Can the Sun Help To Eliminate Bacteria?

Quck answer

The Sun’s ultraviolet (UV) rays can help kill germs and disinfect surfaces. UV radiation has been used for decades as a sanitizing method in hospitals and laboratories. It can effectively destroy bacteria, viruses, and other microorganisms by damaging their DNA and preventing them from reproducing. However, direct exposure to the Sun’s UV rays can also be harmful to humans, causing sunburn and increasing the risk of skin cancer. Therefore, it is important to use proper precautions such as sunscreen and protective clothing when using the Sun as a disinfecting method.


Oh…wonderful, wonderful sunlight! Throughout the freezing, snowy winter days and the damp, rainy spring days, we eagerly await the warm, sunny days of summer. There’s nothing quite like soaking up the warm beams of the Sun on a gorgeous summer day.

However, we are also aware that we must be cautious of the Sun’s rays. Excessive exposure to sunlight can result in a painful sunburn. If you’ve ever experienced a sunburn, you understand what we mean. That’s why it’s crucial to wear sunscreen when outdoors.

Nevertheless, lately, researchers have been uncovering potential benefits of the Sun’s rays that were previously unknown to us. Specifically, some researchers have been conducting experiments to explore the Sun’s ability to eliminate bacteria!

Adults frequently urge children to wash their hands to get rid of bacteria. Can you skip using soap and water and simply expose your hands to the Sun? Not exactly!

Scientists have discovered that a specific type of ultraviolet light emitted by the Sun can be highly effective in eliminating bacteria. How effective, you ask? How about eliminating over 99% of bacteria? That’s what we call effective!

In fact, manufacturers have designed special ultraviolet lamps for use in specific industries where it’s crucial to eliminate nearly all bacteria. These industries include sewage treatment plants and hospitals.

So why won’t exposing your hands to the Sun clean them? To eliminate bacteria, a very specific wavelength of ultraviolet light — 254 nanometers — is required. The Sun produces this particular type of ultraviolet light, but most of it is absorbed by the Earth’s atmosphere.

As a result, only a small amount of this ultraviolet light actually reaches the Earth’s surface. That’s why the aforementioned industries must use special ultraviolet lamps to generate it.

How does this special ultraviolet light eliminate bacteria? It does so by inducing mutations in the DNA of bacteria and viruses. Although these bacteria may not be eliminated immediately, the special ultraviolet light weakens them and prevents them from reproducing or surviving for long periods.

Unfortunately, ultraviolet light can only eliminate the bacteria it directly contacts. If bacteria find hiding spots, such as shaded crevices, they can remain safe from the Sun’s ultraviolet rays.

Scientists have also started using ultraviolet radiation to help reduce the spread of water-borne diseases in developing countries. In many parts of the world, access to safe drinking water can be challenging. The invention of solar water decontamination techniques has aided in providing clean drinking water to numerous individuals.

With these techniques, people fill plastic bottles with water and leave them in direct sunlight for at least six hours. The Sun’s ultraviolet radiation and increased water temperatures work together to eliminate harmful bacteria in the water. Of course, these techniques require strong sunlight and small amounts of water. However, they have proven to be quite effective in reducing water-borne diseases so far.

Give It a Try

We hope today’s Wonder of the Day brightened your day! Light up a friend’s or family member’s life by exploring the following activities with them:

  • Aside from its germ-killing abilities, what do you like about sunlight? Create a drawing that represents your thoughts and feelings about sunlight. Be imaginative! Use your artwork to express how the Sun affects you. Enjoy and share your artwork with your friends and family. What do they enjoy about sunlight?
  • You have already read about the various uses of ultraviolet light, such as in sewage treatment plants and hospitals. Can you think of other places where ultraviolet lamps could be useful for sanitization and germ-killing? Make a list of at least five potential new markets for these lamps. Conduct some internet research to find out if any of the industries you thought of are already using ultraviolet lamps for germ-killing. Have fun thinking like a scientist and a business owner. Perhaps one day you can pioneer new applications for these products!
  • If you’re up for a challenge, visit the UV Radiation page of the United States Environmental Protection Agency to learn more about ultraviolet radiation. Share your newfound knowledge with a friend or family member. You never know when what you learn might help someone become more aware of the dangers of UV ray exposure!

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