The on-going pandemic has forced people to worry about hygiene and sanitisation. This has led them to look beyond the easily available over-the-counter alcohol-based sanitizers. Many have resorted to UV Lights to sanitize the essential goods they purchase from the market.

These UV Lights are made up of UV-C light – which has a wavelength between 200-270 nanometres, and a midrange between 250-253 nanometres which kills bacteria. On the UV light spectrum, there are different wavelengths of light such as UV-A, B and C lights. Only the UV-C light can kill germs. UV-C is convenient to use and no chemicals are needed. Therefore, you won’t leave any chemical residue behind. UV only works in its light path, so make sure that the object you want to sterilize, is kept directly in line with the UV light.

Since, we are dealing with UV light which is said to be harmful for human body, there are safety measures which need to be kept in mind. Some of them are mentioned below -

• Always use appropriate PPE when using UV Light: UV face shield, goggles, gloves, buttoned-up lab coat.
• Enclose the light generated by the lamp to the extent possible.
• Cover arms, neck and feet when using UV Light.
• Avoid touching or scratching the glass section of the lamp.
• Do not touch the lamp while working. Let the lamp cool at least 15 minutes before opening the lamp compartment door. The arc lamp envelope reaches high temperatures during normal operation and can cause severe burns if touched.
• When using UV Light, make sure to have proper ventilation that are not ozone free.
• Use a manual or electronic shutter to close the beam when the source is not in use.
• Do not use lamp near paper, cloth, or other combustible material.
• ALWAYS keep the lamp in the provided protective case or cover until installation.
• Save the protective case or cover and packaging materials (box) for lamps that have been used to their rated service life. Use the protective case when disposing of the lamps.
• Limit access to areas where UV sources are used and never look directly at the beam.
• Avoid overnight UVC lamps.
• It is safe to enter a room after 30mins after germicidal UV disinfection has been performed.
• Accidental look at the light from few feet distance is fine, but don't stare at it for long. Again, distance is an important factor.
• Long hours exposure of mild UV-C can reduce the life of items made of mica. Also, Dark coloured things may lose their colour and whiter things might become yellow.

The studies conducted by US National Institute for Occupational Safety and Health (NIOSH) shows that exposure to UV light should be controlled and limited when in use. The total intensity from 320 to 400 nm hitting an unprotected eye should not exceed 10 W m-2 for periods longer than 1000 seconds. For shorter exposure times, the energy density should not exceed 104 J m-2.

When buying, choose the UV device carefully after reading the instructions and understanding your need. Stay safe.