In an age where hygiene, cleanliness and infection control are more crucial than ever, ultraviolet germicidal irradiation (UVGI) using UV-C light has offers a reliable, chemical-free method to disinfect air, water, and surfaces. UV-C light, typically emitted at a wavelength of 254 nanometers, disrupts the DNA or RNA of microorganisms, rendering them inactive and unable to replicate.
Why UV-C light?
UV-C disinfection offers a host of advantages:
- Chemical-free: Leaves no residue or toxic byproducts.
- Broad-spectrum efficacy: Effective against bacteria, viruses, molds, and spores.
- Rapid action: Microbes can be inactivated in seconds to minutes depending on exposure.
- Scalable and versatile: Can be used in a range of settings including hospitals, care homes and food processing facilities.
- Ease of use, low running and maintenance costs.
Scientific basis of UV-C disinfection
The effectiveness of UV-C light is measured in log reductions, representing the percentage of microorganisms eliminated:
- 1-log = 90% reduction (D90)
- 2-log = 99% reduction
- 3-log = 99.9% reduction
- 4-log = 99.99% reduction
- 5-log = 99.999% reduction
The dose (or fluence) of UV-C light is measured in joules per square meter (J/m²). Each microorganism has a different sensitivity to UV-C, requiring a specific dose to reach desired log reductions. When looking to target multiple pathogens, you should target the one with the greatest dose requirement to ensure all are covered.
Looking for UV-C disinfection solutions?
We offer a range of UV-C lamps and system for disinfection or air and surfaces. Contact us to discuss your particular requirements or arrange an online or onsite consultation.
UV-C dose requirements for common pathogens
Please note the figures below are provided as a guide, taken from independent research conducted over many years in a range of settings. We recommend that where specific reductions and results are required, testing is carried out to prove and validate the effects of various exposure levels and doses.
| Microbe | Type | D90 | Media | Source |
|---|---|---|---|---|
| Salmonella enteritidis | Veg | 10 J/m2 | Surface | Collins 1971 |
| E. coli | Veg | 55 J/m2 | Surface | Hollaender 1955 |
| Staphylococcus aureus | Veg | 66 J/m2 | Surface | Gates 1934 |
| Listeria monocytogenes | Veg | 156 J/m2 | Surface | Kim 2002 |
UV-C dose required to inactivate SARS CoV-2 (coronavirus)
At the start of the SARS CoV-2 pandemic, Dr. Anthony Griffiths, Associate Professor of Microbiology at Boston University School of Medicine and his team treated inoculated material with different doses of UV-C radiation coming from a UV-C light source and assessed the inactivation capacity under various conditions. The team applied a dose of 50 J/m2, resulting in a reduction of the SARS-CoV-2 virus of 99%. Based on the data, it was determined that a dose of 220 J/m2 will result in a reduction of 99.9999%.
