Fluorescent lamps have been suggested to affect human health in various ways.
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Nocturnal exposure to light in the short wavelength ranges (below 530 nm) generated by some fluorescent lamps may interfere with mammalian circadian rhythms due to its suppressing effect on melatonin production. Suppression of melatonin has been linked to cancer in some studies.
The ability of fluorescent lamps to suppress melatonin in humans after nocturnal light exposure is strongly dependent on the color temperature of the lamp. While lamps with daylight color (6500 K) can significantly suppress melatonin, warm white lamps (2700 K or 3000 K) have a significantly lower effect on melatonin suppression. Cool white colors (color temperature of 4000 K) have a moderate effect on melatonin suppression. Therefore warm white lamps are recommended for use at nighttime in order to prevent melatonin suppression.
Flicker effects
Fluorescent lamps with magnetic ballasts flicker at a normally unnoticeable frequency of 100 or 120 Hz. This flickering can cause problems for some individuals with light sensitivity. Such lamps are listed as problematic for some individuals with autism, epilepsy, lupus, chronic fatigue syndrome, Lyme disease, and vertigo. Newer fluorescent lights without magnetic ballasts have essentially eliminated flicker.
The normally unnoticeable 100-120 Hz flicker from fluorescent tubes powered by electromagnetic ballasts are associated with headaches and eyestrain. Individuals with high flicker fusion threshold are particularly affected by electromagnetic ballasts: their EEG alpha waves are markedly attenuated and they perform office tasks with greater speed and decreased accuracy. Ordinary people have better reading performance using high-frequency (20 kHz - 60 kHz) electronic ballasts than electromagnetic ballasts, although the effect was large only for the case of luminance contrast.
Early studies suspected a relationship between the flickering of fluorescent lamps with electromagnetic ballasts and repetitive movement in autistic children. However, these studies had interpretive problems and have not been replicated.
Compact fluorescent lamps (CFL) are driven by electronic ballasts which operate in the range of 25-60 kHz, which far exceeds the human ability to perceive flicker.
Ultraviolet radiation risk
Some fluorescent lamps emit ultraviolet radiation. The Health Protection Agency of the United Kingdom has conducted research concluding that exposure to open (single envelope) compact fluorescent lamps (CFLs) for over 1 hour per day at a distance of less than 30 cm can exceed guideline levels as recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP).
Not all open CFLs produce significant UV emissions. However, close proximity to bare skin can result in exposure levels similar to direct sunlight. The Health Protection Agency of the United Kingdom recommend that in situations requiring close proximity to the light source, open (single envelope) CFLs be replaced with encapsulated (double envelope) CFLs.
In 2009, Natural Resources Canada released a report describing the possible UV exposure from several types of lamps. The report states that at 3 cm distance, the recommended daily exposure to ultraviolet radiation for skin and eye damage (if looking directly at the lamp) was attained between 50 minutes and 5 hours depending on the type of lamp. The report observes that such a close distance is unlikely in actual use. The report also states that most bare-spiral lamps tested gave off more UV than the 60 watt incandescent lamp tested, but that the encapsulated (double envelope) CFLs emitted less UV radiation. At 30 cm distance, the recommended maximum daily exposure was attained between 3 hours and 6 hours, with little difference between the studied 60 Watt incandescent lamp and any bare-spiral CFL. The report states that the threshold limit values used represent otherwise healthy individuals who are not experiencing any hypersensitivity conditions or exposed to substances that increase UV sensitivity. Outdoor sunlight can supply the maximum recommended daily UV exposure in 20 to 100 minutes.
SCENIHR study and report
The Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) in 2008 reviewed the connections between artificial light and numerous human diseases, including:
- Ultraviolet radiation emitted by fluorescent lighting can increase an individual's exposure to carcinogenic radiation by 10 to 30 per cent per year, with an associated increased probability of contracting squamous cell carcinoma by 4 percent.
- Melanoma has been shown to not be affected by CFLs through normal use.
- The constituent high-energy visible light (some blue light) of CFLs can aggravate retinal diseases in susceptible people, but it is unlikely to occur.
- The report states that "people with autism or Asperger's syndrome have reported problems which they attributed to fluorescent lighting and any deleterious effects on sufferers of autism or Asperger Syndrome from CFLs cannot be dismissed.
- The inner-ear condition Ménière's disease can be aggravated by flicker. Sufferers of vertigo are recommended to not use fluorescent lights.
