Introduction
Pollution
    Carbon oxides
    Volatile organic compounds (VOCs)
     Nitrogen oxides (NO_xs)
    Heavy hydrocarbons
    Sulfur compounds
    Particulate matter from exhausts
    Particulate matter from friction between tyres and road surfaces
    Lead compounds
Environmentally-acceptable cars
    Conventional cars
    Electric cars
    Petrol-electric hybrid cars
    Vegetable oil cars
Cars of the future
Reduction of consumption
Conclusion

Introduction

Without doubt, light road vehicles are a major source of pollution today. These include the pick-ups and 4x4s, so beloved by Cypriots.

Recent reports have shown that about 60,000 vehicles have not undergone mandatory MoT testing. It can be assumed that this is not because of the £25 fee, but because the owners know that they haven't a chance of passing. Many of them can be seen on the roads, spewing clouds of smoke from their exhaust pipes. This is certainly increasing local pollution levels and could be stopped overnight by strong action.

However, this is only a small part of the problem. There are seven types of polluting emissions coming from cars, even as they are driven away from the showroom, with a eighth type on cars which burn petrol containing lead (the sale of which has become very restricted since May 2004):

As a general rule, the larger the car, the higher is the amount of pollution produced. For this reason, I suggest that, for passenger use, it is unnecessary to have cars with engines larger than, say, 2 litres capacity in a country where the speed limit on motorways is 100 km/h and where one can drive from one side of the island to the other in less than two hours.

Petrol or diesel?

In my opinion, only petrol-driven cars with a catalytic converter should be used for passenger use. It is true that diesel-engined cars consume less fuel per 100 km than their petrol-driven counterparts, of equivalent power. However, this is no advantage in terms of pollution. The amount of carbon in diesel fuel is much higher than in the more volatile petrol, so that the carbon dioxide produced is substantially equal (typically 150 - 450 g eq. C/km, depending on engine size and other factors). All the other of the first six pollutants in the above list are higher with diesels than with petrol-engined vehicles fitted with a catalytic converter, even if the diesel burns desulfurised fuel.

That having been said, some of the latest diesel engines have become less polluting, provided they are correctly maintained. However, the advantage of this is reduced as the wear on the engine components increases, typically after having run 75,000 - 100,000 km.

The big advantage of diesel cars used to be the very considerably lower cost of diesel fuel. However, this advantage has diminished and is expected to do so even more in the future. In many EU countries, the cost of diesel fuel is either the same as petrol or even higher, in attempts to reduce pollution. As diesel engines are larger for a given power production than petrol ones, under the new car tax regime, owners of diesel cars with a given performance level will pay more for this, and insurance, than would their petrol-burning counterparts.

Conventional or 4-WD?

A decade or so ago, 4-WD cars were useful, because there were many dirt roads in Cyprus. Today, most roads have a hard surface. The 4-WD therefore has lost its main raison d'être. I address a question to owners of 4-WD vehicles: when was the last time that having all-round traction allowed you to get out of a difficulty that would have been impossible with a conventional passenger car? I wouldn't mind betting that a large majority of non-agricultural owners, if they were honest, would answer years ago. Even the forest roads are negotiable with conventional cars. So, why have this feature which adds heavily to the cost of a car and adds to the weight and therefore the fuel consumption?

Catalytic converter?

What is a converter? Such a system meters some air into the exhaust gases before they go into the converter. This is a container containing thousand of ceramic beads, each coated with a microscopically thin layer of platinum. As the hot exhaust gases hit the platinum, the latter reacts chemically with them, without being consumed, and this reaction is what is called exothermic, which means that the temperature rises. In fact, it reaches a bright red heat and this allows any residual combustible material in the gases to be burnt. The result is considerably reduced emissions of carbon monoxide, VOCs, NO_xs, heavy hydrocarbons, sulfur compounds, etc., all of them pollutants. It should be noted that converters do not reduce carbon dioxide emissions, another pollutant.

There is one proviso with converters; if leaded petrol is used, even in minute quantities, the platinum becomes "poisoned". One tankful of leaded petrol will stop a converter from working, for ever. It is quite an expensive component to replace, but this cost would have to be borne by the careless motorist, because the MoT test will reveal the problem. It is for this reason that the filler tubes of cars with converters have a diaphragm which will not allow the filling nozzle of a leaded petrol pump to enter.

Diesel cars cannot be fitted with catalytic converters and this is one of the reasons why they are more polluting.

