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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:
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.
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.
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
- 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
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.
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
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.
1. LED Lighting and Sustainability
Modern LEDs have a luminous efficacy of approximately 170lm/W in comparison to 10-15lm/W for incandescent lamps and 60-80lm/W for a fluorescent tubes. This results in more light per watt of input power and hence fewer required light fittings for a given area. The efficient lumen per watt ratio of LEDs means a significantly reduced electrical lighting load for a building can be achieved resulting in lower carbon footprint and greenhouse gas (GHG) emissions. The ease at which LED fittings can be further controlled, i.e. via presence detectors or photocells and to which they can be dimmed enable them to offer further energy saving features and help contribute to a sustainable future.
LED light emission is directional and can emit light for 180 degrees, compared to fluorescent and discharge lamps, which emit all 360 degrees around the lamp, This directional feature is typically an advantage because light is usually desired over a target area, and so LEDS emit less glare, overspill and uplight / sky glow pollution, features that further contribute to energy efficiency by reducing waste light. You can read more about the impact of directional lighting by learning about a measurement called “useful lumens” or “system efficiency.”
LEDs have virtually zero maintenance costs and the frequency with which lamps have to be changed out is by far the best on the market. Fluorescent bulbs require regular re-lamping and ballast replacement in addition to the labour cost to monitor and replace ageing or expired components.
1.2 Waste Reduction
Fluorescent and other discharge lighting types uses environmentally hazardous chemicals, such as Mercury, which can be leaked into the environment if the lamps break. LED luminaries have no such hazardous components and present no danger to the environment if broken.
Furthermore, LEDs have a much longer operating life, up to six times that of fluorescents tubes, and so each LED fitting would negate the production and disposal of six equivalent fluorescent fittings, providing less environmental impact over its life. LED Lamps can also be recycled.
Fluorescent lights primarily produce UV radiation. They generate visible light because the lamp is coated with a layer of phosphor which glows when it comes into contact with UV radiation. Although most UV radiation stays within the lamp, some does escape into the environment which can hazardous to skin and the eyes over time, while also biologically harmful to cell reproduction.
Finally, lower power results in lower current, and lower current means less copper required in the cables supplying the LED circuits, relieving demand on the earths copper resources.
LED Lamps last longer than any light source commercially available on the market. Lifespans are variable but typical values range from 25,000 hours to 200,000 hours or more before a lamp or fixture requires replacement. Fluorescent lights have good lifespan relative to other conventional lamps but not compared to LED. Typical fluorescent lifespan values range from 7,000 hours to 15,000 hours before a lamp requires replacement. Note: sometimes fluorescent lights need to be changed out before the end of their useful life to pre-empt serious degradation effects like flicker or changing light color (turning pink).
LED lighting has relatively high initial costs and low lifetime costs. The technology pays the investor back over time (the payback period). The major payback comes primarily from reduced maintenance costs over time (dependent on labour costs) and secondarily from energy efficiency improvements (dependent on electricity costs). Fluorescent lights are relatively cheap to purchase but relatively expensive to maintain. Fluorescent bulbs will likely need to be purchased several times and the associated labour costs will need to be paid in order to attain the equivalent lifespan of a single LED light.
2. LEDs Light and Heat (IR) / Ultra Violet (UV) Emissions
LED luminaires convert more than 50% of their total input power into visible light, a significant improvement on incandescent and fluorescent luminaries which only convert approximately 10% and 20% respectively. The resulting (wasted) energy is emitted in mainly infra-red (Heat) and Ultra-Violet (UV) spectrums. Heat emission from incandescent and fluorescents lamps add to the overall heat load in the building increasing the mechanical cooling requirement and in turn the electrical building load, GHG emissions and carbon footprint. Efficient LED lamps means significantly less heat emission per lamp and less waste heat offloaded onto the building A/C cooling system to deal with.
LEDs produce a very narrow spectrum of visible light without the losses to irrelevant radiation types (IR or UV) associated with conventional lighting, meaning that most of the energy consumed by the light source is converted directly to visible light. Fluorescent lights actually produce primarily UV radiation. They generate visible light because the lamp is coated with a layer of phosphor which glows when it comes into contact with UV radiation.