- Polymorphous light eruption is a condition affecting the skin thought to be caused by an adverse reaction to ultraviolet light. Its prevalence across Europe is 10-20% of the population. Artificial light sources may provoke the condition, and CFLs have been shown to produce an eruption.
- Chronic actinic dermatitis is a condition where a subject's skin becomes inflamed due to a reaction to sunlight or artificial light. Its prevalence in Scotland is 16.5 per 100,000 population. There is evidence that CFLs worsen the condition.
- The autoimmune disease lupus is exacerbated by CFLs.
- There is evidence that actinic prurigo is worsened by CFLs. This disease affects 3.3% of the general population.
- 3.1% of the population suffer solar urticaria, a skin disorder affected by ultraviolet light. Some patients are directly affected by CFLs.
- Phytophotodermatitis may be aggravated by the additional levels of ultraviolet light emitted by CFLs.
- Patients undergoing photodynamic therapy are at additional risk of adverse photosensitive reactions caused by CFLs.
- Self-reporting suggests that 21% of chronic fatigue syndrome patients experience sensitivity to light but there have been no studies into the association between chronic fatigue syndrome and CFLs.
- One cause of cataracts is exposure to ultraviolet light. Provided the level of UV emission from lamps is within safe limits, and the lamp a sufficient distance away from the individual, there should be no increased risk of developing cataracts.
- Photophobia is a symptom of excessive sensitivity to light which affects 5 to 20% of the population. No studies have been conducted into the effect of CFLs on sufferers of photophobia but there is the possibility for CFLs to affect sufferers.
- There is evidence that flicker can cause seizures in patients with photosensitive epilepsy, but there has yet to be any evidence to date attributing seizures to compact fluorescent lamps.
- Self-reporting suggests fluorescent lamps aggravate dyslexia, but tests show that dyslexic patients are unable to detect flicker emanating from light sources. This opinion was updated by SCENIHR in 2012, with no significant changes from the opinion of 2008.
Electromagnetic radiation risks
The World Health Organization's IARC categorizes EMF and radiofrequency exposure as class 2B possibly carcinogenic. Like other devices that are dependent on electricity for their functions, the electronic ballasts in fluorescent lamps emit electric and magnetic fields in the low-frequency range (the distribution frequency 50 Hz and possibly also harmonics thereof, e.g. 150 Hz, 250 Hz, etc. in Europe). Some fluorescent bulbs emit high-frequency fields (30-60 kHz). Electric fields of this intensity have been associated with biological effects. The effects of these can be reduced significantly by maintaining an appropriate distance from them.
The Assessment of EM Exposure of Energy-Saving Bulbs & Possible Mitigation Strategies study has shown that worst-case exposure in bulbs tested is within the International Commission on Non-Ionizing Radiation Protection (ICNIRP) limits, the majority of which with large margins.
The Seletun international scientific panel has called for all new CFLs to be fitted with filters, since studies also show that CFLs conduct voltage transients and harmonics ("dirty electricity") onto the wiring and that these can have biological effects, especially as regards diabetes and cancers.
Mercury
Fluorescent bulbs contain mercury, a toxic substance. The United States Environmental Protection Agency (EPA) provide safety guidelines for how to clear up a broken fluorescent bulb. Mercury can be harmful to children and developing fetuses, so children and pregnant women should avoid being in the area whilst a broken bulb is cleared up.
Bulbs which have reached the end of their life should not be disposed of in normal trash, as this may release the mercury into the environment if the bulb is damaged. Several countries have specialised recycling or disposal systems for fluorescent bulbs, e.g. US bulb recycling.
According to the U.S. Environmental Protection Agency (EPA), the amount of mercury contained in a compact fluorescent lamp (CFL) is approximately 1% of the amount found in a single dental amalgam filling or old-style glass thermometer. The U.S. EPA also states that using energy-efficient CFLs reduces demand for power, which reduces the amount of coal burned by power plants and hence reduces the amount of mercury emitted from coal fired power plants.
Other conditions associated with fluorescent light
In rare cases individuals with solar urticaria (allergy to sunlight) can get a rash from fluorescent lighting. Very photosensitive individuals with systemic lupus erythematosus may experience disease activity under artificial light. Standard acrylic diffusers over the fluorescent lamps absorb nearly all the UV-B radiation and appear to protect against this.
One paper suggested that in rare cases, fluorescent lighting can also induce depersonalization and derealization; subsequently, it can worsen depersonalization disorder symptoms.
The charity Migraine Action Association reported concerns from members that CFL bulbs can cause migraines, and there are many anecdotal reports of such occurrences.
Source of the article : Wikipedia
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