WEBVTT 00:01.966 --> 00:04.433 align:left position:10% line:77% size:80% UDY WOODRUFF: As we have been mentioning, the U.S. has passed yet another tragic marker 00:04.433 --> 00:06.933 align:left position:30% line:89% size:60% in the pandemic. 00:06.933 --> 00:11.000 align:left position:10% line:71% size:80% More than 200,000 people have died in this country from COVID-19 and related complications. 00:13.000 --> 00:16.966 align:left position:10% line:77% size:80% That, in a period of less than eight months, is nearly twice as many Americans who have 00:18.500 --> 00:22.600 align:left position:20% line:77% size:70% been killed in every major conflict since the Korean War combined. 00:24.466 --> 00:28.166 align:left position:10% line:77% size:80% Our understanding of how the coronavirus is spreading continues to evolve. We want to 00:30.000 --> 00:32.333 align:left position:10% line:77% size:80% use this moment to clarify much of the latest scientific thinking. 00:32.333 --> 00:37.366 align:left position:10% line:77% size:80% First, a report from Stephanie Sy, followed by a conversation with William Brangham. 00:37.366 --> 00:42.333 align:left position:10% line:77% size:80% WOMAN: The coronavirus can remain infectious on plastic and steel surfaces for up to three 00:43.000 --> 00:45.033 align:left position:40% line:89% size:50% days. 00:45.033 --> 00:47.066 align:left position:10% line:77% size:80% WOMAN: That has many people worried about shopping and other everyday tasks. 00:47.066 --> 00:50.533 align:left position:10% line:77% size:80% MAN: Because you have got to be putting that disinfectant on these groceries. 00:50.533 --> 00:55.400 align:left position:10% line:77% size:80% STEPHANIE SY: This was the sound of fear early in the pandemic, after studies showed that 00:55.400 --> 01:00.300 align:left position:20% line:77% size:70% the novel coronavirus could live on surfaces for hours, even days. 01:00.300 --> 01:05.200 align:left position:10% line:71% size:80% It led to a furious wave of scrubbing, disinfecting and sold-out cleaning supplies across the 01:05.866 --> 01:07.933 align:left position:40% line:89% size:50% country. 01:07.933 --> 01:09.933 align:left position:10% line:77% size:80% DR. EMANUEL GOLDMAN, Rutgers New Jersey Medical School: But the problem with those experiments 01:09.933 --> 01:12.366 align:left position:10% line:77% size:80% is that they didn't relate to what a real-life scenario would be like. 01:12.366 --> 01:17.366 align:left position:10% line:77% size:80% STEPHANIE SY: That's Dr. Emanuel Goldman, a microbiologist at Rutgers New Jersey Medical 01:17.900 --> 01:19.933 align:left position:40% line:89% size:50% School. 01:19.933 --> 01:23.233 align:left position:10% line:77% size:80% In July, he published this article in the British medical journal "The Lancet" arguing 01:23.233 --> 01:28.066 align:left position:10% line:77% size:80% that these early studies greatly exaggerated the amount of virus that could actually be 01:28.066 --> 01:33.066 align:left position:10% line:71% size:80% found on surfaces in the real world. He pointed out that the lowest amount of infectious particles 01:34.700 --> 01:39.233 align:left position:20% line:77% size:70% researchers used to test surfaces in the lab was 10,000, a huge amount. 01:41.300 --> 01:43.633 align:left position:10% line:77% size:80% DR. EMANUEL GOLDMAN: You would need something like 100 people coughing or sneezing on the 01:43.633 --> 01:48.600 align:left position:10% line:77% size:80% same small surface area to get anywhere near the amount of virus that they used in these 01:49.266 --> 01:51.233 align:left position:30% line:89% size:60% experiments. 01:51.233 --> 01:54.866 align:left position:10% line:77% size:80% STEPHANIE SY: He says these mistakes, and a lack of scrutiny, have siphoned limited 01:54.866 --> 01:59.833 align:left position:10% line:77% size:80% resources from everything from subway systems to schools for excessive deep cleaning that 02:01.266 --> 02:03.233 align:left position:10% line:83% size:80% shows little evidence of helping prevent COVID spread. 