Pollution

Let's have a look at the pollutants in the above list.

Carbon oxides

Carbon dioxide is the major cause of global climate change (see the essay on Climate change). Cyprus has a legal obligation to minimise emissions of carbon dioxide. Reducing these may involve:

Carbon monoxide, which is a highly toxic gas causing semi-chronic cumulative damage to the oxygen-carrying capacity of the blood, oxidises in the air to carbon dioxide within a day or two, depending on the abundance of hydroxyl radicals.

Volatile organic compounds (VOCs)

VOCs are organic gases or vapours. Typically, in this context, they are vapours or decomposition products derived from unburnt or partially burnt fuel. Their effect is essentially local and they are a component, along with NO_xs, of the smog, haze and ozone that affects most towns, especially in summer. Anyone approaching Nicosia from the south on a hot summer's afternoon will have seen the pall of pollution over the city and blocking the view of the Pentadaktylos mountains to the north. This is largely due to motor traffic. The mechanism is a chemical reaction between the VOCs and the NO_xs, triggered by sunlight. The resultant reaction is also the precursor of a second photochemical one, which produces ozone, a highly toxic and irritant gas when it is at ground level. It requires only trace amounts to cause a reduction of immune system responses and this is the probable cause of a number of diseases, including asthma in children.

There are some natural producers of VOCs, such as terpenes and terpenoids emitted by a few aromatic plant species. The quantities in cities from these sources are negligible. On the other hand, in forested areas, natural VOCs may approach similar levels to those produced by vehicles.

Nitrogen oxides (NO_xs)

There are several different kinds of nitrogen oxides. The only normal major natural source is the reaction between the nitrogen and oxygen due to the heating effect of lightning strikes. Most of this is immediately washed out by rain. All combustion at temperatures exceeding about 500°C will produce NO_xs and that in the cylinders of a car engine is no exception. This is the other component, with VOCs, required to produce smog, haze and ozone, especially in cities (see the preceding section).

Heavy hydrocarbons

This is a phenomenon normally associated principally with diesel engines, although it does occur, to a small extent, in petrol engines, especially if badly maintained. Unburnt fuel, in contact with the cooled cylinder walls, and oil which passes the piston rings and valve guides, often undergoes a number of reactions because of the heat and pressure. These often produce polymers of the alkane groups and other heavy hydrocarbons, as well as VOCs. Many of these heavy molecules are dangerous to lung tissue and some may even be carcinogenic (causing cancers). Even if you cannot see exhaust gases, these heavy hydrocarbons are inevitably produced. If the exhaust is actually visible, then the problem is severe.

Sulfur compounds

All fossil fuels contain sulfur compounds. These are mostly removed during refining, especially the specially desulfurised fuels, but there is always a small proportion remaining. These produce sulfur dioxide during combustion and this oxidises in the air to form sulfur trioxide. This combines with humidity to form sulfuric acid, a major component of "acid rain". This can cause various illnesses in plant and animal life, including a contribution to emphysema and asthma in humans. It also causes attack of the surfaces of marble and limestone (e.g., the problems with the Parthenon in Athens) and, when it does so, it releases carbon dioxide, increasing the atmospheric loading. It is also believed that sulfuric acid, resulting from the combustion of fossil fuels, was a major contributor to the deaths of some 4,000 persons during the smog in London in December 1952

Particulate matter from exhausts

All vehicles emit particulate matter, such as tarry soots. These have been identified as probable carcinogens (similar to those produced by cigarette smoking). With cars fitted with catalytic converters, most of this particulate matter, with a well maintained engine, is burnt, except that the converter does not start to work until it becomes hot, usually after 5 or 6 km after starting from cold. This is also when the engine runs "rich" (i.e., with a higher fuel-to-air ratio), so that the combustion is incomplete and most soot is formed. A car with a converter is just as polluting as one without a converter in these first few kilometres. Diesel engines tend to produce more particulate matter than petrol engines and cars, of all types, with a high oil consumption especially so. The particles can be wind-borne over considerable distances, especially in dry conditions.

Particulate matter from friction between tyres and road surfaces

This is an inevitable part of road transport. We all know that a tyre wears down its tread at a rate of (very roughly) 1 mm/5,000 km, depending on the car, the tyre composition, the way it is driven and so on. This represents between 150 and 250 g of rubber compounds per tyre. With 800,000 tyres from private vehicles in Cyprus running 15,000 km/year, on average, it means that about 500 tonnes of rubber compounds are lost. Most of this is transformed into dust and such dust cannot be healthy, even if it is inevitable. 

