission can be tackled in the longer term.
Without doubt, some of the cleanest fuels that could be used in buses and other commercial vehicles are liquid petroleum gas, or LPG, and compressed natural gas, or CNG. LPG and CNG emit almost no particulate matter, and would be ideal fuels for use in commercial vehicles in towns and cities. Bus companies, in particular, should be encouraged to convert or replace their fleets with vehicles able to use LPG, and they should be provided with incentives to do so. That is especially important, because nil particulate matter comes out of the exhaust when LPG is used.
I await with interest the results, due some time this year, of the trials that have been set up under the Government research project on alternative fuels. Those include trials on the use of LPG, CNG, biodiesel, city diesel, electric vehicles and hybrid vehicles, such as electric-diesel and electric-petrol. Trials are being carried out all over the United Kingdom, many on commercial vehicles. In the long term, those trials could lead to vehicle developments that virtually eliminate urban particulate pollution. In the meantime, however, the problem of what to do with vehicles currently in use will remain.
As an asthmatic, I welcome the fact that the Government recognise the need to take action to reduce airborne particulate pollution, especially in urban areas, and that much legislation has been passed to ensure that. However, because of the seriousness of the problem and the nature of its cause, I do not believe that we can just sit back and wait for the effects of legislation to work through. There is increasing evidence that improving urban air quality represents one of the major future challenges to human health. We have the technology to take a quantum leap in improving urban air quality by reducing particulate emission from vehicles in use now.
I urge the Government to take whatever fiscal and legislative measures are necessary to ensure that. Differential taxing of low sulphur diesel would encourage the fitting of catalytic converters and continuous regenerating traps to all vehicles, just as it encouraged the use of unleaded petrol. Differential taxation also already exists for natural gas, and should be extended to LPG.
"the impact of diesel emissions on urban air quality is a serious one. Any increase in the proportion of diesel vehicles on our urban streets is to be viewed with considerable concern unless the problem of particulate matter and nitrogen oxide emissions are effectively addressed."
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