Friday, February 22, 2013

Are CFL Bulbs Safe?



Are CFL Bulbs Safe?
I read an article that said that "CFL bulbs emit high levels of ultraviolet radiation--UVC and UVA rays. Also, that "the UV rays are so strong that they can actually burn skin and skin cells". Further, the writer stated that "experts say the radiation could initiate cell death and cause skin cancer in its deadliest form."

Is this really true? It sounded too alarmist for me, so I decided to find out the truth. What I did find is that yes, there is some radiation but it is too small to contribute to skin cancer and the double enveloped glass casing of the bulbs helps to mitigate the radiation risk.

Second, there is mercury in CFL bulbs so careful disposal is important. Most people are not aware of the presence of mercury so they dump used CFL bulbs in the trash. There needs to be awareness of the proper way to dispose of used CFL bulbs.


Finally, I learned that CFL bulbs emit less heat than incandescent bulbs so in colder climates, we actually end up needing more heat from radiators to make up for the heat that we give up when we use CFL bulbs. That probably helps to partly explain why my electricity bill is still high in the winter even after replacing all my bulbs with CFLs. 
The conclusion is that CFL bulbs are relatively safe but need to be disposed off properly to reduce the risk of mercury being dumped in an unsafe manner.
Here is an extract regarding the health risk of CFLs from the Wikipedia page on Compact Flourescent Lamps:

Human health


"According to the European Commission Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) in 2008, CFLs may pose an added health risk due to the ultraviolet and blue light emitted. This radiation could aggravate symptoms in people who already suffer skin conditions that make them exceptionally sensitive to light. The light produced by some single-envelope CFLs at distances of less than 20 cm could lead to ultraviolet exposures approaching the current workplace limit set to protect workers from skin and retinal damage. Industry sources claim the UV radiation received from CFLs is too small to contribute to skin cancer and the use of double-envelope CFLs "largely or entirely" mitigates any other risks.[51]
A 2012 study comparing cellular health effects of CFL light and incandescent light found statistically significant cell damage in cultures exposed to CFL light. Spectroscopic analysis confirmed the presence of significant UVA and UVC radiation, which the study's authors conjectured was attributable to damage in the bulbs' internal phosphor coatings. No cellular damage was observed following exposure to incandescent light of equivalent intensity. The study's authors suggest that the ultraviolet exposure could be limited by the use of "double-walled" bulbs manufactured with an additional glass covering surrounding the phosphor-coated layer.[52]

Environmental impact

Mercury content


Net mercury emissions for CFL and incandescent lamps, based on EPA FAQ sheet, assuming average U.S. emission of 0.012 mg of mercury per kilowatt-hour and 14% of CFL mercury contents escapes to environment after land fill disposal
CFLs, like all fluorescent lamps, contain mercury[53][54] as vapor inside the glass tubing. Most CFLs contain 3–5 mg per bulb, with the bulbs labeled "eco-friendly" containing as little as 1 mg.[55][56] Because mercury is poisonous, even these small amounts are a concern for landfills and waste incinerators where the mercury from lamps may be released and contribute to air and water pollution. In the U.S., lighting manufacturer members of the National Electrical Manufacturers Association (NEMA) have voluntarily capped the amount of mercury used in CFLs.[57] In the EU the same cap is required by the RoHS law.
In areas with coal-fired power stations, the use of CFLs saves on mercury emissions when compared to the use of incandescent bulbs. This is due to the reduced electrical power demand, reducing in turn the amount of mercury released by coal as it is burned.[58][59] In July 2008 the U.S. EPA published a data sheet stating that the net system emission of mercury for CFL lighting was lower than for incandescent lighting of comparable lumen output. This was based on the average rate of mercury emission for U.S. electricity production and average estimated escape of mercury from a CFL put into a landfill.[60] Coal-fired plants also emit other heavy metals, sulphur, and carbon dioxide.
In the United States, the U.S. Environmental Protection Agency estimated that if all 270 million CFLs sold in 2007 were sent to landfill sites, around 0.13 metric tons of mercury would be released, 0.1% of all U.S. emissions of mercury (around 104 metric tons that year).[61]
The EPA updated their mercury comparison graph in November 2010. The graph assumes that CFLs last an average of 8,000 hours regardless of manufacturer and premature breakage. In areas where coal is not used to produce energy, the content emissions would be less than the power plant emissions for both types of bulb.[62]"

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