Who won the prize, and why is it important?

The prize was shared equally between three winners: Paul J. Crutzen, F. Sherwood Rowland and Mario J. Molina. Their field of expertise was atmospheric chemistry, specifically their discoveries about the ozone layer.

Crutzen, 61, was born in Amsterdam. His school years were disrupted by the Wehrmacht invasion of the Netherlands, but he was able to advance through his education and went to Stockholm University to work as a computer programmer. He studied meteorology, learning about the carbon cycle, cloud physics and acid rain.

In the 1970s he moved to researching stratospheric ozone, a field which had not been explored much before.

Molina spent his childhood in Mexico City, then had his higher education in Europe. In 1968 he began graduate studies into physical chemistry at the University of California. He completed a PhD in 1972 and began to work under Rowland studying CFCs. Chlorofluorocarbons are inert chemicals which at the time were released in a lot of industrial gases. Molina and Rowland developed the “CFC-ozone depletion theory”.

Rowland, 68, was born to an academic family in Delaware. He skipped some academic years and had his final year of university before this eighteenth birthday. In 1973 he started work on atmospheric chemistry, following discoveries by Jim Lovelock. He worked with Molina on the ozone layer, which by 1974 had become a major issue of public concern.

The ozone layer is a section of the Earth’s atmosphere which contains the largest quantities of Ozone gas (O3). It is between 15km and 50km from the surface. Were this layer absent, plant and animal life could not evolve on Earth. Ozone absorbs the ultraviolet radiation from the sun, so that most of it does not reach ground level.

Research by the prize winners revealed that the layer was being damaged by emissions of man-made chlorofluorocarbons into the atmosphere. CFCs were at the time used widely in industry, having been chosen because their inertness and non-toxicity were thought to have made them environmentally harmless. In fact, as it was later realised, CFCs were rising to a similar height as the ozone layer then being blasted by ultraviolet radiation – which split up the molecules, releasing chlorine gas atoms.

In 1970 Crutzen had shown that nitrogen oxide and nitrogen dioxide (formed by the decay of N2O) can also cause a catalytic reaction with O3. This effect accelerates the ozone layer’s deterioration. Combined with that of Harold Johnston, Crutzen’s work sparked fears that the rise of supersonic air travel would destroy the ozone layer, because the aeroplanes would fly at altitudes of around 20km (ie. Within the layer) and release nitrogen oxides among their waste gases.

In 1974, Rowland and Molina showed that CFCs in spray cans also damaged the atmosphere. There were restrictions placed upon their use until 1985, when a hole in the ozone layer was discovered over the south pole. In 1987 the United Nations introduced protocols to protect the ozone layer and by 1996 the offending gases were entirely outlawed. The 1995 prize rewards the contributions of Molina, Crutzen and “Sherry” to our understanding of the ozone layer, without which there might by now have been permanent damage done.

A summary of research into a select halogen.

Fluorine is the lightest of the halogens. It is the most reactive element on the periodic table, and the most electronegative (3.98). It melts at 53.53 and boils at 85.01K, so is normally encountered as a pale yellow-green gas. A fluorine atom has nine protons, ten neutrons and the electron arrangement (1s2 2s2 2p5). Normal fluorine molecules are diatomic (F2), but the element is so dangerously reactive that it is more commonly found as fluoride (F-) ions.

Fluoride is considered an essential chemical in the human body (though the quantities are very small). Overall, the average body contains 3 to 6 grams of fluoride, and takes in 0.3 to 3 miligrams per day. F- makes up 200 to 1200 parts per million, and 0.5 mgL-1 of blood. Fluoride is highly beneficial to teeth, because it converts calcium phosphate into the harder fluoroapatite. For this reason F- is contained by many toothpastes and some countries add it to public water supplies. In medicine, fluoroquinolanes are used to tackle infections which other antibiotics cannot, such as gonorrhea. They work by stopping the coiling of bacterial DNA so to prevent pathogens from multiplying.

For a long time fluoride salts were used in frosted glass and welding, however it was not mass produced until the Second World War when it was used in nuclear energy projects (fluorine gas is used to make uranium hexafluoride which can separate uranium-235 from its less useful isotopes). Various fluorine-based minerals are in industrial use today. Fluorite (or fluorspar) is widely used in the smelting and refining of metals. Around six million tonnes are produced globally each year (mostly in China). F2 gas is widely used for the plasma etching process, used for flat-screen televisions and semiconductors.

In 1802, fluoride was discovered in bones, teeth and ivory. By the mid-nineteenth century, it was found in hair, saliva, urine, blood and brine, but it was not until 1886 that fluorine could be isolated. The achievement was that of French scientist Henri Moissan, who electrolysed potassium bifluoride in Paris.

Fluorine is the 13th most common element in the Earth’s crust, making up roughly 950 parts per million. Large quantities are released into the atmosphere by volcanic eruptions. Various fluoride compounds are also entitled industrially, raising concerns about the environmental impact. The use of chlorofluorocarbons in aerosols, for instance, was banned to stop damage being done to the ozone layer.

