How much mercury is contained in a CFL?
Each bulb contains an average of 5 milligrams
of mercury, “which is just enough to cover a ballpoint pen tip
,” says Leslie, associate director of the Lighting Research Center at Rensselaer. “Though it’s nothing to laugh at, unless you wipe up mercury [without gloves] and then lick your hand, you’re probably going to be okay.”
How do CFLs and incandescents compare in terms of electricity consumption?
On average, CFLs require about 25 percent of the electricity as their incandescent counterparts to produce equivalent light. Replacing an incandescent with a CFL ultimately decreases the amount of electricity the nation’s power plants must generate and, in turn, the amount of carbon dioxide—a powerful greenhouse gas—that they emit into the atmosphere.
How much mercury do power plants emit to light a CFL?
About 50 percent of the electricity produced in the U.S. is generated by coal-fired power plants. When coal burns to produce electricity, mercury naturally contained in the coal releases into the air. In 2006, coal-fired power plants produced 1,971 billion kilowatt hours (kwh) of electricity, emitting 50.7 tons of mercury into the air
—the equivalent amount of mercury contained in more than 9 billion CFLs (the bulbs emit zero mercury when in use or being handled
Approximately 0.0234 mg of mercury—plus carbon dioxide, sulfur dioxide and nitrogen oxide—releases into the air per 1 kwh of electricity that a coal-fired power plant generates. Over the 7500-hour average range of one CFL, then, a plant will emit 13.16 mg of mercury to sustain a 75-watt incandescent bulb but only 3.51 mg of mercury to sustain a 20-watt CFL
(the lightning equivalent of a 75-watt traditional bulb). Even if the mercury contained in a CFL was directly released into the atmosphere,
an incandescent would still contribute 4.65 more milligrams of mercury into the environment over its lifetime.