Chanakya IAS Academy Blog

The article discuss about the findings of a recent report about the disadvantages of using LED.

  • Excessive blue light emitted by light emitting diodes (LED) can adversely impact human health, according to a report recently released by the American Medical Association (AMA) Council on Science and Public Health.
  • The report looked at LED street lighting on U.S. roadways.
  • LED lighting has several advantages:
    1. LED are very energy efficient.
    2. Long Lifetime - 50,000 hours or more if properly engineered.
    3. Rugged - LED’s are also called Solid State Lighting (SSL) as they are made of solid material with no filament or tube or bulb to break.
    4. No warm-up period - LED’s light instantly – in nanoseconds.
    5. Not affected by cold temperatures - LED’s “like” low temperatures and will startup even in subzero weather.
    6. Directional - With LED’s you can direct the light where you want it, thus no light is wasted.
    7. Excellent Color Rendering - LED’s do not wash out colors like other light sources such as fluorescents, making them perfect for displays and retail applications.
    8. Environmentally friendly - LED’s contain no mercury or other hazardous substances.

Disadvantages of LED:

    1. The excessive blue light it emits can be harmful. The human eye perceives the large amount of blue light emitted by some LEDs as white.
    2. Blue light directly affects sleep by suppressing the production of the hormone melatonin, which mediates the sleep-wake cycle in humans.
    3. Compared with conventional street lighting, the blue-rich white LED street lighting is five times more disruptive to sleep cycle.
    4. Evidence available suggests a long-term increase in the risk for cancer, diabetes, cardiovascular diseases and obesity caused by chronic sleep disruption due to exposure to blue light.
    5. The excessive blue wavelength contributes to glare effects as a result of larger scattering in the human eye.
    6. Contrary to the popular notion that bright LED lighting increases road safety, the report says discomfort and disability glare caused by unshielded, bright LED lighting negatively impacts visual acuity, thus “decreasing safety and creating road hazards”.
    7. Glare forms a veil of luminance that reduces the contrast, thus in turn reducing the visibility of a target.
    8. The report also notes that unshielded LED lighting causes papillary constriction, leading to “worse night-time vision between lighting fixtures.” Intense blue spectrum can even damage the retina.
  • Unless blue-light emission from 4,000K LED street lighting is restricted, retrofits using these lamps could result in 2.5 times increase in lighting pollution.

Question: LEDs offer a huge variety of benefits but at the same time they cannot be viewed as the optimum solution for every lighting-related application. Examine.

Suggested Approach

  1. The benefits of LED.
  2. The disadvantages of LED.
  3. The way forward.

Link: http://www.thehindu.com/sci-tech/technology/not-all-is-bright-and-shining-with-led-light-study/article8761475.ece

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