If energy needs to be saved, there are good ways to do it.
                                                               Government product regulation is not one of them

Tuesday, July 24, 2012

New Study on CFL UV Radiation

Updated July 26 with comparative spectra also for LED replacement bulbs

The team of Stony Brook researchers reviews the findings of their research. Pictured from left to right (standing) are Marcia Simon, Michael Hadjiargyrou, (sitting) Tatsiana Mironava and Miriam Rafailovich. The images displayed on the screen are of keratinocytes via confocal microscopy which show the results of human skin cells with and without exposure to CFL.

From: Stony Brook University News, July 18

As has widely been reported, a recent study highlights the problem of UV radiation from compact fluorescent bulbs, albeit only at close quarters.
It is therefore recommended that the squiggly tubes are enclosed in capsules for such use, as with the pear shaped CFLs that are available.

From the Daily Mail article 20 July   Edited extracts, highlights

Energy-saving light bulbs can fry your skin, study claims

Energy-saving light bulbs can fry your skin, a new study claims.
Researchers at Stony Brook University in New York State examined the impact of the compact fluorescent bulbs - or CFL bulbs - on human skin cells prompted by a similar study undertaken in Europe.
They discovered that healthy skin exposed to light from the CFLs experienced damage found with ultraviolet (UV) radiation.

'Consumers should be careful when using compact fluorescent light bulbs... our research shows that it is best to avoid using them at close distances and that they are safest when placed behind an additional glass cover' Stony Brook University Professor of Materials Science and Engineering Miriam Rafailovich said.

The scientists tested a number of CFL bulbs from across New York State to determine their UV emissions and the integrity of each bulb’s phosphor coatings.
Results revealed significant levels of UV, which appeared to originate from cracks in the phosphor coatings that were present in all CFL bulbs studied.

They also tested the impact on collagen-producing skin cells and the epidermal cell that generated keratin from the light.
Comparing skin cells exposed to the CFLs with those exposed to incandescent light bulbs, they discovered that only the CFLs damaged skin, the same trauma as sun burnt skin, they found. Incandescent light of the same intensity had no effect on healthy skin cells at all.

The study itself:

The Effects of UV Emission from Compact Fluorescent Light Exposure on
Human Dermal Fibroblasts and Keratinocytes

Tatsiana Mironava, Michael Hadjiargyrou, Marcia Simon, Miriam H. Rafailovich
Article first published online: 20 jul 2012

Compact fluorescent light (CFL) bulbs can provide the same amount of lumens as incandescent light bulbs, using one quarter of the energy.
Recently, CFL exposure was found to exacerbate existing skin conditions; however, the effects of CFL exposure on healthy skin tissue have not been thoroughly investigated.

In this study, we studied the effects of exposure to CFL illumination on healthy human skin tissue cells (fibroblasts and keratinocytes).
Cells exposed to CFLs exhibited a decrease in the proliferation rate, a significant increase in the production of reactive oxygen species, and a decrease in their ability to contract collagen.
Measurements of UV emissions from these bulbs found significant levels of UVC and UVA (mercury [Hg]
emission lines), which appeared to originate from cracks in the phosphor coatings, present in all bulbs studied.

The response of the cells to the CFLs was consistent with damage from UV radiation, which was further enhanced when low dosages of TiO2 nanoparticles (NPs), normally used for UV absorption, were added prior to exposure.
No effect on cells, with or without TiO2 NPs, was observed when they were exposed to incandescent light of the same intensity.

Scotland based lighting designer Kevan Shaw of Savethebulb.org has a particular interest on the effects of CFLs on people with light sensitivity disorders, as he points out in the introduction to his post on this research, extracts:

Frying tonight?

As previously blogged I am assisting the Spectrum Alliance with their campaign to retain incandescent lamps for people with specific photosensitive disorders.
In the course of this I have learned a lot about skin problems caused by CFLs. It seems that such problems are not just confined to specifically photosensitive people. The Daily Mail ran an article on 20 July this year following up on recently published research in the USA. It seems that the light from CFLs has a significantly greater damaging effect on skin than incandescent lamps.

As previously experienced, CFLs do emit UV despite the claims of manufacturers.
Double envelope CFLs do reduce UV emissions considerably and should be used in any situation where lamps are at all close to people like task lighting, table lamps and bedside lights, particularly for the very young and very old whose skin tends to be more sensitive.

Kevan Shaw July 20 , 2012


Some comments elsewhere are taking this quite lightly, even welcoming a bit of sunburn and vitamin D formation.
However, an important point not mentioned is that UVC, one of the UV types emitted, is the most damaging UV source and happens to be blocked by the atmosphere ozone layer when coming from the sun.

An interesting runthrough of UV light can be seen on Digplanet.com, here.

