In recent years, research has delved into the benefits and applications of ultraviolet light in disinfection and sterilization. Its ability to penetrate microbial cells and cause cellular damage has been discovered to be a valuable tool for water disinfection and other purposes. Thus, multidisciplinary advancements in understanding the technologies that enable the generation of ultraviolet light have driven the development and optimization of disinfection and sterilization applications, resulting in a significant direct impact on food and health safety, as well as the well-being of individuals, among others.

UV Light and Its Disinfection Power

Ultraviolet light (UV) is a form of electromagnetic energy belonging to the non-visible light spectrum, with wavelengths ranging from 100 to 400 nanometers (nm). Within this broad spectrum, three main regions are distinguished based on wavelength: UVA, UVB, and UVC.

Types of UV Light

1. UVA (320-400 nm): With the highest wavelength, it can penetrate materials more easily. It constitutes 95% of solar UV radiation and can penetrate clouds or glass windows, making it dangerous for the skin by penetrating the skin layers, causing wrinkles, aging, and even skin cancer.

2.  UVB (280-320 nm): Represents the remaining 5% of solar UV radiation and is mostly absorbed by the atmosphere. Nonetheless, it can cause allergic reactions and skin cancer.

3. UVC (200-280 nm): Completely absorbed by the atmosphere, its presence is artificial. Although it does not pose a significant risk for skin cancer, it is highly effective against viruses and bacteria, being widely used in disinfection and sterilization applications.

Applications of UV Light

The initial discovery of UV light is associated with the German physicist and physiologist Johann Ritter in 1881, presenting its applications in living organisms as well as other uses. However, it was not until the late 19th century when Niels Finsen demonstrated the germicidal effects of UV light, which propelled its application in treating diseases such as tuberculosis and its subsequent adoption as a method for disinfection.

UV disinfection occurs by deactivating pathogens when interacting with nucleic acids, altering their genetic structure and preventing replication. DNA damage, especially associated with the formation of a sufficient number of thymine dimers that prevent replication, results in microbial inactivation. Despite its effectiveness, it is important to consider that some microorganisms may have reactivation mechanisms, emphasizing the need for post-UV disinfection treatment precautions.

UV lamps, commonly mercury vapor lamps, emit light at germicidal wavelengths, primarily at 254 nm. Variants such as low-pressure and medium-pressure lamps offer different advantages in efficiency and operational range. Significant advances are currently being made in their commercial application with LEDs emitting these wavelengths. You can explore Pyroistech’s range of UV LED sources for disinfection applications in different ranges at the following link.

Regarding the use of UV light in disinfection applications, two main fields of application can be distinguished:

1. Air disinfection, especially in hospital environments.

2. Water treatment.

The advantage of UV disinfection systems is their effectiveness, as they can eliminate up to 99% of microorganisms without the need for chemicals or other methods. However, the generation of ozone (O3) produced by the photolysis of oxygen molecules when using these types of sources is a potential health concern, so they must be used in a controlled manner, in environments without personnel and well-ventilated. In the particular case of water treatment, the effectiveness of UV disinfection processes may be affected by water quality parameters such as turbidity and organic content, requiring pretreatment measures such as filtration and optimization of UV power delivery to ensure disinfection processes.

In summary, ultraviolet disinfection emerges as a reliable method to ensure microbiological safety in high-risk or contagion areas, such as hospitals, schools, and public transportation, as well as for water supplies or food environments. Thus, the advancement of technologies associated with UV light generation provides high versatility, allowing its application in different environments, from large-scale treatment plants to point-of-use systems at the user level, offering protection against a wide range of pathogens, allowing UV light-based disinfection systems to stand as a fundamental pillar to meet increasingly restrictive regulations and safeguard public health worldwide.

References:

1. Arod.com.mx: « Los tipos de radiación ultravioleta y sus diferencias: UVA, UVB y UVC » (https://arod.com.mx/2021/05/06/los-tipos-de-radiacion-ultravioleta-y-sus-diferencias-uva-uvb-y-uvc/)
2. PubMed Central: « Ultraviolet Disinfection » (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7644456/)
3. Gray, N. F. (n.d.). Chapter Thirty-Four – Ultraviolet Disinfection. In N. F. Gray (Ed.), Advances in Water Purification Techniques (pp. 701-726). Elsevier. (https://doi.org/10.1016/B978-0-12-415846-7.00034-2)
4. ScienceDirect: « Ultraviolet (UV) Radiation Disinfection » (https://www.sciencedirect.com/science/article/pii/S1684118217302001)