While fluoride is a valuable tool in medicine, excess can itself cause health problems. If F- hardens the bones too much, it can result in skeletal deformation. Pure fluorine gas, even in 1/1000 concentrations, is fatal to inhale for a few minutes. In countries where water has high fluoride levels, fluorosis is a major problem which can affect millions.

Sources: chemicalelement.com; terpconnect.umd.edu; rsc.org; brittannica.com; “Nature’s Building Blocks” by John Emsley.

Researching the Quark Model, including Gell-Mann and Zweig

For an organism’s diet to be “balanced”, it must include the correct proportions of all the nutrients that are needed for that organism to function and grow. For humans this means lipids and carbohydrates for energy, mineral salts for growth, vitamins to prevent disease and protein to repair damaged tissues, with water to help transport them all around the body.

Quarks are elementary particles of which all hadrons are composed. They are not directly observable alone, so everything known about them is taken from experimentation with hadrons.

Quarks are unique in that they are the only particles which have fractional rather than integral charges, and the only elementary particles to experience all four of the fundamental forces (the strong nuclear force, the weak nuclear force, electromagnetism and gravity).

Quarks come in six types (or “flavours”): the up quark, the down quark, the charm quark, the strange quark, the top quark and the bottom quark. All quarks have the same “spin” of ½ but they have different charges and masses.

Up: +2/3, 2.5 MeV

Down: -1/3, 4.95 MeV

Charm: +2/3, 1270 MeV

Strange: -1/3, 101 MeV

Bottom: -1/3, 4.2 GeV

Top: +2/3, 172 GeV

Baryons (which include nucleons) are each made up of the three quarks. A proton, for instance, is made of two up quarks and one down quark, giving it a charge of +1. Each meson is made of one quark and one antiquark (each quark has a corresponding antiquark, with the same mass but opposite charge).

Up and down quarks are the most common in the universe, because their lower mass gives them stability. The much heavier top, bottom, charm and strange quarks are less stable and hence particle decay leads them to change rapidly into the up and down flavours.

In 1964, scientists Murray Gell-Mann and George Zweig independently proposed the Quark Model as a way of explaining the properties of particles such as protons and neutrons, though it did not become established as fact until 1977. The physical evidence for their existence came from deep inelastic scattering experiments. In 1968 the discovery of the top quark was not until 1965.

Sources: wikipedia.org; hyperphysics.phy-astr.gsu.edu; universetoday.com

A review of the environmental problems caused by gases produced by industry.

Through most of modern history, the subject of a changing environment is usually discussed alongside the issue of man-made pollutants. The most significant part of this is the “greenhouse gases” – substances produced by human industry or agriculture which have been allowed to escape into the air. They are named thus because of the effect they have – trapping heat from the Sun within the Earth’s atmosphere so that the planet stays warm. Increasing the amounts of these gases will therefore increase the temperature.

Prominent among the greenhouse gases is Carbon dioxide. CO2 is produced whenever hydrocarbons are burned, and therefore large amounts are generated by industries which rely on fossil fuels. It is believed that the concentration of CO2 in the atmosphere has risen by around 30% since the industrial revolution, and it accounts for 75% of global warming by greenhouse gas. Methane (CH4) is another 14% of this, coming mostly from agricultural industries and the rotting of organic materials. A further 8% is caused by Nitrous oxide, which comes from animal waste and nitrogen-based fertiliser.

There have been many different recorded effects of this, such as the global increase in average temperature. In 1900, the temperature was 3.8 degrees. In 2000 it had risen to 4.4 degrees Celsius – and increase of 0.6. Yet it is predicted that by 2100 the temperature will be 5.8 degrees Celsius, meaning that the rate of temperature rise will have more than doubled.

This in itself will lead to other damaging effects – such as a dramatic rise in sea levels as ice melts, leading in turn to flooding of coastal settlements and the contamination of drinking water with salt. It would also have a drastic impact on species or communities whose existence is tied to the land – temperature plays a significant role in determining the sustainability of a particular area, and therefore a sudden rise might destroy a habitat, potentially rendering many currently endangered species extinct and bankrupting groups who subsist from agriculture when their land becomes unusable and their crops worthless.

Another big impact of the temperature rise would be a change in weather – changing water distribution could mean heavier rainfall in some parts of the world and worse droughts in others. This again would force animals to migrate or die. As the creatures move around, so do any pathogens which they carry, which means that diseases are able to spread further than before. It also means more freak weather – such as hurricanes. It is reckoned that, since 1980, the destructive power of the average hurricane has increased by around 50%. thunderstorms, too, have nearly doubled in frequency in some parts of the world and volcanic activity is expected to worsen in the near future.

Outside of “warming” problems, there is a fear that the constant pouring of exhaust gases into the atmosphere could form a “cloud of smog” over the ground, as has already been observed in some major cities. This could have dire consequences for those living there, as it has been shown to lead to a higher risk of cancer, breathing problems and other maladies.

Sources: globalwarmingweb.com; wikipedia.org; environmentalleader.com; theguardian.com; environment.about.com; environment.nationalgeographic.co.uk; environmentalgraffiti.com