UltraViolet

1    UltraViolet (UV) Radiation and Artificial lighting:

When Ultraviolet radiation, commonly known as UV rays, are mentioned, people are likely to think firstly of their holidays in the sun or reminisce of a past sunny summer, but UV rays have been present in every room in our homes and workplaces for years in artificial fluorescent and incandescent lighting.

 

2    Ultraviolet Radiation / Rays:

2.1    What are Ultraviolet / UV rays?

UV rays are a form of electromagnetic radiation that propagate through space, and belong in the same family as x-rays, micro-waves, radio waves, infra-red (heat) and visible light rays. Visible light is the only part of the spectrum that humans can ‘see’ as our eyes have evolved to adapt to this light, primarily due to its abundance on the surface of the earth. UV rays are alongside visible light on the spectrum but have shorter wavelength. (Wavelength is the distance between successive waves) The spectrum is divided into different bands based on their properties. UV rays exists from approximately 100nm to 400nm.

2.2    Where does UV radiation come from?

The primary source of UV radiation on earth is from the sun. It is also emitted naturally from incandescent effect in halogen lamps and is created inside fluorescent lamps before the phosphor coating changes it to visible light that we see. UV is also emitted in tanning booths and some welding arcs.

 

2.3    How can I detect UV rays?

UV radiation is just out of the range of the human eye and so is invisible. Special detection equipment is required to detect / measure UV rays. The after effect of over-exposure to UV can be seen and felt by the reddening and soreness of the skin known as sunburn.

 

3    UV Rays and the Environment

3.1    What are the harmful effects of UV radiation to humans?

  • Causes direct DNA damage to skin cells resulting in ‘sunburn’.
  • Ages skin prematurely resulting in leathery and wrinkly skin in later life, if subject to long term exposure.
  • Causes Skin cancer: Research shows that as many as 90% of skin cancers are due to UV radiation.
  • Can cause eye damage and cataracts in later life, if subject to long term exposure.
  • Can trigger/exasperate skin disorders such as Lupas flares: an auto-immune system disease whereby the immune system attacks healthy cells, solar urticaria: a skin disorder affected by ultraviolet light and Phytophotodermatitis a skin disorder hyper sensitive to UV light.

Are there other harmful effects of UV radiation to the environment?

  • Weakens Plastics
  • Fades Colours on fabrics, paintings and furniture.
  • Damaging to plants and animals

 

3.2    If UV rays are so close to visible light on the spectrum, how are they harmful to human skin and eyes?

All electromagnetic radiation, including UV rays, increase in energy as the wavelength gets shorter. UV rays exist through a range of wavelengths from 100nm to 400nm, shorter than visible light which exists from 400nm to 700nm range. UV rays that have wavelengths closer to the visible light end of spectrum, (sometimes referred to as ‘near UV’) have less energy to cause damage than UV rays further away . To help classify the difference, scientists have divided the UV range into three bands

UVA-315-400 nm – The most penetrating band of UV, but with the least energy to cause damage. Accounts for 98% of UV radiation reaching the earth’s surface. Causes tanning and can initiate skin cancers with prolonged exposure.

UVB – 280-315 nm – The most damaging band of UV to humans. Accounts for 2% of UV radiation reaching the earths surface. Causes sunburn and skin cancer.

UVC – 100-280 nm- The most potentially damaging band of UV. Fortunately this band is easily blocked by the earths atmospheres and doesn’t reach the surface.

 

3.3     What band(s) of UV radiation are fluorescent lighting and artificial lighting emitting in to the surrondings?

An investigation by Sayre in 2004 yielded the following;

“It was  found that all lamps tested emitted appreciable levels of UVA and UVB, and several even emitted UVC. “ 

(Sayre RM, Dowdy JC, Poh-Fitzpatrick M. Dermatological risk of indoor ultraviolet exposure from contemporary lighting sources. Photochem Photobiol. 2004;80:47–51 

 

3.4    Is UV from fluorescent lighting damaging health?

Investigations into the area yields conflicting results, some could be accused of elevating the risks, other could be accused of downplaying them.

“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 carcinomaby 4 percent.”

(Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) , 2008) 

“A 1993 study in the US found that ultraviolet exposure from sitting under fluorescent lights for eight hours is equivalent to just one minute of sun exposure.”

(Nema, Ultraviolet radiation from Fluorescent Lamps, 1999 referencing C.Lytle, 1993)

There is no disputing that fluorescent lighting fixtures (and to a lesser extent incandescent fixtures) emit UV radiation, especially if the tubes / lamps are exposed or cracked. There is also no dispute that UV rays from lighting are an unwanted side effect from fluorescent lighting with little to contribute positively to the surroundings. Where dispute does arise is whether the level of UV omitted from these sources is harmful. People who have worked for years under fluorescent lighting may report no adverse effect but studies which downplay the level of radiation may not take into account long term exposure or people with photosensitive skin. It may be difficult to prove problems in later life such as eye cataracts and aged skin as being attributed to fluorescent UV radiation.

4    What can be done if I’m worried about UV radiation from Fluorescent lamps / fixtures?

Consider switching to LED lamps / fixtures. Modern LEDs lamps do not emit UV radiation as the produce light in a different way to fluorescents and incandescent lamps.

If existing fixtures are not covered by a diffuser, or your can see the lamps directly, the UV rays may be more prevalent and warrant quicker action.

For people with photosensitive skin it would be advised to replace fluorescent lights with LED.

For bedhead lights, local / task lighting or lighting where people are in closer proximity to the fluorescent lamp, it would be advisable to replace fluorescent lamps with LED.

In areas with indoor plants, increase their survival chances by switching to LED.

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