The same source on Fluorescent lamp UV radiation

Fluorescent lamps

Fluorescent lamps produce UV radiation by ionising low-pressure mercury vapour. A phosphorescent coating on the inside of the tubes absorbs the UV and converts it to visible light.

The main mercury emission wavelength is in the UVC range. Unshielded exposure of the skin or eyes to mercury arc lamps that do not have a conversion phosphor is quite dangerous.

The light from a mercury lamp is predominantly at discrete wavelengths. Other practical UV sources with more continuous emission spectra include xenon arc lamps (commonly used as sunlight simulators), deuterium arc lamps, mercury-xenon arc lamps, metal-halide arc lamps, and tungsten-halogen incandescent lamps.

Incandescents have a red shift and relatively low UV output

Incandescent Spectrum
unknown source

CFL lamp spectrum

CFL spectrum

A comparison between light sources
(a CFL is of course a type of mercury vapor lamp)


The sourced Olympusmicro.com site for the last diagram has a good account of lamp technologies and spectra.

Notice how the today's much-hyped LED replacement bulbs ("white LEDs") also have light quality issues, irregular spectrum with blue peaking.. (from http://www.luminousdiy.com/):

LED spectrum

As do the alternative modular Red Green Blue LED bulbs, as seen from the excellent lighting comparative study diagrams on Gluehbirne.ist.org/

As for the issue at hand here,
there is more coverage of UV radiation and other health concerns, with research references and information on related skin and other disorders, on http://ceolas.net/#li18rx

Note that the double envelope CFL recommendation dates back several years from other studies...

BBC article extract, 9 October 2008:

UV light fear over 'green' bulbs

Being too close to energy-saving light bulbs could cause skin reddening because of ultraviolet light emissions, health experts have warned.
The Health Protection Agency (HPA) cautions against being closer than 30cm (1ft) to some compact fluorescent (cfl) bulbs for long.

As a result of testing which revealed the potentially high levels of UV light, the HPA has issued guidelines against people using unencapsulated light bulbs - where the light coil is visible - closer than 30cms to the body for more than one hour a day.

Professor Harry Moseley, Consultant Clinical Scientist at the University of Dundee, said: "We are concerned about risks to patients who have severe light-sensitive skin disorders.
"The small levels of ultra-violet emitted by some low energy light bulbs could be harmful to these patients. I recommend use of lights with a protective shield to absorb the UV."
Experts stress that healthy people are at no risk providing the HPAs advice (above) is followed.

Also a similar EU Commission study 2008, albeit a typically poorly written EU report, seemingly drawing on other studies, and full of conclusions without presenting underlying data evidence (surprise, not).

In December 2009 The Canadian Federal Government Health Department finished a review of CFLs, again mainly relating to UV radiation, but other electromagnetic radiation was also studied.
The report mirrored the UK HPA findings:
"It is recommended that single envelope CFLs [classic tubular type lights] not be used at distances less than 30 cm to avoid any long-term health effects in the general population"

Note a certain irony here...
Double envelope CFLs protecting from UV light also means reducing their ordinary light output still more
There is other irony about CFLs already, eg leave them on, waste energy, switch them on-off, shorten their life...

Basically, bulbs are the wrong format for fluorescent lighting technology, best in long tube form, just like LEDs have natural lighting advantages in sheet form.
The CFL and LED natural advantages are compromised in offering politically pushed incandescent-copying lighting.


Anonymous said...

What you get when you ban old fashioned tho' safe regular bulbs! When are they going to start checking the hyped up LEd light bulbs? JoeG

Lighthouse said...

Yes, showy do-good bans are made by politicians, then problems are discovered with the new less known alternatives.

Compare with industry phasing out products themselves -say radio vacuum tubes. If problems had arisen with transistor radios, the sales of old types would simply have risen again, as a natural market place occurrence

Lighthouse said...

As seen, updated with LED bulb light quality analysis:
Hyped as being "great replacements compared to CFLs", the proponents keep very quiet about the actual light they emit, whether classed as having "warm light like incandescents" or not

chris said...

The different research conducted about the UV radiation has led researchers to take a look at the lighting fixtures we have. They have given us a warning on some of the lighting fixtures that may cause harm to us.

Anonymous said...

So after looking up "ultraviolet" on wikipedia and looking at the table of wavelength (in nanometers) vs. the type of UV (UVA, UVB, UVC), the graphs you've posted do seem to *imply* that LED lights emit less UV of all types than even incandescents. Of course they also show that CFLs are the worst. I'm a bit disappointed that the graphs on your page stop at 400 nm, as this is the upper range of all harmful UV light, so I say "imply" because I'm extrapolating below 400nm after looking at your curves. (UVA is 400-315nm, UVB is 315-280nm, UVC is 280-100nm.) The graphs are an excellent comparison of the visible light characteristics. Please update to include UV characteristics!

