Brilliant_ The Evolution of Artificial Light - Jane Brox [109]
While developers of compact fluorescents continue to search for a more accommodating white light (read: closer to that of incandescence), the use of compact fluorescents has slowly accelerated in this country. In 2008 they constituted about 19 percent of all bulbs sold in the United States. Eventually, consumers may have little choice but to purchase them once new efficiency standards for illuminants imposed by Congress begin to take effect in 2012. These new standards will make the sale of most incandescent bulbs illegal. In response, researchers are currently developing more efficient incandescent lights, such as the Philips Halogená, but they are ten times more expensive than standard filament bulbs.
The efficiency of CFLs means that their use lowers mercury emissions at coal-fired generating plants, but CFLs themselves—like all fluorescents—contain mercury, a highly toxic metallic element that accumulates in the environment and can affect the nervous systems of living creatures. And at the moment, the disposal of compact fluorescents isn't regulated. Almost all compact fluorescents—and the mercury in them—end up in the trash, creating a considerable environmental problem of their own. In 2009 the state of Maine adopted the first extensive regulations concerning compact fluorescents, and once the law goes into effect, it will limit the amount of mercury manufacturers are allowed to use in the bulbs. The law also requires that a mandatory recycling program, paid for by bulb manufacturers, be established by 2011.
In the meantime, the Maine Department of Environmental Protection is so concerned about mercury from bulbs leaking into the environment that it not only urges householders to carefully recycle compact fluorescents but has also posted a fourteen-point instruction sheet on how to clean up one broken bulb. It begins: "Do not use a vacuum cleaner to clean up the breakage. This will spread the mercury vapor and dust throughout the area and could potentially contaminate the vacuum. Keep people and pets away from the breakage area until the cleanup is complete. Ventilate the area by opening windows, and leave the area for 15 minutes before returning to begin the cleanup. Mercury vapor levels will be lower by then."
The environmental problems posed by the mercury in CFLs is disadvantageous enough to brand them as transitional lighting, eventually to be replaced, perhaps, by light-emitting diodes (LEDs), which are composed of miniature plastic bulbs illuminated by the movement of electrons in semiconductor material. There is no filament to burn out and no mercury to recycle. They are the coldest of lights. LEDs are already used widely for digital time displays, scoreboards, traffic signals, and Christmas and other decorative lights. In the past few years, as the technology has advanced, they've begun to be used for street lighting and, more rarely, for interior lighting, but the "white" light still has a bluish cast, and unlike traditional bulbs, LEDs shed light in one direction only. Although it's possible for LEDs to last decades, they are still quite expensive to purchase—generally more than ten times the cost of an incandescent bulb.
Major lighting companies such as General Electric and Philips are already looking beyond LEDs to organic light-emitting diodes (OLEDs), which work by passing electricity through thin layers of organic semiconductor material that is sandwiched between charged substrates. OLED lighting is still in its research-and-development stage, but its champions have faith that it will last ten times longer and "burn" ten times more efficiently than incandescent lights. OLEDs, a true departure