UV-C dose required to inactivate bacteria
| Microbe | Type | D90 | Media | Source |
|---|---|---|---|---|
| Acinetobacter baumannii | Veg | 18 J/m2 | Surface | Rastogi 2007 |
| B. atrophaeus (B. globigii) | Sp | 144 J/m2 | Air | EPA 2006 |
| Bacillius anthracis spores | Sp | 743 J/m2 | Surface | Knudson 1986 |
| Bacillus cereus spores | Sp | 408 J/m2 | Surface | Benoit 1990 |
| Bacillus megatherium | Sp | 273 J/m2 | Surface | Hercik 1937 |
| Bacillus subtilis | Veg | 14 J/m2 | Air | Nakamura 1987 |
| Bacillus subtilis spores | Sp | 149 J/m2 | Air | Ke 2009 |
| Burkholderia cepacia | Veg | 22 J/m2 | Air | Fletcher 2004 |
| Corynebacterium diphtheriae | Veg | 33 J/m2 | Surface | Sharp 1939 |
| Escherichia coli | Veg | 55 J/m2 | Surface | Hollaender 1955 |
| Escherichia coli | Veg | 11 J/m2 | Air | Koller 1939 |
| Francisella tularensis | Veg | 288 J/m2 | Air | Beebe 1959 |
| Haemophilus influenzae | Veg | 38 J/m2 | Surface | Mongold 1992 |
| Halobacterium sp. NRC-1 | Veg | 25 J/m2 | Surface | Crowley 2006 |
| Legionella dumoffi | Veg | 24 J/m2 | Surface | Knudson 1985 |
| Legionella bozemanii | Veg | 15 J/m2 | Surface | Knudson 1985 |
| Legionella gormani | Veg | 26 J/m2 | Surface | Knudson 1985 |
| Legionella jordanis | Veg | 11 J/m2 | Surface | Knudson 1985 |
| Legionella longbeach | Veg | 11 J/m2 | Surface | Knudson 1985 |
| Legionella micdadei | Veg | 15 J/m2 | Surface | Knudson 1985 |
| Legionella oakridgensis | Veg | 22 J/m2 | Surface | Knudson 1985 |
| Legionella pneumophila | Veg | 5 J/m2 | Surface | Knudson 1985 |
| Legionella wadsworthii | Veg | 4 J/m2 | Surface | Knudson 1985 |
| Listeria monocytogenes | Veg | 156 J/m2 | Surface | Kim 2002 |
| Micrococcus candidus | Veg | 61 J/m2 | Surface | Hollaender 19855 |
| Micrococcus piltonesis | Veg | 81 J/m2 | Surface | Rentschler 1941 |
| Micrococcus sphaeroides | Veg | 100 J/m2 | Surface | Rentschler 1941 |
| Mycobacterium bovis BCG | Veg | 22 J/m2 | Surface | Collins 1971 |
| Mycobacterium bovis BCG | Veg | 33 J/m2 | Air | Ko 2000 |
| Mycobacterium parafortuitum | Veg | 46 J/m2 | Air | Peccia 2001 |
| Mycobacterium phlei | Veg | 63 J/m2 | Air | Riley 1976 |
| Mycobacterium smegmatis | Veg | 12 J/m2 | Air | Gillis 1974 |
| Mycobacterium tuberculosis | Veg | 11 J/m2 | Surface | Collins 1971 |
| Mycobacterium tuberculosis | Veg | 5 J/m2 | Air | Riley 1976 |
| Mycoplasma arthritidis | Veg | 7 J/m2 | Surface | Furness 1977 |
| Mycoplasma fermentans | Veg | 9 J/m2 | Surface | Furness 1977 |
| Mycoplasma hominis | Veg | 7 J/m2 | Surface | Furness 1977 |
| Mycoplasma Orale type 1 | Veg | 11 J/m2 | Surface | Furness 1977 |
| Mycoplasma Orale type 2 | Veg | 6 J/m2 | Surface | Furness 1977 |
| Mycoplasma pheumoniae | Veg | 8 J/m2 | Surface | Furness 1977 |
| Mycoplasma salivarium | Veg | 11 J/m2 | Surface | Furness 1977 |
| Neisseria catarrhalis | Veg | 44 J/m2 | Surface | Rentschler 1941 |
| Nocardia asteroides | Veg | 280 J/m2 | Surface | Chick 1963 |
| Phytomonas tumefaciens | Veg | 44 J/m2 | Surface | Rentschler 1941 |
