COMPUTER
My computer stares at me 40 hours a week.

COMPOSITION: It's made up of 25 kilograms of plastics, metals, glass and silicon. But its heart is just a hundredth of a kilo of silicon and metal formed into integrated circuits known as 'chips'. Though weighing next to nothing, making these chips generated the most waste. The 400-step process involved silica, carbon, hydrochloric acid, hydrogen, ultra-violet rays, phosphorus, boron, gold, silver, several sensitive chemicals and precision machinery. Factories in Oregon, California and Malaysia were involved. In the Malaysian factory workers got two dollars an hour cutting silicon-chip wafers.

The computer's circuit boards were made of copper, fibreglass, epoxy resin, more chemicals, energy, water, tin solder, and the monitor was of glass, chemicals and lead.

IMPACT: The factories making my 25-kilo computer, generated 63 kilos of waste, used 27,700 litres of water and 2,300 kilowatt hours of energy. By the year 2005, about 150 million personal computers will have been sent to landfills in the US ­ enough to fill a football field a mile high with computer trash.

ACTION: The best thing I can do is upgrade the memory when I need to rather than replace the machine. And switch it off when not in use. But I should have gone for a flat-panel display lap-top in the first place: they produce half as much waste to make and run on a third of the power.

T-SHIRT
I bought my cotton-polyester shirt in my local department store because I liked its colour.

COMPOSITION: The polyester in it started life as a few tablespoons of Venezuelan petroleum. A refinery in the Netherlands Antilles 'cracked' the petroleum at high temperature to produce smaller molecules needed to make the polyester. Further processes, at a chemical plant in Delaware, involved heavy-metal catalysts like cadmium acetate.

The Mississippi field where my shirt's cotton was grown was first fumigated with the toxic pesticide 'aldicarb'. Five times the cotton crop was sprayed with pesticides, mostly organo-phosphates which damage the central nervous system. Finally, it was sprayed with paraquat defoliant to avoid leaf-staining. The cotton and polyester fibres were combined in a North Carolina textile mill. Workers bleached, dyed and finished the fabric with industrial chemicals, including chlorine, chromium and formaldehyde. The shirt was sewn in a Taiwanese-owned factory in Honduras, by women workers earning about 30 cents an hour.

IMPACT: From the oil field to the garment factory, making my shirt's polyester released 25 per cent of its weight in air pollution, including nitrogen and sulphur dioxides, hydrocarbons, particulates, carbon monoxide and heavy metals. These impair breathing, aggravate lung and heart diseases and suppress the immune system. Cotton, meanwhile, accounts for a tenth of the world's total consumption of pesticides ­ many of them harmful to health.

ACTION: The best I can do is avoid synthetics and go for organically grown, natural-fibre products ­ if I can find them!

COLA
Feeling thirsty, I grab a can of cola.

COMPOSITION: My cola consists of 90-per-cent water combined with high-fructose corn syrup, citric acid, flavour concentrate (a secret ingredient including caffeine) and carbon dioxide. Costing much more to make than the cola was its aluminium container. A third of the aluminium in my 15-gramme can was recycled. The other 10 grammes began as 40 grammes of bauxite ore strip-mined in the Australian 'outback'. The bauxite was crushed, washed, dried, pulverized, mixed with caustic soda and roasted with calcium oxide to produce aluminium oxide. This was sent, by a Korean ship, to a smelter in Washington where it was dissolved in baths of cryolite.

Carbon electrodes were lowered into the baths to deliver a massive 100,000-amp jolt of electricity to break oxygen atoms away from the aluminium and to attach them to carbon. Small amounts of perfluorocarbons (PFCs) - greenhouse gases that trap thousands of times more heat per molecule than carbon dioxide - escaped from the smelter.

Once pressed into sheets, the aluminium was sent to another factory where high-powered machinery punched, stretched, trimmed, printed and coated the can. At the bottling plant, machines filled the can with near freezing soda and crimped on the top.

IMPACT: Few processes are as damaging to the global climate as aluminium smelting. It's so energy intensive it has earned aluminium the nickname 'congealed electricity' .

ACTION: I should buy drinks in refillable bottles. Even if the cans are 90-per-cent recycled, refillables consume much less energy. If I can't avoid cans I should at least recycle them. Better still I could remember that water is the best thirst-quencher!

TRAINERS
I'm wearing sneakers - 'cross-trainers' they call them, though I don't 'cross-train' or even know what it is.