02:03.233 --> 02:07.366 align:left position:10% line:77% size:80% DR. EMANUEL GOLDMAN: Our mothers taught us, you go to the bathroom, you wash your hands. 02:07.366 --> 02:11.033 align:left position:10% line:77% size:80% You prepare food, you wash your hands. You touch something dirty, you wash your hands. 02:11.033 --> 02:12.700 align:left position:10% line:89% size:80% That's all you have to do. 02:12.700 --> 02:17.500 align:left position:20% line:77% size:70% Normal, routine hygiene is sufficient to protect against this virus. 02:19.400 --> 02:22.133 align:left position:10% line:77% size:80% STEPHANIE SY: Meanwhile, he adds, not enough money and attention have been paid to what 02:22.133 --> 02:26.066 align:left position:10% line:83% size:80% we now know is the primary way the virus travels: the air. 02:26.066 --> 02:30.433 align:left position:10% line:77% size:80% DR. EMANUEL GOLDMAN: A teacher from a school system saying they were going to shut down 02:30.433 --> 02:35.433 align:left position:10% line:77% size:80% the schools one day a week for deep cleaning and disinfection. Wouldn't it be better to 02:37.466 --> 02:41.433 align:left position:10% line:77% size:80% use it instead on ventilation systems or hiring more teachers, so you could have fewer students 02:42.033 --> 02:44.033 align:left position:30% line:89% size:60% per class? 02:44.033 --> 02:44.966 align:left position:10% line:77% size:80% DR. SHELLY MILLER, University of Colorado Boulder: You want to try to replicate the 02:44.966 --> 02:47.600 align:left position:10% line:89% size:80% outside, indoors, in your space. 02:47.600 --> 02:51.700 align:left position:10% line:71% size:80% STEPHANIE SY: Dr. Shelly Miller is an environmental engineer at the University of Colorado Boulder. 02:54.200 --> 02:56.800 align:left position:10% line:71% size:80% For decades, she's studied the way pollutants and infectious diseases spread in indoor spaces, 02:58.800 --> 03:02.766 align:left position:10% line:77% size:80% and over the summer helped her own university prepare for when students and faculty return 03:02.766 --> 03:05.266 align:left position:30% line:89% size:60% to campus. 03:05.266 --> 03:08.133 align:left position:10% line:71% size:80% DR. SHELLY MILLER: You want to control the source of the contaminants. And, in this pandemic, 03:08.133 --> 03:13.133 align:left position:10% line:71% size:80% the sources are the infectious people inside. And so, to control the release of virus, you 03:16.333 --> 03:21.333 align:left position:10% line:77% size:80% want to wear a mask, and you also want to be outside of their personal cloud. 03:23.400 --> 03:26.533 align:left position:20% line:71% size:70% But some of the virus can potentially leak into the environment, and then you have to 03:28.533 --> 03:30.600 align:left position:10% line:77% size:80% clean the environment. And the way to do that is the filtration and ventilation. 03:30.600 --> 03:35.500 align:left position:10% line:77% size:80% STEPHANIE SY: The simplest way to do that, she says, open a door or window. 03:37.400 --> 03:40.200 align:left position:10% line:77% size:80% But in many parts of the country where it's still too hot, or becoming too cold, to do 03:40.200 --> 03:45.200 align:left position:20% line:71% size:70% that, Miller says there are different ways to increase a building's mechanical ventilation 03:45.800 --> 03:47.766 align:left position:30% line:89% size:60% and filtration. 