The very title I chose for this story sounds ominous, which was intentional. On a side note this post got way way bigger than expected, it is partially written by myself but much of it is pulled directly from whale.to/b/simons. which I have significantly truncated as I like I suspect many of you whilst having an interest do NOT want to read an entire encyclopedia on the subject 🙂
Unleaded petrol is the modern Trojan horse, it was created because Governments around the world acted to ban the addition of lead to petrol as an anti-knock agent and instead oil companies began to sell unleaded petrol.
The very terms “leaded” and “unleaded” are misleading. They give the impression that “leaded” petrol is contaminated with something nasty, namely lead, while “unleaded” is somehow pristine, pure. Whilst it is true that “leaded” petrol contains lead, and lead is not a nice substance to have spewing out of the exhaust pipes of millions of cars, the truth is that unleaded petrol has even nastier properties.
There are three main groups of substances the oil companies use instead of lead.
1. Aromatics-organic compounds based on the benzene ring, a 6-carbon ring with 3 delocalised double bonds, e.g., benzene, toluene, xylene, etc.
2. Olefines-organic compounds which have double bonds. After combustion, one critical by-product is 1,3-butadiene.
3. Oxygenates-organic compounds containing oxygen molecules such as methane, ethane or MTBE (methyl-tertiary-butyl ether).
Health effects of Aromatics, especially Benzene
Dr Arthur Chesterfield-Evans, an occupational health expert, believes the public had been misled by claims that by removing the lead from petrol, its negative environmental and health effects have been reduced. He says, “We have been subject to a concentrated disinformation campaign in the form of a seductively simple ‘no lead, no worries’ message.”
The US EPA claims that half of all cancer cases may be related to air pollution. For a lifelong exposure to a microgram of benzene per cubic metre (approx. 1 part per billion), it estimates that 2.8 people per million will be diagnosed with leukaemia. The World Health Organisation comes up with a figure of four leukaemia cases per million, and the German Cancer Research Centre with nine projected cases.
In 1977, Prof. Maltoni’s Foundation showed that benzene was a powerful carcinogen causing many types of cancers, particularly leukaemia. Many other aromatics were tested and they all proved to be carcinogenic. Several other compounds contained in vehicle emissions were also found to be carcinogenic.
Professor Maltoni said, “There are risks with gasoline containing high aromatic hydrocarbons, risks with US gasoline containing high paraffin content, and risks with oxygenate-additive gasolines. Particular concern must be attached to gasolines with a high aromatic hydrocarbon content. Benzene is one of the most powerful industrial carcinogens. Alkyl benzenes likewise entail cancer risk.”
Many alkyl benzenes break down to benzene in the combustion process. Dr Michael Dawson says that approximately 50% of the benzene emitted from the exhaust comes from the actual benzene in the fuel, 40% is from the toluene (methyl benzene), and 10% from other aromatics in the fuel.
Dr Simon Wolff, of University College London School of Medicine, was originally concerned about Britain’s nuclear power- plants. He noticed a tenfold difference in childhood leukaemia rates between certain populations, so he began searching for explanations. He concluded that newer middle-class suburbs and towns with high levels of car ownership and use were the most at risk.
Dr Wolff says that Britain’s plan to cut benzene levels to one p.p.b. is still not enough. “We should be aiming to lower the lifetime risk of leukaemia to one in a million, compared with 10,000 at present. To achieve that we have to cut benzene levels by fifty- or one-hundredfold. Children could develop cancer at much lower benzene exposure levels than adults, because they breathe faster, have much faster metabolism, and their bone marrow is more sensitive.
Studies from Sweden have found unexpectedly high levels of leukaemia in petrol-station workers.
Dr Michael Dawson asks, “Why are oil companies allowed to substitute a carcinogen (or compounds which are converted to a carcinogen) for a neurotoxin?” The carcinogen is released into the air we breathe, while the neurotoxin it replaces comes out of the exhaust as lead oxide or lead chloride which is baked hard and falls to the ground near the road.
Professor Roger Perry says, “I find it really difficult to understand how any government or any serious scientist could take the issues of low levels of lead seriously, and decide to ignore issues such as benzene where levels are already high enough for concern.”
Professor Bill McCarthy, head of the Sydney Melanoma Unit, Royal Prince Alfred Hospital, Sydney, says: “Benzene is a highly carcinogenic agent. It causes lung tumours, liver tumours, renal tumours, kidney tumours, leukaemia and skin tumours
In Switzerland, it is now compulsory for every petrol pump to be fitted with a negative-pressure vapour hood. This is a device that pumps all the air that is displaced by the petrol, into a holding tank. Therefore, the fumes do not escape into the atmosphere, and a little petrol actually re-condenses in the holding tank. They also use this method in some parts of the US, but there are no plans to use these in Britain or Australia.
On the plus side (sort of) or at least theory, a catalytic converter is supposed to convert 90% of the unburnt part of the fuel and turn it into a safer substance, however its a very short term ‘plus’ as catalytic converters generally take 5-15 minutes to warm up and they cease to work after 40,000 to 50,000 kilometers. So, much of the time, they’d definitely not be doing what they’re supposed to be doing.
It gets worse
Catalytic converters are made up of either palladium or platinum which aside from being rare which in turn of course makes it very expensive. In 2007, Russia was the top producer of palladium, with a 44% world share, followed by South Africa with 40%. Canada with 6% and the U.S. with 5% are the only other substantial producers of palladium.
The smelting of platinum can release metals into the air, particularly osmium tetroxide, as the companies that smelt it don’t use scrubbers to remove it, current levels are so low they are of no concern to the environment at this time however the more we mine the greater the levels.
Platinum can take up to six months to be refined. On average, seven to 12 tonnes ore yields one ounce of high grade platinum. The beneficiation process begins with the underground extraction of platinum-rich ore, which is then ground into workable chunk sizes. The froth flotation method is used to extract the metal by mixing these particles with reagents, and having air pumped through the material. Platinum-containing particles float to the top.
Of the 245 tonnes of platinum sold in 2010, 113 tonnes were used for vehicle emissions control devices (46%), 76 tonnes for jewellery (31%). The remaining 35.5 tonnes went to various other minor applications, such as investment, electrodes, anticancer drugs, oxygen sensors, spark plugs and turbine engines.
So that 35274 ounces in total and in turn between 246918 and 43288 tonnes of ore that has to be mined per year. And while modern mining machinery may use catalytic converters I personally wouldn’t expect them to replace them as and when needed.
So in in all likelihood in order to produce a device to prevent pollution from exhausts we produce more in the mining of the metals, the smelting and during the manufacturing process to end up with a product that will only last up to 50,000 km (31068 miles), only work properly for less than half that time before it needs replacing.
I must admit I am at a bit of a loss for words here, when I embarked on this story I was not expecting the results I found, finding sites on how wonderful unleaded petrol is and how amazing catalytic converters are is easy, finding information about the harmful aspects is somewhat more difficult and even harder to understand when you do find them, hopefully I have skimmed out most of the unintelligible jargon i.e. the parts where you need to be a biochemist or a metallurgist to understand it.
The only hope we have in the future for clean sustainable fuels I suspect will be hydrogen cells, while solar power is sustainable I suspect the panels themselves are not quite so clean to manufacture i.e. more precious rare metals (will leave that for another story if I can face it lol)
Disclaimer: Most of the excerpts in this post are from http://www.whale.to/b/simons compiled by Catherine Simons, B.Sc. from articles by Peter Sawyer, Graham Allum and Simon Grose in Nexus magazine. Whilst some of the figures will have changed / increased over the years, ultimately poison is still poison and that hasn’t changed.