How Everything Works
How Everything Works How Everything Works

Question 386

What is the correct way to dispose of fluorescent lamps? Do they really have mercury inside them? Is the powder that covers the inside of them dangerous? Is there a simple way to get rid of a burned fluorescent lamp without pollution? - Augusto
While there is mercury in a fluorescent lamp, the amount of mercury is relatively small. There are only about 0.5 milligrams of mercury in each kilogram of lamp, or 0.5 parts per million. In fact, because fluorescent lamps use so much less energy than incandescent lamps, they actually reduce the amount of mercury introduced into our environment. That's because fossil fuels contain mercury and burning fossil fuels to obtain energy releases substantial amounts of mercury into the environment. If you replace your incandescent lamps with fluorescent lamps, the power company will burn less fuel and release less mercury. That's one reason to switch to fluorescent lamps, even if you must simply throw those lamps away when they burn out. Nonetheless, there are programs to recycle the mercury in fluorescent lamps. Last year, the University of Virginia recycled 31 miles of fluorescent lamps. They distilled the mercury out of the white phosphor powder on the inner walls of the tubes. Once the mercury has been removed from that powder, the powder is not hazardous. The university also recycled the glass. One last note: the mercury is an essential component of the fluorescent lamp—mercury atoms inside the tube are what create ultraviolet light that is then converted to visible light by the white phosphor powder that covers the inside of the tube.

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