BLOCK 6: NON-IONIZING RADIATION - Unit 12: Ultraviolet/Infrared Radiation (complete)

Question 1

The major source of naturally occurring UV radiation in the environment.

Answer 1

SUN

Question 2

What are the 3 factors that affect the amount of UV radiation in the environment?

Answer 2

–> HEIGHT OF THE SUN
–> ALTITUDE
–> OZONE DEPLETION

Question 3

The amount of UV radiation is greatest when the sun is directly _______________.

Answer 3

OVERHEAD

Question 4

The UV radiation spectrum is divided into _____ major components that induce significantly different biological effects.

Answer 4

3

Question 5

These exposures damage the skin first, leading to a perfect path for the greater damaging effects, leading to cancer.

Answer 5

UVA: LONG WAVE

Question 6

This UV light controls the growth of bacteria, mildew, algae, slime, etc. and is commonly used in meat processing plants and other food storage systems and in the walls, ceiling, and floor of a cool room. The area is bombarded by UV light and acts as a germicidal agent, thus maintaining a fresh-smelling area.

Answer 6

UVC: SHORT WAVE

Question 7

The most dangerous type of UV radiation and is responsible for sunburn, suntan, skin aging, skin cancer, and eye damage.

Answer 7

UVB: MIDDLE WAVE

Question 8

The __________ is the principle organ of concern from UV radiation exposure.

Answer 8

SKIN

Question 9

The penetration into the human tissue is limited, but there are two factors that increase skin damage:

Answer 9

WAVELENGTH and SKIN PIGMENT

Question 10

Any UV wavelength above _______________ (UVA and UVB) has the potential to damage skin, though pigmented (tan or dark) skin is less susceptible to burns or other complications.

Answer 10

0.3 µm

Question 11

Exposures to UV radiation at this point may cause some immediate effects which include:

Answer 11

 Erythema – reddening of the skin
 Increased pigmentation – more colored areas
 Darkening of pigment – melanin
 Changes in cellular growth – e.g., possible cancer

Question 12

The most common sign of overexposure to UV radiation is _______________.

Answer 12

PHOTOKERATITIS

Question 13

Infrared radiation basically comes from any source that generates __________.

Answer 13

HEAT

Question 14

____________________ are considered the most common source of hazardous IR radiation.

Answer 14

HEATED METALS

Question 15

The skin is less sensitive to IR than the eyes because the skin is normally able to _______________ the heat load imposed by IR.

Answer 15

DISSIPATE

The reason skin can dissipate heat load is because of:

 Increased blood circulation which helps to dissipate the heat generated.
 The production of sweat that opens pores to let out heat.
 Ambient air movement allows evaporation of perspiration generated by heat.

Question 16

Some control methods to protect from UV and IR radiation include:

Answer 16

 Welding curtains
 Eyeglasses, goggles, and/or plastic face shields (for UVA, UVB, and UVC)
 Protective clothing
 Sunscreen creams/lotions
 Short durations of exposure
 Welding helmets/goggles (special lens)
 Time, distance, shielding