Ultraviolet, Infrared, and the Skin

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Ultraviolet, Infrared, and the Skin

• By Matt McCahan

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What do the suns radiation, Infrared,
Ultraviolet, and the skin have in common?

• The sun radiates (about 6000K surface temp), so
  about half of solar energy arriving at the earth
  is in the infrared with most of the rest in the
  visible part of the spectrum, and a relatively
  small amount in the ultraviolet
• The radiation from all of these (sun, UV, IR) has
  adverse effects on living cells (skin)

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Electromagnetic Radiation

• Can be visualized as electric and magnetic waves
  oriented at right angles, and propagating in a
  direction mutually perpendicular to both fields.
• Ex. Sun

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Spectrum Graph
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Ultraviolet (UV) Radiation

• Electromagnetic radiation of wavelengths shorter
  than those of visible light but longer than those
  of X-rays
• Most active part of the spectrum for photodamage
  or damage from light

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3 Groups of UV Radiation

• UVC (less than 290nm) screened by the earths
  ozone layer. Thus the worry of the ozones
  depletion
• UVB (290-320nm) screened by glass, part of UV
  that causes sunburn
• UVA(320-400nm) makes up over 90 of UV radiation
  that reaches earths surface due to atmospheric
  screening

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Infrared (IR) Radiation

• Electromagnetic radiation of a wavelength longer
  than visible light but shorter than radio waves
• Although it cant be seen, humans can detect it
  as heat
• All objects with a temp. above absolute zero emit
  radiation. The precise wavelength of this
  radiation depends on the temp. of the object.
  Humans with body temperatures of roughly 40
  degrees C or about 310 degrees K emit in the
  infrared portion of the spectrum

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OZONE

• In the stratosphere, the region of atmosphere
  between about 10-50km (6-30 miles) above the
  Earths surface, ozone plays a vital role
• Ozone absorbs solar radiation in the UV and
  visible part of the spectrum
• Depletion of the protective ozone layer by
  escaped refrigerant gases called
  chlorofluorocarbons (CFCs) is a matter of great
  concern

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Ozone Layer
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Solar Backscattering Ultraviolet Instrument
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Ozone Layer
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International Scientific Assessments of Ozone
Depletion
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The Skin

• As we get older our skin naturally begins to
  wrinkle and sag
• 80 of these signs of aging are due to exposure
  to the sun
• A very important change in the skin occurs in the
  dermis (upper layer) where sunlight causes the
  elastin fibers, which should be straight, to
  become thickened and tangled and progress into a
  single clump of inelastic material
• This process is known as elastosis
• This degradation of the elastin fibers is not
  seen in skin protected from the suns harmful
  effects

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Pigment Changes

• In addition to wrinkles, many of the pigment
  changes seen with aging skin are related to sun
  exposure
• UV exposure is cumulative and may take years to
  be visibly noticed

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What is tanning?

• Tanning is the skins response to ultraviolet
  light
• Tanning is a protective reaction to prevent
  further injury to the skin from the sun
• However, tanning CANNOT prevent skin cancer

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How much is too much?

• Planning for an amount of time in the sun to
  protect against sunburn is good, but its the
  years of daily sun exposure that adds up the most
• Only 10 min. of sun a day adds up to over an hour
  of unprotected sun exposure in just one week

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Todays Generation

• Because children and teenagers spend so much time
  out in the sun, it is estimated that as much as
  80 of UV-induced photoaging (radiation related
  damage) may occur with the first 20 years of life

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Skin Cancer

• Like other cancers, skin cancer is a combination
  of genes and the environment
• The sun (environment) is the leading cause of
  skin cancer
• Develops on the face, neck, and arms
• More common in the southern areas of the U.S.
• Appears to be hereditary and occurs more
  frequently to those with fair complexions

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Cancer

• Skin cancer is a disease of cells
• Normal growth and repair of tissues takes place
  in an orderly fashion
• When cell division is not orderly, abnormal
  growth occurs

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Other Causes

• X-Rays
• Trauma
• Certain Chemicals
• Dentists frequently develop skin cancer on their
  hands from working with X-rays

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Hints for Sun Protection

• Minimize sun exposure during 10a.m.-3p.m.
• Apply sun-screen, and then reapply frequently
• Apply during high altitude activities such as
  hiking and skiing. (At high altitudes there is
  less atmosphere to absorb the suns rays, thus
  the risk of burning is greater.

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More Hints

• The sun can be just as damaging on hazy or cloudy
  days
• Photosensitivity can cause side effects on
  certain medication and cosmetics
• Be aware of reflective surfaces! Sand, snow and
  concrete can reflect more than half of the suns
  rays onto your skin
• Avoid tanning parlors. The UV light emitted in
  tanning booths can cause sunburn, premature
  aging, and increases the risk of skin cancer

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Conclusion

• Knowledge of prevention increasing
• Personal- sun glasses, sun tan lotion, limit
  exposure
• Environmental-concern about the depletion of the
  ozone (Avoid using CFCs)
• Best Weapon- KNOWLEDGE