Fluorescent lamps work on a very different principle than the incandescent light bulb invented by Thomas Edison in 1879. In the incandescent bulb, electricity heats a filament typically made of tungsten, an element that is resistant to the passage of electricity. The resistance results in high temperature, causing the filament to glow and emit light.
In fluorescent lamps, light is not created by heat. It results from the electrical stimulation of mercury and phosphor atoms in a sealed glass tube. The tube contains a small amount of mercury and an inert gas, typically argon. The tube also is coated on the inside with phosphor powder. As electricity flows through the tube, some of the mercury is changed from a liquid to a gas, releasing ultraviolet light in the process. The phosphor coating serves to convert the ultraviolet light, which our eyes don't register to visible light. Collisions between the electrons and the mercury atoms cause the emission of the ultraviolet energy. The fluorescent powder transforms this ultraviolet radiation into visible light. The ultraviolet wavelength is contained within the lamp by the glass walls of the tube.
NYC SCHOOL AIR QUALITY
The federal Environmental Protection Agency has found the highest levels of leaking PCBs to date in their inspections of New York City schools, specifically at Public School 45 located in Bushwick, Brooklyn. Agency officials said that an inspection of lighting ballasts at the school on Feb. 12, 2012 revealed PCB levels of up to 660,000 parts per million, far beyond the regulatory limit of 50 parts per million. Results from the previous inspections at five other school buildings since January, had found levels of up to 470,000 parts per million.
The likely cause was that capacitors in many of the lighting fixtures had “burned out and completely failed,” officials said. “This allowed the PCB-containing oil to seep through the potting material in almost pure form,” the agency said in a statement. “In most of the fixtures tested in this school the actual casing around the ballasts had also broken, allowing the high concentration of PCBs to contaminate the surface of the ballasts, the fixture housings, the wires and the diffusers that cover the lighting fixture.” The agency said that the higher the concentration in bulk material, the greater the potential for the PCBs’ entering the air, depending on variables like the amount spilled or released and the size of the room. E.P.A. inspectors found that in some cases that old leaking ballasts had been replaced but the new ones were installed in contaminated fixtures that had not been cleaned to remove the leaked material.
“The results give us a new sense of urgency — and certainly they, along with all of the results so far, point to a widespread problem that should and must be addressed by New York City in order to lower any potential risk of long-term exposure,” said Mary Mears, a spokeswoman for the E.P.A. in New York.
FLUORESCENT LIGHT HEALTH and ENVIRONMENTAL CONCERNS
- The UV and IR light from fluorescent tubes and CFL bulbs could present problems in certain types of skin conditions and cancers
- Both mercury and lead exposure are also present
- Buzzing and flicker from fluorescents can cause migraines and seizures
- High heat exposure from lighting causes poor temperature and humidity control which encourages the growth of bacteria and molds
- Poor lighting and shadows may cause lower productivity and preventable mistakes
- Disruption of the circadian clock is linked to several medical disorders like depression, insomnia, cancer, and cardiovascular disease. The 24-hour day/night cycle (circadian clock) affects physiological processes.
- Dramatic increases in the risk of breast and prostate cancers, obesity, and early onset diabetes have mirrored the dramatic changes in the amount and pattern of artificial light generated during the night and day in modern society
- Researchers have concluded that excessive artificial light exposure early in life may contribute to an increased risk of depression and other mood disorders
- Melatonin levels drop precipitously in the presence of excessive artificial light. Melatonin is a hormone that helps to regulate the body’s clock. Melatonin triggers a host of biological activities, possibly including the nocturnal reduction in the body’s production of estrogen
- PCBs do not break down easily and can attach to soil and sediment in water. PCBs build up in fish that eat the sediment and other animals that eat the fish, allowing an accumulation of PCBs that are thousands of time higher than what was in the water or soil. As they accumulate, they become more toxic.
- Due to the way PCBs are structured, they are able to travel far distances in the air, polluting where PCBs were never used directly.
- They are also easily absorbed through skin and inhaled. This increases the likelihood for animals and humans to accumulate toxic amounts.
- Exposure causes many health problems. People exposed to large amounts of PCBs experienced rashes and acne, as well as changes in blood and urine, indicating liver damage.
- Studies done by the Environmental Protection Agency (EPA) of employees with PCB exposure through their work environment found the increased exposure was associated with liver cancer and cancer of the biliary tract.
When did doctors awaken to the dangers of PCBs?
Medical and environmental concern about the long environmental persistence and possible effects on human health of PCBs first arose in the 1960s and 1970s and led to a federal ban on the manufacture of PCBs that was imposed in 1976 under the Toxic Substances Control Act. Unfortunately, PCBs had already become widespread in the environment by that time, and they remain with us today.
How much exposure would start worrying you?
We are most concerned about exposures to pregnant teachers and other adult women of childbearing age in the schools because exposures to even low levels of toxic chemicals during pregnancy have been shown to have the potential to cause injury to the developing fetal brain. There are no safe thresholds for chemical exposure during pregnancy.
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