Fluorescent lamps, although saving electrical energy, must be handled with precautions as they contain varying amounts of Mercury and smaller amounts of other metals, as Nickel, Sink, Cadmium, Lead and Manganese. Furthermore some bad quality lamps and also older lamps, may leak Ultraviolet light, with a wavelength of 253 nm in the lower part of the spectrum and invisible to human eyes. Specially watch out for the larger size fluorescent tubes which soon might loose the phosphor coating at the extremes of the tube.
The visible part of the light in the spectrum is roughly between 400 to 700 nm.
It is advisable to avoid working closer than 30 cm from and looking into the light of fluorescent lamps, the Ultraviolet light is invisible to us, but nonetheless can cause skin and eye damage.
Fluorescent lamps come in different models, such as linear tubes, measured in various lengths in increments of one foot. up to eight feet. The diameter of the tubes are measures in increments of octaves of an inch. So a T2 is 2/8 of an inch and T8 is 8/8 of an inch or one inch. The larger diameter tubes like T12 are in fact already obsolete and should be phased out. They contain too much Mercury, are less efficient, more prone to leakage of Ultraviolet light and are difficult to handle. Newer linear tubes have a diameter of 5/8 of an inch. Their length is however different from the other tubes (116 cm)
There are also U-bend, circular and compact fluorescent lamps or CFLs. The latter also maybe encapsulated.
Leaking Ultraviolet light is just one of the three concerns which are involved with the use of fluorescent lamps The two other concerns are in case such a lamp breaks. A cut of the glass may cause a problem with bleeding as the phosphor inhibits the coagulation of the blood and the broken lamp will leak Mercury gas if it is still hot or in liquid form if it cooled off. See at the bottom of this writing how to handle these lamps.
A constant effort to lower the Mercury content, is possible through improved technology. The European Union banned incandescent lamps of higher wattages ever since September 01 2009 and fluorescent lamps with content higher than 5 mg per September 01 of 2012. Although the quantities of Mercury in the individual lamps is going down, the mere quantity of the total lamp population is growing rapidly.
The mercury gas in these lamps is ignited when switched on and produces Ultra Violet light. The powder coating of phosphor at the inner wall of the tube filters this light and converts this into white light. Depending of the formula of the coating, the lamp produces light of various color temperatures, measured in degrees KELVIN. Below 4000 degree, the light popularly is called warm white. The higher the degree the term goes to cold white up to daylight around 7000 degrees KELVIN.
Unfortunately most of these lamps, at the end of their life cycle, are dumped in the garbage, where they easily break and contaminate those who are handling the garbage, the soils, the waters and the animals and humans who are at the end of the food chain.
The amounts of Mercury is beyond what should be permissible. Compacts contain some 4 to 10 mg of Mercury, while linear lamps contain up to 40 mg. Get informed how to handle these lamps, especially if one breaks in the house or office, from the site of the EPA. Never handle these compact lamps by the spiral, which is the weakest part. Grab the base instead.
Due to the ever increasing quantities of these lamps used, the trashing of these lamps in the landfills is not a good practice. The Government and private enterprise should work together to provide possibilities to recycle the lamps and inform the users about the necessity to recycle. The manufacturers of the lamps should be obliged to post short guidelines on the packages to inform the general public how to handle these lamps safely.
Another type of lamps, known as solid state lamps with LEDs (light emitting diodes) are in development and the technology is progressing at a high speed. For some applications it is already possible to substitute existing lighting, with even greater energy savings possibilities.
From Left to right: Lit CFL, U-bend Tube CFL, Encapsulated CFL, Fluorescent Tube