One approach to increasing efficiency of lighting is the use of compact fluorescent lamps (CFLs). These are compact versions of fluorescent lamps that are designed to fit into fixtures developed for conventional incandescent light bulbs, and use 70-75% less energy than incandescent bulbs. EISA set efficiency standards for incandescent bulbs , which will require development of more efficient incandescent bulbs but which CFLs can now achieve. A potential disadvantage of CFLs is that they contain a small amount (approximately 2-6 mg) of mercury (Hg), which can be released if the bulb is broken or if it is disposed of improperly or incinerated (a concise overview of this issue is provided by the Congressional Research Service ). In situations where a single bulb is broken, such as in a residential setting, the amount of Hg present is estimated to be low enough to avoid any health risk. Recent research has identified the potential for using nanomaterials as a means to absorb Hg in the event a bulb breaks, which would further reduce any immediate risk of individual exposure to Hg in residential or commercial settings .
Even with improvements to minimize individual exposures, improper disposal of significant numbers of CFLs could lead to an avoidable increase in Hg emissions to the environment. Over 270 million CFLs were sold in 2007, accounting for approximately 20% of the U.S. light bulb market. If all the Hg in these bulbs were to be released to the environment, that would account for 0.6-1.8 tons of Hg. If 100% of the U.S. light bulb market were in the form of CFLs that would result in a potential 3-9 tons of Hg that could be released into the environment if all the CFLs were disposed of improperly (an unlikely scenario), eventually on an annual basis as a steady state of failure and replacement was achieved. This compares to over 70 tons per year of Hg emissions to the air from U.S. stationary sources, as estimated from the Toxics Release Inventory .
Light emitting diodes (LEDs) are being developed for and applied to lighting applications, with significant decreases in energy consumption compared to large (100 W) incandescent bulbs and without the issue of Hg associated with CFLs. Although high-brightness LEDs are currently used for only a very small fraction of general illumination, they represent the fastest-growing segment of the LED market . As LEDs are increasingly used for general illumination, they will add to the manufacturing and disposal issues noted above for electronics in general. In particular, LEDs typically contain arsenic, indium, and phosphorous, which may need to be more closely monitored in production and disposal locations. There has not been any indication that these elements are sources of personal exposure during use.
Was this article helpful?