Lighthouse said...

Thanks zeroimpedance, excuse late reply
yes I notice 400nm is a common cut off point...
google image search shows alternative cfl spectral graphs although at quick glance none as far as 100nm in a clear way
e.g. cfl

and led

Anonymous said...

I would love to know what type of double envelope cfl bulbs offer the most protection from UVA UVB and UVC rays? There are different types available. I have seen plastic (shatter resistant) and glass. Also some of the glass double envelopes are more frosted than others. The double envelopes in the higher watt bulbs (75 watt equivalent) seem to be almost translucent. Would they offer much protection?

Lighthouse said...

@ Anonymous re double envelope CFLs

I haven't checked the issue, but the researched need for double envelopes
(UK and Canada) is about such need for regular or lengthy use within a foot distance...
"it is recommended that single envelope CFLs [classic tubular type lights] not be used at distances less than 30 cm to avoid any long-term health effects in the general population"

The linked research reports may have more on that in links or subsequent follow-ups:
See the UV radiation section here

Unknown said...

The cfl bulbs are the best solution for energy saving and long lasting. we can protect our environment by using this products. Visit for other uv products.

Lighthouse said...

Thank you Alejandra
Hidden in ventilation ducts may indeed be a good place for them ;-)

Actually, an interesting disinfecting use you mention, though it shows the dangers of UV light radiation as well.

A main point in this blog is that all lighting forms have different advantages for different situations.
Banning incandescents is therefore wrong for the specific advantages they have, as described on the page linked on the left, and website links.

Unknown said...

UV Light Air Purifiers for Better Health

What you can’t see can truly hurt you. Indoor air quality is a growing concern for most homeowners, as more and more people spend the vast majority of their time indoors. Indoor air can actually be more polluted than outdoor air.
Ultra violet light, such as that found in a UV light air purifier, can kill these toxic substances in your home, greatly reducing allergens, killing germs and enhancing your family’s health. Standard air purifiers rely solely on the purifying unit to clean the air as it circulates through. This is not an effective means for guarding your home against microbial substances. A UV light air purifier not only captures these irritating microorganisms, but it also destroys them once they come into contact with the ultra violet light.
We should be concern about our heath and I think it is a great solution to use uv light for air conditioning.

Unknown said...

Hey I my friends I tell you something can you give me answer. Radiation handphone also potentially cause cancer, brain tumors, Alzheimer's, Parkinson's, fatigue (too tired), and headache. Although the results of research conducted by experts, some being menyabutkan, that mobile phone radiation can cause cancer and abnormalities. However, some have claimed that mobile phone radiation is not related to cancer. Regardless of what is right or wrong of course we should need to be alert and anticipate.
Dangerous radiation

Zach said...

I am one of the people with high sensitivity to these spiral CFL bulbs. I can tell you, the problem isn't just when I sit close to one. If the room I am in is illuminated with several CFL bulbs, I cannot be in that room. My skin starts to feel irritated and sore, like it is being roughed up. If I am sitting right under one of these CFLs in a restaurant, I can feel it after only 10 minutes. My eyes also feel sore for many hours afterwards, it's like snow blindness.

What I can tell you is that an extra layer of glass makes a big difference. I can tolerate siting in a restaurant with CFL flood lights, where the inner spiral is inside the outer glass bulb.

Just in case you were wondering, I don't have a huge problem being out in direct sunlight, as long as it isn't for many hours. I am also sensitive to bare exposed fluorescent tubes, though I don't have too much of a problem if they are covered by light diffusor panels, just as long as I am not under them the whole day. I am still 2-3 times more sensitive to a spiral CFL than to an exposed fluorescent tube.

Although I may be more sensitive than most, I can't imagine all this extra UV exposure will be good for everyone else either. There are different types of UV, and CFLs leak out the damaging type.

Decorating lamp said...

Congratulations about this comprehensive information about UV Radiation from lamps.

Thanks a lot!

Anonymous said...

Light "Quality" is being defined here by white hot metal.

Why not fire? Or the spectra of the sun, or the spectra of the sun as seen underwater - since our eyes evolved for underwater seeing.

How about defining it in terms of the spectra of the Red Giant star Regulus, or the spectra of light as seen from the vantage point of a forest floor?

Whenever you see "freedom" in front of something you just know that it couldn't be sold in any other way.

It is a sales pitch that appeals to the gullible and the uneducated.

Lighthouse said...

Thanks Vendicar...
the broad spectrum light quality of incandescents is well known - as for sales pitching that would be exactly what I would be avoiding on a blog like this ;-)