03:47.766 --> 03:51.766 align:left position:10% line:77% size:80% Here's a basic guide: Buildings up to code should already be replacing the inside air 03:53.733 --> 03:56.800 align:left position:10% line:77% size:80% with outside air three times an hour. But with coronavirus, that should be doubled, 03:58.400 --> 04:02.500 align:left position:20% line:77% size:70% to six exchanges per hour, and, ideally, to nine exchanges per hour. 04:02.500 --> 04:07.500 align:left position:10% line:77% size:80% And, crucially, the more people there are contained in a space, the more exchanges are 04:10.066 --> 04:12.700 align:left position:10% line:71% size:80% needed. HEPA filters, which stands for high-efficiency particulate air, should also be added to ventilation 04:14.566 --> 04:16.800 align:left position:10% line:89% size:80% systems to increase protection. 04:16.800 --> 04:21.800 align:left position:10% line:77% size:80% If I walk into a restaurant or a classroom, is there a way for me to personally tell if 04:25.166 --> 04:27.900 align:left position:10% line:83% size:80% that is a safe place to be, if there's enough ventilation? 04:27.900 --> 04:32.466 align:left position:20% line:71% size:70% DR. SHELLY MILLER: Unfortunately, at this point in time, no. And that is why, a lot 04:32.466 --> 04:37.000 align:left position:10% line:77% size:80% of times, I have been saying, well, we really need to address this. We need to give buildings 04:37.000 --> 04:42.000 align:left position:20% line:71% size:70% and classrooms and other facilities resources, so they can -- so they can let the public 04:43.200 --> 04:45.666 align:left position:20% line:83% size:70% know how they have attended to this. 04:45.666 --> 04:49.766 align:left position:10% line:77% size:80% STEPHANIE SY: She and others say the Centers for Disease Control and Prevention and the 04:49.766 --> 04:54.766 align:left position:10% line:77% size:80% World Health Organization have been too slow to move away from early guidance on surface 04:56.633 --> 05:00.166 align:left position:10% line:77% size:80% disinfection, and towards clearer guidance on preventing airborne transmission. 05:02.266 --> 05:05.666 align:left position:20% line:71% size:70% Last Friday, the CDC did add language on its Web site about aerosols from coughing or breathing 05:07.700 --> 05:11.033 align:left position:10% line:77% size:80% spreading the virus, and the need for ventilation, then suddenly removed it. 05:11.033 --> 05:14.900 align:left position:10% line:77% size:80% DR. SHELLY MILLER: So, the only rule of thumb I can say is, if you walk into a space and 05:14.900 --> 05:19.900 align:left position:10% line:77% size:80% it feels hot and stuffy in there, and you can smell smoke and you can smell different 05:22.333 --> 05:25.833 align:left position:10% line:71% size:80% odors, then it's probably not ventilated enough, and you probably shouldn't spend very much 05:26.433 --> 05:28.533 align:left position:30% line:89% size:60% time in there. 05:28.533 --> 05:31.333 align:left position:10% line:77% size:80% STEPHANIE SY: Even portable air cleaners can help, and Dr. Miller and her colleagues have 05:31.333 --> 05:35.933 align:left position:10% line:77% size:80% created a guide for schools on these, which you can find on our Web site. 05:35.933 --> 05:40.200 align:left position:10% line:77% size:80% The bottom line: If you're thinking about going back to the gym, to a restaurant, your 05:40.200 --> 05:45.200 align:left position:20% line:71% size:70% office or school, keep washing your hands, keep wearing your mask, and keep social distancing. 05:47.100 --> 05:51.300 align:left position:10% line:77% size:80% But don't let those deep cleans fool you. Ask what they have done about the air. 05:51.300 --> 05:55.233 align:left position:10% line:77% size:80% DR. EMANUEL GOLDMAN: The problem is that it's been out there for so long, and Shakespeare 05:55.233 --> 06:00.266 align:left position:10% line:77% size:80% said it the best, what's done cannot be undone. And it's going to be a long time to turn the 06:02.200 --> 06:06.400 align:left position:10% line:77% size:80% ship around, if ever, because a lot of people still are operating on these assumptions. 06:07.966 --> 06:09.900 align:left position:20% line:77% size:70% STEPHANIE SY: For the "PBS NewsHour," I'm Stephanie Sy in Phoenix.