I recently came across a figure from the Natural Resources Defense Council that compared the “Overall Mercury Impacts of 100W Equivalent Light Bulbs over the Lifetime of a CFL.” I like the figure because it estimates the total mercury emissions for various types of light bulbs and breaks it down into how much is emitted from a coal-burning power plant and how much is contained in the bulb itself. It visually depicts that incandescents and newer, light emitting diode (LED) bulbs, do not contain mercury. Given that coal-burning power plants are responsible for much of the airborne mercury in the U.S. I want students to be aware that using any light bulb will result in mercury emissions as long the electricity comes from a coal burning power plant. I also want them to know that through the use of more efficient bulbs and through conservation behaviors (e.g. turning off a light when not in use) we can reduce the amount of mercury emissions generated by our lighting choices. I also like that the figure includes analysis of LED bulbs which are emerging as substitutes for incandescents and Compact Fluorescent (CFL) bulbs and do not have mercury contained inside.
The NRDC has created a two page fact sheet titled The Facts about Light Bulbs and Mercury that addresses this topic in the context of the 2007 Energy Independence and Security Act (EISA) which established energy-efficiency standards for new light bulbs.