Experiment Shows Sunlight and Humidity Kill Coronavirus the Fastest

by DailyHealthPost Editorial

Even if you follow politics on a surface level, you may have heard Donald Trump’s recent statements that injecting disinfectant or shining UV light inside the body might be a good idea. Needless to say, the U.S. President’s proposition sparked debate and criticisms and for good reasons – injecting disinfectant in human lungs or bloodstream is an absurdly bad idea that shouldn’t need to be commented on, and shining UV light inside our lungs is as pointless as it is impractical.

When it comes to flat, non-porous surfaces, however, UV light, disinfectants, and other methods may be effective against the coronavirus. Research on the matter is yet to be made public but scientists claim the Covid-19 virus dies quicker under sunlight and even high humidity.

William Bryan, the science and technology adviser to the Department of Homeland Security recently said, the impact of ultraviolet light on the pathogen on flat and non-porous surfaces has already been observed and tested by U.S. scientists.


“The virus dies quickest in the presence of direct sunlight,” Bryan said.

“Our most striking observation to date is the powerful effect that solar light appears to have on killing the virus – both surfaces and in the air,” he also added. “We’ve seen a similar effect with both temperature and humidity as well, where increasing the temperature and humidity or both is generally less favorable to the virus.”

The fact that UV light has an overall sterilizing effect on many biological organisms isn’t news, however. UV light is even used in water filtration systems as it sterilizes waterborne microorganisms and prevents them from replicating and infesting the water.

Yet, the Covid-19 virus has been shown to spread widely even in sunny and warm-weather countries such as Thailand, Malaysia, and Singapore, which is why UV light’s effectiveness against it needs to be tested more thoroughly. 

Dr. Margaret Harris from the World Health Organization has shared that “the evidence is not supporting [the sunlight] theory”. Simply relying on the sun or the warm summer months to fix the pandemic that has infected over 3 million people as of the end of April is not realistic.

“I’m sorry but we cannot hope that summer is going to have the effect that many people hope it will,” said Harris.


William Bryan also agrees that it’d be “irresponsible” to expect the summer months to do our job for us, however, he believes they can provide an “opportunity to get ahead” of the pandemic as the storng UV rays might help disinfect at least some outdoor surfaces.

As adamant as Bryan is about the scientists testing UV light for the U.S. government, the fact remains that the study isn’t open to the public yet

Bryan did share some insight during a press conference at the White House with some of the findings of the experiment carried out by the National Biodefense Analysis and Countermeasures Center in Maryland. According to their findings, the virus can stay active on non-porous surfaces such as stainless steel for up to 18 hours. Additionally, it retains its strength for longer in dark and low-humidity environments.

On the other hand, in sun-rich and high-humidity places, the potency of the virus halves in just 6 hours, about three times faster. According to Bryan, when virus-infected surfaces were treated directly with especially strong sunlight and humidity, the virus’s strength seemed to disappear in a matter of minutes.

The same observations have been made about the virus when it’s inside airborne water droplets such as after a cough or speech – if it was in dark and humid places, the virus remained much more potent for longer. But, according to Bryan, when exposed to sunlight, the virus lost half its strength in 90 seconds.

Another finding was that isopropyl alcohol was a more effective disinfectant than bleach. The research behind that finding is also still not open to the public, however, so more developments are to be expected.