Who Regulates Mercury in CFLs?ĭespite its relatively low concentration in CFLs, mercury is still a toxic substance. On the other hand, a tuna fish sandwich, which contains the more hazardous methylmercury, is estimated to expose the consumer to more than 48 times that amount due to the more efficient method of consumption (literally eating the mercury). A paper in the August 2009 issue of the lighting journal LD+A found that the median amount of mercury vapor to which a person is exposed through a broken CFL is a tiny fraction of the total mercury contained within the bulb: Approximately 0.07 micrograms (0.0007 mg). In the case of a broken CFL, the most likely form of exposure comes from inhaled mercury vapor. Keep in mind, however, that the mercury contained in a CFL, thermometer, or dental filling can be present in these sources in two forms: A liquid, which is what we typically think of when we think of mercury, and a vapor that quickly dissipates. This pales in comparison to older thermometers, which contain as much as 500 mg and even amalgam dental fillings, which contain about 100 mg of mercury. As of November 2010, the US EPA’s Energy Star program concluded that the average amount of mercury within a screw-in CFL was 4 milligrams, comparable to the size of a ballpoint pen tip. The amount of mercury contained within a CFL varies, and in general, has decreased since their introduction nearly two decades ago. In short, without mercury, fluorescent lights will not work. The technology is the same for both linear fluorescent tubes (like those seen in office buildings) and self-ballasted compact fluorescents (the "spiral" bulbs used in homes). In turn, the mercury vapor emits ultraviolet light that excites the phosphor coating within the fluorescent tube, producing visible light. The cathodes within a fluorescent tube produce electric current that passes through argon gas and mercury vapor. Mercury (Hg) is a naturally occurring element used in applications as varied as thermometers, dental fillings, and fluorescent lighting. But what are the facts? Why Use Mercury in CFLs? On the other side, groups feel such rhetoric is overblown. Those against the use of CFLs claim that the potential harm of toxic mercury contained within the energy-saving bulbs far outweighs any environmental benefits. Lighting topics don’t get much more exciting than the debate over the mercury content of compact fluorescents (CFLs).
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