COMPOSITION: Made up of dozens of different, mostly synthetic, materials my trainers were assembled in a Korean-owned factory in Indonesia. The leather for the upper came from Texan cows, whose hides were sent for tanning in South Korea where labour is cheaper and environmental standards lower. Tanning today is a 20-step process involving strong chemicals. The rest of my shoe was made from petroleum-based chemicals.
The midsole was a custom-designed EVA (ethylene vinyl acetate) foam: a composite of several chemicals which when combined and baked release tiny air bubbles, giving the shoes their cushy feel. Below the heel was inserted the only US-made component ­ a small amber-coloured polyurethane bag filled with a pressurized gas of secret composition. The outer-soles were made of styrene-butadiene rubber, synthesized from Saudi petroleum and local benzene.

IMPACT: The Indonesian women who made my $75-shoes earned $2 a day and worked in temperatures nearing 100-degrees Fahrenheit. Though solvent fumes cause health problems for some workers, the shoe factory itself generated little pollution and used little energy compared with the refineries, chemicals plants and tanneries that made the shoe's components.
Chemicals from tanneries in South Korea are discharged into the Nattong River along with other industrial pollutants, making tap water in the country undrinkable.

ACTION: I could ask myself how many pairs of shoes I really need. And I could buy more durable, even locally made, shoes and have them repaired when necessary.

CAR
When I drive alone 95-per-cent of the energy goes into running the 1,450 kilo car ­ not me, its 64-kilo cargo.

COMPOSITION: My car contains 800 kilos of steel, 180 kilos of iron, 112 kilos of plastics, 86 kilos of fluids and lubricants, 85 kilos of aluminium and 62 kilos of rubber. Nearly half the steel began as scrap, melted in an electric-arc furnace generating eight pounds of toxic dust. The rest came from a far dirtier place ­ an open pit mine in the pine forests of Minnesota. Altogether 1,590 kilos of iron ore was mined, producing 955 kilos of waste rock which was dumped. The ore was taken to a steel mill where it was blasted in a coke-burning furnace producing carbon monoxide and dioxide. Assembling the car involved 10,000 parts, welded in 4,000 spots. Nearly 150,000 litres of water were consumed ­ more than 100 times its weight. My car's body was then painted in Detroit, where it was dipped into baths of detergent, zinc phosphate and chromic acid, before being submerged in air-polluting primer and baked. Six more coats of paint were applied, including PVC solvent. The unusable sludge from overspray was trucked to a landfill.

IMPACT: My car's mainly made of steel ­ the biggest industrial producer of carbon monoxide and hazardous waste. In assembly, painting was the most polluting process, emitting volatile organic compounds (VOCs) which produce smog. However, most of my car's environmental impact comes when I get behind the wheel. During its nine-year lifespan it will use about eight times as much energy as it took to make and the exhaust from my car will combine with others to constitute the world's single largest source of the poisonous greenhouse gas ­ carbon monoxide.

ACTION: Do I really need a car? If the answer is 'yes' then I should use it as little as possible, share it as much as possible and always go for maintaining it rather than replacing it.

BIKE
When I ride my bike to work I use less energy per distance than any other form of transport ­ including walking!

COMPOSITION: My 14-kilo bike consists mainly of steel, aluminium, rubber and plastics. The steel in my frame is made of iron and small amounts of carbon, chrome and molybdenum to make it harder. Such alloy steels are made in mini-mills that melt down scrap metal. The 7 kilos of steel to make the frame and wheels of my bike began in a Chicago junk yard not far from the mini-mill. Making steel from scrap used one fourth the energy of making steel from iron ore. The scrap was melted down in an electric arc furnace. Impurities formed small amounts of gases, 60 grammes of toxic- laden dust and a floating layer of waste. Removing this generated a few grams of sludge tainted with heavy metals. My bike's four kilos of aluminium ­ gears, breaks and spokes ­ came from smelters in Siberia, my entire bike using less aluminium than just one car wheel. The bike also used about eight pounds of synthetic materials: nylon cable guides came from Delaware, polyurethane handlebar grips from Italy, a vinyl and polyurethane seat and butadiene rubber tyres from Taiwan.

IMPACT: On my bike I cause no air pollution and make no contribution to global warming. I consume no fossil fuels and send no toxic chemicals into the air. I take a fraction of the space that cars take on roads and a twentieth of the parking. And biking is safer per mile than driving.

ACTION: It's obvious!