Article: Lethal gas

Tuesday July 7, 2009

By MICHAEL CHEANG

If you truly want to be a greenie, you should reconsider buying that flat screen TV.

NEXT time you turn on that shiny new flat screen plasma television of yours, think about this – that very TV may have contributed to global warming, and helped make the Earth's atmosphere a little warmer for the rest of us.

This is because the manufacturing of plasma televisions includes the usage of a gas called nitrogen triflouride (NF3), a greenhouse gas so potent that it is 17,000 times more lethal as a global warming agent than an equivalent mass of carbon dioxide (CO2). In layman's terms, NF3 is 17,000 better at warming the Earth's atmosphere than CO2.

Replacement killer: The liquid crystal display of computer monitors are made with the use of a heat-trapping gas, NF3.

NF3 is one of the gases used when manufacturing liquid crystal flat-panel displays, thin-film photovoltaic cells and microcircuits. Which basically means that it's not just TVs that use NF3 – it's used also in making semiconductors, monitors, computer microchips, and ironically enough considering the "green-ness" of the technology, solar thin-film photovoltaics used to convert sunlight into electricity.

Even more ironically, NF3 was first used as an alternative to perfluorocarbons, another potent greenhouse gas. At the time, it was believed that the amount of NF3 used in the process was too miniscule to matter. It was even considered so insignificant that it wasn't even included in the 1997 Kyoto Protocol – an agreement signed by 182 countries to reduce greenhouse gases.

However, a team of scientists at the Scripps Institution of Oceanography at the University of California San Diego discovered last year that NF3 is at least four times more prevalent in the atmosphere than originally expected.

The team's results were published in October in Geophysical Research Letters, a journal of the American Geophysical Union. Led by Scripps geochemistry professor Ray Weiss and Jens Muehle, they made the first atmospheric measurements of NF3 by analysing air samples gathered over the past 30 years, and found that there were about 4,200 tonnes of the gas in the atmosphere in 2006 as opposed to the previous estimate of 1,200 tonnes. In 2008, this amount was 5,400 tonnes, which means the quantity of the gas has been increasing about 11% annually.

In short, what was previously considered to be an insignificant greenhouse gas has been quietly increasing its presence, largely in part to the increasing demand for plasma TVs and other electronics that use NF3 in their manufacturing process.

In a study published last June in Geophysical Research Letters, atmospheric chemists Michael J. Prather and Juno Hsu of University of California Irvine called NF3 the "missing greenhouse gas", and said that the market for NF3 has exploded recently with the increase in demand for flat-panel displays.

The gas is also an extremely long-living gas that can take years, maybe centuries, to eradicate from the atmosphere. So even though only a small amount of the gas is released into the atmosphere, it may still add up into one big problem eventually, especially with the increase in demand for plasma products such as TVs, monitors and even mp3 players.

However, that doesn't mean that one should throw out that brand new TV or stop buying them altogether. While the dangers of the gas have finally been highlighted, there is still research to be done to determine just how much damage it is causing to the atmosphere.

Already, steps have recently been made to rectify the NF3 oversight. Scientists all over the world have recommended that the gas be added to the Kyoto Protocol and just last month, the US Congress passed a climate change and energy bill that includes NF3 in the list of greenhouse gases, alongside sulphur hexafluoride, perfluorocarbons, and hydrofluorocarbons (HFCs).

Also in June, the world's first NF3-free thin-film solar module factory was launched in Germany by a company called Malibu. The factory is said to have completely eradicated the use of NF3 from the manufacturing process.

While such measures should be hailed as steps in the right direction, it remains to be seen if the rest of the world recognises the global warming threat of NF3, and acts accordingly before it's too late.

This article was taken from: The Star Online: Go Green Live Green 7 July 2009