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About UVC


什么是UVC光?

什么是UVC灯?

Ultraviolet (UV) light is a component of the electromagnetic spectrum that falls in the region between visible light and X-Rays.


This invisible radiation includes the wavelength range of 100 nm to 400 nm. UV light can be further subdivided and categorized into four separate regions:

  • 100 nm to 200 nm
    Far UV or vacuum UV (these wavelengths only propagate in a vacuum)

  • 200 nm to 280 nm
    UVC – useful fordisinfectionand sensing

  • 280 nm to 315 nm
    UVB – useful for curing, and medical applications

  • 315 nm to 400 nm
    UVA (or “near UV”) – useful for printing, curing, lithography, sensing and medical applications

UVA versus UVB versus UVC

Most natural UV light is generated by the sun with about ten percent of sunlight being UV and only about three to four percent penetrating the atmosphere to reach the ground. Of the UV radiation that reaches the earth, 95 percent is UVA and five percent is UVB.

没有measurable UVC from the sun reaches the earth’s surface.Because of the spectral sensitivity of DNA, only the UVC region demonstrates significant germicidal properties.

how UVC light affects DNA


How does UVC disinfection work?

作为由多个研究的研究和报告,当生物有机体暴露于深UV光中的200nm至300nm的范围内显然它是由DNA,RNA和蛋白质吸收。

Absorption by proteins can lead to rupture of cell walls and death of the organism. Absorption by DNA or RNA (specifically by thymine bases) is known to cause inactivation of the DNA or RNA double helix strands through the formation of thymine dimers. If enough of these dimers are created in DNA, the DNA replication process is disrupted, and the cell cannot replicate.

bacteria replication infection


Cells that cannot replicate, cannot infect.

It is widely accepted that it is not necessary to kill pathogens with UV light, but rather apply enough UV light to prevent the organism from replicating. The UV doses required to prevent replication are orders of magnitude lower than required to kill, making the cost of UV treatment to prevent infection commercially viable.

UV damage to cells


Ensuring complete inactivation

Generally, in2019新万博appmanbetⅩ , a number of different repair mechanisms have evolved to repair these UV-induced lesions. These mechanisms include direct reversal of the damage by a photolyase (photo reactivation), removing of the damaged base by a DNA glycosylase (base excision repair, BER), incision of the DNA adjacent to the damage by an endonuclease (UV-damage endonuclease, UVDE) or removal of a complete oligonucleotide containing the damage (nucleotide excision repair, NER). As a result, the strategy in UV disinfection has been to provide a sufficiently high dosage to ensure that nucleic acid is damaged beyond repair.


Ensuring complete inactivation

Disinfection is quantified by inactivation rates or Log Reduction Value (or LRV).Log reductionis a simple mathematical term used to express the relative number of live microbes eliminated by disinfection.

Table 1: Log Reduction Value
Microbe Reduction
LRV Factor Percent
1 10 90%
2 100 99%
3 1,000 99.9%
4 10,000 99.99%

UV Dose is the amount of UV radiation a microbe is exposed to and depends on the intensity of UV radiation and exposure time. A number of biological studies have produced widely accepted typical UV dose requirements for most common target microbes in disinfection. For example, to achieve a 3 log reduction (99.9 percent) of B. Subtillus (ATCC 6633) requires a 60 mJ/cm2剂量。

Table 2: UV Dose
Microbe Reduction
Log Reduction Value (LRV) 1 2 3 4
MS2 20.0 42.0 68.0 90.0
枯草芽孢杆菌ATCC 6633 20.0 39.0 60.0 81.0
E. Coli O157:H7 2.0 2.0 2.5 4.0
Staphylococcuss Aureus 3.9 5.4 5.6 10.4

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