UltraVioletC

WHAT IS UV?

The following is intended as a valuable introduction to UV (ultraviolet) for newcomers and enthusiasts alike. Ultraviolet light is that portion of the electromagnetic spectrum that lies beyond the purple edge of the visible spectrum and has wavelengths between 100 and 400 nm. The UV spectrum is further divided into ranges as follows:

Range Name Wavelength Range / nm

UVA 315 - 400
UVB 280 -315
UVC 200- 280
Vacuum UV 100 -200

The UVA range causes sun tanning in the human skin. The UVB range causes sun burning. The UVC range is absorbed by DNA and thus can cause cancer and mutations.

This is also the range that is most effective in inactivating bacteria and viruses. The Vacuum UV range is absorbed strongly by water and air and thus can only be transmitted in a vacuum.

Ultraviolet photons are particularly energetic and when absorbed in molecules can cause bonds to be broken (photochemistry).

UV-C Light Rays

What is a "photon"?

Ultraviolet light (along with all others forms of electromagnetic radiation) comes in discrete energy packets called "photons". The energy of a photon is given by: U = hn = hc/l where h is the Planck constant (6.626755 x 10-34 J s), c is the speed of light (2.997925 x 108 m s-1), n is the frequency (Hz) of the light, is the wave number (cm-1 or m-1) of the light and l is the wavelength (nm or m). Usually photochemical "events" involve absorption of only one photon per molecule.

Why is UV important for the disinfection of water and air?

The portion of the UV spectrum (the germicidal region) that is important for the disinfection of water and air is the range that is absorbed by DNA (RNA in some viruses). This germicidal range is approximately 200 - 300 nm, with a peak germicidal effectiveness at about 260 nm. The mechanism involves absorption of a UV photon by pyrimidine bases (principally thymine) where two pyrimidine bases are next to each other on the DNA chain. The photochemistry involves formation of a dimer that links the two bases together. This causes a disruption in the DNA chain, such that when the cell undergoes mitosis (cell division), the replication of DNA is inhibited.

What are the major commercial applications of UV?

UV has many commercial applications in society. The major ones are: UV disinfection of water and air, UV curing of inks and coatings, UV disinfection of foods, UV-based Advanced Oxidation destruction of pollutants in water and air.

Front Line Medical Workers Taking Extreme Measures To Keep Staff Safe

NBC News’ Alexa Liautaud takes an in-depth look at the extreme measures health care facilities are taking to keep their staff safe during the coronavirus outbreak including a method to sanitize and reuse masks with UV light.

UltraVioletC

UV-C Light Rays

WHAT IS UV?

The following is intended as a valuable introduction to UV (ultraviolet) for newcomers and enthusiasts alike. Ultraviolet light is that portion of the electromagnetic spectrum that lies beyond the purple edge of the visible spectrum and has wavelengths between 100 and 400 nm. The UV spectrum is further divided into ranges as follows:

Range Name Wavelength Range / nm

UVA 315 - 400
UVB 280 -315
UVC 200- 280
Vacuum UV 100 -200

The UVA range causes sun tanning in the human skin. The UVB range causes sun burning. The UVC range is absorbed by DNA and thus can cause cancer and mutations.

This is also the range that is most effective in inactivating bacteria and viruses. The Vacuum UV range is absorbed strongly by water and air and thus can only be transmitted in a vacuum.

Ultraviolet photons are particularly energetic and when absorbed in molecules can cause bonds to be broken (photochemistry).

What is a "photon"?

Ultraviolet light (along with all others forms of electromagnetic radiation) comes in discrete energy packets called "photons". The energy of a photon is given by: U = hn = hc/l where h is the Planck constant (6.626755 x 10-34 J s), c is the speed of light (2.997925 x 108 m s-1), n is the frequency (Hz) of the light, is the wave number (cm-1 or m-1) of the light and l is the wavelength (nm or m). Usually photochemical "events" involve absorption of only one photon per molecule.

Why is UV important for the disinfection of water and air?

The portion of the UV spectrum (the germicidal region) that is important for the disinfection of water and air is the range that is absorbed by DNA (RNA in some viruses). This germicidal range is approximately 200 - 300 nm, with a peak germicidal effectiveness at about 260 nm. The mechanism involves absorption of a UV photon by pyrimidine bases (principally thymine) where two pyrimidine bases are next to each other on the DNA chain. The photochemistry involves formation of a dimer that links the two bases together. This causes a disruption in the DNA chain, such that when the cell undergoes mitosis (cell division), the replication of DNA is inhibited.

What are the major commercial applications of UV?

UV has many commercial applications in society. The major ones are: UV disinfection of water and air, UV curing of inks and coatings, UV disinfection of foods, UV-based Advanced Oxidation destruction of pollutants in water and air.

Front Line Medical Workers Taking Extreme Measures To Keep Staff Safe

NBC News’ Alexa Liautaud takes an in-depth look at the extreme measures health care facilities are taking to keep their staff safe during the coronavirus outbreak including a method to sanitize and reuse masks with UV light.

UltraVioletC

UV-C Light Rays

WHAT IS UV?

The following is intended as a valuable introduction to UV (ultraviolet) for newcomers and enthusiasts alike. Ultraviolet light is that portion of the electromagnetic spectrum that lies beyond the purple edge of the visible spectrum and has wavelengths between 100 and 400 nm. The UV spectrum is further divided into ranges as follows:

Range Name Wavelength Range / nm

UVA 315 - 400
UVB 280 -315
UVC 200- 280
Vacuum UV 100 -200

The UVA range causes sun tanning in the human skin. The UVB range causes sun burning. The UVC range is absorbed by DNA and thus can cause cancer and mutations.

This is also the range that is most effective in inactivating bacteria and viruses. The Vacuum UV range is absorbed strongly by water and air and thus can only be transmitted in a vacuum.

Ultraviolet photons are particularly energetic and when absorbed in molecules can cause bonds to be broken (photochemistry).

What is a "photon"?

Ultraviolet light (along with all others forms of electromagnetic radiation) comes in discrete energy packets called "photons". The energy of a photon is given by: U = hn = hc/l where h is the Planck constant (6.626755 x 10-34 J s), c is the speed of light (2.997925 x 108 m s-1), n is the frequency (Hz) of the light, is the wave number (cm-1 or m-1) of the light and l is the wavelength (nm or m). Usually photochemical "events" involve absorption of only one photon per molecule.

Why is UV important for the disinfection of water and air?

The portion of the UV spectrum (the germicidal region) that is important for the disinfection of water and air is the range that is absorbed by DNA (RNA in some viruses). This germicidal range is approximately 200 - 300 nm, with a peak germicidal effectiveness at about 260 nm. The mechanism involves absorption of a UV photon by pyrimidine bases (principally thymine) where two pyrimidine bases are next to each other on the DNA chain. The photochemistry involves formation of a dimer that links the two bases together. This causes a disruption in the DNA chain, such that when the cell undergoes mitosis (cell division), the replication of DNA is inhibited.

What are the major commercial applications of UV?

UV has many commercial applications in society. The major ones are: UV disinfection of water and air, UV curing of inks and coatings, UV disinfection of foods, UV-based Advanced Oxidation destruction of pollutants in water and air.

Front Line Medical Workers Taking Extreme Measures To Keep Staff Safe

NBC News’ Alexa Liautaud takes an in-depth look at the extreme measures health care facilities are taking to keep their staff safe during the coronavirus outbreak including a method to sanitize and reuse masks with UV light.