Monday, September 20, 2010

Compact Fluorescent Lightbulbs-the dangers (possibly)

Fluorescent bulbs have an interesting history starting with French astonomer Jean Picard noting a faint glow coming from his mercury barometer whenever he moved it.  Francis Hauksbee, forty years later, showed that when liquid mercury rubs against glass it produced a static electrical charge which in turn caused mecury vapour to glow.  Daniel MacFaralan Moore, who worked for Thomas Edison, started up a competing company manufacturing fluorescent tubes containing carbon dioxide (it riddled with problems but is the first example of fluorescent lights).  P. Cooper Hewitt demonstrated that mercury vapour was superior to other gases for producing light.  Unfortunately it produced a blue-green light.  Jacques Risler, in 1926, applied a coating to the inside the tubes that absorbed the ultraviolet light and re-emitted it as a nice visible light.  Compact Fluorescent bulbs were introduced in 1973 due to the energy crisis cause by the Middle East War at the time.

  Compact Fluorescent Lightbulbs (CFLs) are green.  They use 75 percent less power than incandescent bulbs.  This adds up to a savings of about $30/bulb and also less carbon dioxide emissions.  If every home in North America used one CFL it would be the equal to taking a million cars off the road. 

It is true that CFLs do contain mercury and is a possible source of pollution.  However, consider that coal-fired power plants put out mecury in the air.  If less energy is required, less coal is burned and therefore less mercury is released.   CFLs usually contain less than 5 milligrams (the size of a period on this page) of mercury (in comparison with the older type thermometers containing 500 milligrams).  So the amount in CFLs is hardly significant.

There have been many viral emails suggesting that when they break, CFLs require a special clean up crew.  This is false, and can end up costing one a lot of money (reports of $2000 have surfaced).  It is true that care needs to be exercised when cleaning a broken CFL.  The bulbs are disposed of at toxic waste depots as opposed as with ordinary household trash.  The mercury in the bulbs is actually recycled.  Clean up according to some sources:
  1. Ventilate the area
  2. Wear Gloves, dust mask and older clothing that covers the skin.
  3. Collect the larger pieces into a sealed container
  4. Collect the dust using a dust pan and small broom or two sheets of stiff paper (spill kits are also commercially available).  Use a vaccum for carpets.  Put inside sealed container
  5. Pat the area with the sticky side of duct or masking tape and then clean area with a damp cloth.
  6. Put all material used to clean up (clothes, rags, paper, tape) into a plastic bag.
  7. Label waste as Universal Waste-Broken Lamp and check with your locality for disposal requirements.
Other health concerns have arised as well due to CFLs.  They do flicker and that can cause migraines and eye strain.  Some people have claimed elecromagnetic sensitivity to them.  Thus far though, double blind tests have shown people who do claim electrosensitivity to not be able to identify when they are being subjective to an EMF.

Britian's Health Protection Agency investigated UV radiation from single and double envelope bulbs.  Single are the ones where the coils are visible where the double look almost like regular incandescent bulbs.   It was found that the double emitted almost no UV light while the single bulbs did emit enough to cause skin reddening, but only when exposure was continuous at a distance of less than 25 centimetres.  This poses little threat to the general population.  However, with certain diseases like Lupus, which increases the sensitivy to UV light, the single CFLs can be a problem.  It can cause rashes and serious skin lesions.

So CFLs are relatively safe and do no pose a great risk.  Some of the concerns do have their merits, as noted above, but are not at the level at which some viral emails suggest.  Just follow the clean-up (search for more detailed instructions) if required and choose the bulb best suited for your lifestyle and activities.

Science, Sense and Nonsense--Joe Schwarcz
Voodoo Science--Rober Park

No comments:

Post a Comment