At the same time, the road surfaces are worn, probably to a similar degree. Most of the surfaces are made from compacted hot melt petroleum bitumen aggregate (usually referred to, incorrectly, as asphalt). The bitumen is formed from the still bottoms after the refining of petroleum and consists of an unrefined mixture of many heavy hydrocarbons and carbon. Almost certainly, some of these hydrocarbons are suspected carcinogens. The quantity of bitumen converted to dust is unknown.

Lead compounds

Tetraethyl lead (TEL) has been added to petrol to prevent "knocking" in engines since about 1923. This allows the compression ratio of the engines to be increased, thereby obtaining a better efficiency without premature ignition and thus damage to the engine.

The quantity of TEL added to petrol was small, up to 0.8 cm³ per litre, but the total quantities of petrol sold are enormous, leading to an annual consumption of thousands of tonnes of the substance. Most of the lead passed through to the exhaust in a variety of compounds, some as gases, some as dust. Lead compounds are very toxic to humans and cause a variety of health problems. In particular, the brain and intellectual development of children is severely retarded when they are constantly exposed to lead compounds. It has been found that the lead content in the blood of children has been reduced by more than 75% in children in the USA since the sale of leaded petrol was banned.

 For the anecdote, the man who discovered that TEL reduced "knocking", Thomas Midgeley, a mechanical engineer with no knowledge of chemistry, was also the same person who discovered CFCs, used in refrigerators, causing depletion of the ozone layer; this one man had on his shoulders the responsibility for two major and potentially dangerous environmental hazards!

Unfortunately, leaded petrol was still on sale in Cyprus up to May 2004, even though its bad effects have been known for over 30 years. This did nothing for anyone and I urge everyone, in the strongest terms, never to use anything but lead-free fuel. If their car is old and will not accept it, then the engine should be modified to allow it to be used (or taken off the road!). It was an anomaly that leaded petrol was still on sale here, when it has been banned for many years in most developed nations.

Environmentally-acceptable cars

Conventional cars

With the present situation regarding public transport in Cyprus, it is acknowledged that the private car is a must for most families. However, the present mindset of buying the biggest and most luxurious car, to impress the neighbours, is little short of irresponsible. A small to medium-sized petrol car with catalytic converter is cheaper to buy, to tax, to insure, to run, causes less pollution and is every bit as comfortable for the lengths of trips possible on a small island - and it is still just as easy to be caught in a radar trap! As I said earlier, anything over 2 litres for an ordinary 5-seater family car is wasteful and, if local roads dictate that you must have 4-WD, there is still a choice of good ones at this level. There is prestige to be gained by showing people that you prefer an environmentally responsible vehicle, rather than a de-luxe limousine or a sports car.

Electric cars

There are no electric cars available or suitable. In any case, if there were a large fleet of them in Cyprus, they would have to be charged from the electricity supply, which is not dimensioned for such a load, and which burn fossil fuel oil, in any case. They are not environmentally acceptable. Wide-scale trials in California have shown that electric cars are not acceptable to the public either; owners of them rarely renew their vehicles with another electric vehicle and many stop using them within a matter of months, they are so inconvenient.

Petrol-electric hybrid cars

It is disappointing that the hybrid car is not available in Cyprus. There are several models, from small coupés to medium saloon cars to people carriers, made in mass production with typical consumptions of 3 to 5 l/100 km, less than half that of a comparable conventional car. Most of them come from Japan but production is also starting in the USA. They have been in production for some years and the technology has been mastered. The American motoring magazine, Motor Trend, mostly directed towards cutting-edge enthusiasts' sports car, has named a hybrid car its Car of the Year 2004; this link is well worth reading, if only to show the direction that the car is heading. The car in question in this link has a town consumption of only 3.96 l/100 km! This means that its 45 litre tank of lead-free petrol will take you an astounding 1,100 km before you have to refill - all around Nicosia!  Because the widespread adoption of such cars would help solve various countries' commitments towards reducing carbon dioxide emissions, there are various subsidies or tax relief available for owners. This should happen here, because some models would be the ideal car for the Cyprus context.

