radiation

Radiation

Is an energy in the form of electro magnetic waves or particulate matter traveling in the air

Ionizing radiation, non ionizing radiation, microwave radiation

Types of radiation that kills microbes

Ionizing radiation

• higher energy electromagnetic waves (gamma) or heavy particles (beta and alpha)

• High enough energy to pull electron from orbit

Non ionizing radiation

• lower energy electromagnetic waves

• Not enough energy to pull electron from orbit, but can excite the electron

Gamma rays or photons, x rays, neutrons

Primary types of ionizing radiations

Ionizing radiation

• example: Gamma rays, x rays, electron beams or higher energy rays

• have short wavelength (less than 1 nanometer)

• Dislodge electron from atoms and form ions

• Cause mutation in DNA and produce peroxides

Non ionizing radiation

• wavelength is longer than 1 nanometer

• Damages DNA by producing thymine dimers which cause mutations

• Used to disinfect operating rooms, nurseries, cafeterias

UVC

• it is almost never observed in nature because it is absorbed completely in the atmosphere

• Germicidal lamps are designed to emit ___ radiation, because of its ability to kill bacteria

• In humans, it is absorbed in the outer layer of the epidermis

• Accidental exposure can cause burns, commonly called “welders flash” and snow blindness a severe sunburn to the face

UVB

• it is typically the most destructive from UV radiation, because it has enough energy to produce to cause photochemical damage to cellular DNA, not enough to be completely absorbed by the atmosphere

• Is needed for the synthesis of vitamin D

• Harmful effects such as: erythema, cataracts, development of skin cancer

UVA

• the most common encountered type of UV light

• Initial exposure to UVA has a darkening effect on the skin

• Atmospheric ozone absorbs very little of this part of UV spectrum

• Is needed by humans for synthesis of vitamin D

Microwave radiation

• wavelength ranges from 1 milimeter to 1 meter

• Heat is absorbed by water molecules

• May kill vegetative cells in moist food