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Not quite convinced? Here are answers to some common questions about compact fluorescent bulbs (CFLs) and mercury.
Why is there mercury in CFLs?
Compact fluorescent bulbs are made of glass tubes filled with gas and a small amount of mercury. CFLs produce light when the mercury molecules are energized by a current of electricity running between two electrodes in the base of the bulb. The mercury emits ultraviolet light, which in turn energizes the tube’s phosphor coating, leading it to emit visible light. No mercury is released by CFLS during their use and or handling. The mercury only becomes an issue if the bulb breaks or is disposed of improperly.
Why isn’t there mercury in regular incandescent bulbs?
Incandescent bulbs produce light in a different way. Incandescent bulbs produce light by heating the metal filament inside the bulb. When electricity passes through the filament, its temperature rises to 2,300 degrees Celsius. This causes the filament to glow white-hot and emit light. Only 5 to 10 percent of that electricity is transformed into visible light. This inefficiency is the reason why incandescent bulb wattages are so much higher than the wattages of equivalent CFLs. This is also the reason why incandescent bulbs get so hot while in use.
How much mercury is contained in a CFL?
Each bulb contains an average of 5 milligrams of mercury, approximately enough to just cover the tip of a ballpoint pen. Some brands use less. The lighting industry continues to evolve and promising new technologies are in development.
How do CFLs and incandescent bulbs compare in terms of electricity consumption?
On average, CFLs require about 75 percent less electricity than an incandescent bulb of similar light output. For example, a 60 watt incandescent bulb can be replaced by a 15 watt CFL. So for every hour of operation, the CFL uses 45 fewer watts of electricity. Assuming an average Kilowatt/hour cost of $.10, each CFL will save a homeowner an average of $45 over the life of the CFL.
Even if the cost of electricity is not a pressing issue for your household, remember that replacing an incandescent with a CFL decreases the amount of electricity the nation’s power plants must generate and, in turn, the amount of greenhouse gasses and mercury that they dump into the environment.
How much mercury is emitted by power plants?
Approximately 50% of all the electricity in the US is generated by coal-fired power plants. When coal burns to produce electrictiy, the mercury that is a naturally occurring component of coal is released into the air. In 2006, coal-fired power plants produced 1,971 billion kilowatt hours of electricity and 50.7 tons of mercury
Do Incandescent Bulbs have a greater impact on mercury in our atmosphere than CFLs?
- For every Kilowat hour of electricity generated by coal-fired power plants, .0234 micrograms of mercury is released into the air.
- Over the 7,500 hour average life of one CFL, then, a plant will emit 13.16 micrograms of mercury to power a 75 watt incandescent bulb versus 3.51 micrograms for a 20 watt CFL (which is the the light equivalent of a 75 watt incandescent 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.
How much of a difference can CFLs really make?
According to EnergyStar—a program run by the Environmental Protection Agency—if each U.S. home replaced one incandescent bulb with a CFL, the electricity saved each year could light 3 million homes and prevent greenhouse gas emissions equal to that of 800,000 cars.
What is the proper way to handle a broken CFL?
According to the Environmental Protection Agency, these are the procedures to follow if a bulb is smashed:
- Open the windows and let the room air out for 15 to 30 minutes,
- Using disposable gloves, scoop the glass onto a piece of cardboard.
- Wipe the area with a wet paper towel.
- For smaller pieces of glass and powder, use duct tape to pull up the fragments.
- Put all of the debris as well as the duct tape and gloves into a plastic bag, put into a bulb recycling kit or contact your town office for information on disposal of hazardous materials.
- Wash your hands.
What is the best way to handle a CFL?
Most bulbs are broken during installation and removal. To cut down on the risk of creating a mess, slide a small sandwich bag over the bulb prior to handling it. That way, if the bulb slips from your hand and falls to the ground, the mess will already be contained.