| Proteus vulgaris | Veg | 30 J/m2 | Surface | Rentschler 1941 |
| Pseudomonas aeruginosa | Veg | 55 J/m2 | Surface | Hollaender 1955 |
| Pseudomonas aeruginosa | Veg | 4 J/m2 | Air | Sharp 1940 |
| Pseudomonas fluorescens | Veg | 35 J/m2 | Surface | Rentschler 1941 |
| Pseudomonas fluorescens | Veg | 3 J/m2 | Air | van Osdell 2002 |
| Salmonella enteritidis | Veg | 10 J/m2 | Surface | Collins 1971 |
| Salmonella typhi | Veg | 21 J/m2 | Surface | Sharp 1939 |
| Sarcina lutea | Veg | 197 J/m2 | Surface | Rentschler 1941 |
| Serratia indica | Veg | 209 J/m2 | Air | Harstad 1954 |
| Serratia marcescens | Veg | 22 J/m2 | Surface | Sharp 1939 |
| Serratia marcescens | Veg | 115 J/m2 | Air | Ko 2000 |
| Shigella paradysenteriae | Veg | 17 J/m2 | Surface | Sharp 1939 |
| Spirillum rubrum | Veg | 44 J/m2 | Surface | Rentschler 1941 |
| Staphylococcus albus | Veg | 33 J/m2 | Surface | Rentschler 1941 |
| Staphylococcus albus (1) | Veg | 23 J/m2 | Air | Rentschler 1942 |
| Staphylococcus albus (2) | Veg | 52 J/m2 | Air | Rentschler 1942 |
| Staphylococcus aureus | Veg | 66 J/m2 | Surface | Gates 1934 |
| Staphylococcus aureus | Veg | 20 J/m2 | Air | Nakamura 1987 |
| Staphylococcus epidermis | Veg | 29 J/m2 | Air | van Osdell 2002 |
| Streptococcus agalactiae | Veg | 5 J/m2 | Air | Luckiesh 1949 |
| Streptococcus haemolyticus | Veg | 22 J/m2 | Surface | Sharp 1939 |
| Streptococcus pneumoniae | Veg | 468 J/m2 | Surface | Gritz 1990 |
| Streptococcus pyogenes | Veg | 4 J/m2 | Surface | Lidwell 1950 |
| Streptococcus pyogenes | Veg | 1 J/m2 | Air | Luckiesh 1949 |
| Stroptococcus viridans | Veg | 20 J/m2 | Surface | Sharp 1939 |
UV-C dose required to inactivate viruses
| Microbe | Type | D90 | Media | Source |
|---|---|---|---|---|
| Adenovirus | dsDNA | 59 J/m2 | Air | Walker 2007 |
| Adenovirus type 2 | dsDNA | 400 J/m2 | Surface | Day 1974 |
| Adenovirus type 40 | dsDNA | 300 J/m2 | Surface | Meng 1996 |
| Adenovirus type 41 | dsDNA | 240 J/m2 | Surface | Meng 1996 |
| Bacteriophage MS2 | dsRNA | 61 J/m2 | Air | Walker 2007 |
| Bacteriophage MS2 | dsRNA | 4 J/m2 | Air | Tseng 2005 |
| Coliphage X-174 | dsDNA | 4 J/m2 | Air | Tseng 2005 |
| Coliphage PRD1 | dsDNA | 87 J/m2 | Surface | Meng 1996 |
| Coliphage T7 | dsDNA | 10 J/m2 | Air | Tseng 2005 |
| Coronavirus | ssRNA | 3 J/m2 | Air | Walker 2007 |
| Coxsackievirus | ssRNA | 21 J/m2 | Air | Jensen 1964 |
| Human Cytomegalovirus | dsDNA | 658 J/m2 | Surface | Albrecht 1974 |
| Influenza A virus | ssRNA | 19 J/m2 | Air | Jensen 1964 |
| Newcastle Disease Virus | ssRNA | 16 J/m2 | Surface | Rubin 1959 |
| phage phi 6 | dsRNA | 7 J/m2 | Air | Tseng 2005 |
| Poliovirus | dsRNA | 44 J/m2 | Surface | Ma 1994 |
| Poloiovirus type 1 | dsRNA | 41 J/m2 | Surface | Meng 1996 |
| Rauscher Murine Leukemia v. | ssRNA | 959 J/m2 | Surface | Stull 1976 |
| Rous Sarcoma virus (RSV) | ssRNA | 200 J/m2 | Surface | Rubin 1959 |
| Sindbis virus | ssRNA | 62 J/m2 | Air | Jensen 1964 |
| S. aureus phage | ssDNA | 82 J/m2 | Surface | Gates 1934 |
| Vaccina virus | ssDNA | 15 J/m2 | Air | Jensen 1964 |