Plastic and other surfaces (Part 1)

Posted by watchmen
September 21, 2020
Posted in OPINION

The virus that causes the coronavirus disease 2019 (COVID-19)  survives outside the human body in the air, on objects and surfaces.

A study published in March in The New England Journal of Medicine shows that the virus is stable for several hours to days in aerosols and on surfaces.

The study was conducted by scientists at the U.S. National Institutes of Health (NIH), U.S. Centers for Disease Control and Prevention (CDC), University of California Los Angeles and Princeton University.

The scientists found that the Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2), the virus that causes COVID-19, was detectable in aerosols for up to three hours, up to four hours on copper, up to 24 hours on cardboard and up to two to three days on plastic and stainless steel.

The study mimicked the virus coming from an infected person through coughing or touching surfaces in a household or hospital setting. (According to, a single cough can produce up to 3,000 droplets that may contain the virus.)

The study suggests that people may acquire the virus through the air and after touching contaminated objects.

It found that the time it takes for half of the amount (called the half-life) of the virus to be viable is 1.1 to 1.2 hours on copper, 5.6 hours on stainless steel and 6.8 hours on plastic. While copper tends to kill the virus, the virus lasts that long on stainless steel that are used on many ordinary things like door handles and on the surface of plastic or on objects coated with the material.

The study found that the virus could survive in droplets for up to three hours after being coughed out into the air. Fine droplets between 1-5 micrometers in size (that’s 30 times smaller than a human hair) remain suspended for several hours in still air, reports.

Another study, published as a research letter in The Lancet Microbe medical journal, detected the virus for up to 30 minutes on paper; up to 30 minutes on tissue paper; a day on wood and cloth; up to two days on glass and paper money; and up to four days on stainless steel, the inner layer of a face mask and plastic.

The virus remained on the outer layer of a mask for up to seven days, according to another study, this time conducted by researchers at the School of Public Health, The University of Hong Kong.

Take note, according to a article, the numbers are “only approximations and not exact time limits.”

One more study released in May by microbiologists in Beijing, China, found that Sars-CoV-2 could survive and remain infectious on smooth surfaces including plastic, stainless steel, glass, ceramics and latex gloves for up to seven days, reports.


Dr. Joseph D. Lim is the former Associate Dean of the UE College of Dentistry, former Dean of the College of Dentistry, National University, past president and honorary fellow of the Asian Oral Implant Academy, and honorary fellow of the Japan College of Oral Implantologists. Honorary Life Member of Thai Association of Dental Implantology. For questions on dental health, e-mail or text 0917-859151./WDJ


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