Vegetable oil cars

Theoretically, the "chip-oil" car could be used in Cyprus. This is a standard car with a modified diesel engine designed to use vegetable oils as fuel. The used oil is collected from crisp factories, hotels, restaurants and other sources. It is carefully filtered and refined and then thinned down with a small quantity of kerosene. Of course, it emits just as much pollution as any other diesel car; the difference is that 90 per cent of the fuel is from non-fossil fuel sources and the carbon dioxide is therefore renewable to the same extent. It is uncertain whether the collection, treatment and distribution of used vegetable oil in Cyprus would be commercially viable, because the quantities of raw materials is relatively small and would suffice only for a fraction of the cars on the road. It is unlikely that special non-edible oil-producing crops could complement the availability. However, cars with the modified diesel engines can run equally well on conventional diesel oil, so that the vegetable oil could be used when it was available.

Cars of the future

Nobody can predict the car of the future. The hydrogen-powered fuel-cell car is being much hyped as one possibility, although it is unlikely to be in full production in less than 12 or 15 years from now. Although the protagonists claim that this is the way that private cars will go, there are still many unanswered questions. Some of these issues have been evoked in the essay on Hydrogen. It is shown that it would seem very doubtful whether this type of vehicle would work in the Cyprus context unless the people accepts the notion of nuclear power stations. However, there are severe doubts as to whether the hydrogen fuel-cell cars will ever become a mainstream solution, because:

In the shorter term, it would certainly be the hybrid car that would offer the best solution. By 2006/2007, there will probably be tens of models with very advanced technology available on the market at attractive prices.

Reduction of consumption

Of course, the best way of reducing pollution from cars is not to use them! The first and foremost way is to use public transport. Unfortunately, the public transport system in Cyprus is almost non-existent and is totally unco-ordinated. It is an urgent requirement that this be addressed so that anyone in any locality can reliably reach any other locality in, say, half-a-day with no more than two changes. This could be co-ordinated with mail delivery. The example of the postal buses in some European countries shows that this can be done with radiating services from hubs which are interconnected by high-speed coaches (or rail in some other countries). The crux of the system is that there are always postal buses waiting for the arrival of each coach, having delivered passengers from the outlying areas and waiting to take new passengers back there. This would require very radical planning and infrastructure. The important point is that it must be made convenient. It could be done. 

The idea of a new rail system for the backbone should not be discounted, either. It would be possible to interconnect Nicosia, Limassol and Larnaca with 15 - 25 minute travelling times from city-centre to city-centre, with a spur to Paphos from Limassol. This would require vision, but it would cost little more than adding a third lane in each direction to the motorways. Container freight could also be carried from Limassol port to the other cities, relieving the motorways of their polluting juggernauts.

Of course, as I mentioned earlier, walking the kids to school, rather than using the car, as well as light local shopping would be helpful, especially as cars are at their most polluting on short trips. Planning the heavy shopping, such as to the large supermarkets, to go only once every two weeks, requires some forethought. For the daily perishables, use the nearest shop; even if a salad there costs 20 cents when the large shop charges only 15 cents, the difference is equivalent to only a little over a kilometre in a car in one direction, just for the fuel.

A heavy carbon tax on motor fuels is necessary. This would bring the price of diesel to over that of lead-free petrol, but it is the only way to discourage people from buying cars with high consumptions and encourage those with low consumptions. An initial price of CYP 1.00/litre, rising to CYP 1.50 in five years may be sufficiently impressive. If the car tax on small cars were reduced to a nominal CYP 10.00 per year, rising to CYP 25.00 for <2 litre cars, then to CYP 200.00 for <3 litre vehicles and CYP 500.00 for >3 litres, the message should strike home without disadvantaging the poorer users with small cars.

Conclusion

It would be possible to reduce car-engendered pollution in Cyprus, including carbon dioxide emissions, very significantly. This would require a three-pronged approach involving public transport, low-consumption cars (especially hybrids) and public awareness to allow them to use their cars more efficiently. More incentives are required to further these aims and particularly to discourage "gas-guzzlers".

Discuss anything related to this page at this forum.

The opinions on this site are personal and do not necessarily reflect those of any third party. All information is given in good faith but no responsibility is taken for such information; any person or organisation using such information should ascertain that it is suitable for his/her/their conditions of use.

No reproduction of the contents of part or the whole of this site may be made in any form without the written permission of the owner. An exception is made that a print-out may be made for one individual's private use without seeking permission; it is forbidden to make multiple copies or to photocopy a print-out. Links may be made to this site.

Contact us

Copyright © CypEnv 2004/2007