How Far Can Coronavirus Droplets Travel?
BALDWIN: Welcome back on this Monday afternoon. I'm Brooke Baldwin. As we're learning of new dire projections of an increase in deaths and cases, at least 40 states will have started reopening businesses in some way by the end of this week, and among them the state of Florida, where phase one begins today. CNN's Randi Kaye is live there in West Palm Beach. And, Randi, a million people, a million have filed for unemployment thus far in Florida. So the governor is feeling the pressure to get stores and services open. But it is still with social distancing, right?</s>RANDI KAYE, CNN CORRESPONDENT: Supposedly. People are certainly being asked to social distance, Brooke, but already we're seeing problems. In fact, in Miami Beach, they have already closed a park and they have issued 8,000, 8,000 violations for not social distancing and not wearing the face masks, as is required there. But, as you mentioned, this is phase one. It's a learning experience, apparently. More beaches are opening today, including popular ones in Clearwater and Destin and Pensacola. Restaurants are opening. State parks are opening. Restaurants have limited capacity. Also, retailers are opening to about 25 percent capacity. Some things are still closed, like some of the museums are closed here. Of course, the movie theaters are closed, the salons and the spas, and also three major counties here in South Florida, including this one where I am, Palm Beach County, as well as Broward County and Miami-Dade. And that's because those were the hardest-hit counties. That's also about 30 percent of the state's population, so a very highly populated area, about 6.2 million people living there. But, as you mentioned, Brooke, social distancing, it is key, which is why we wanted to know, how far does a cough really travel? So we went to a Florida lab to find out.</s>UNIDENTIFIED MALE: Have you cough. Three, two, one.</s>KAYE (voice-over): Inside this lab at Florida Atlantic University, two engineering professors are measuring the power of a cough.</s>UNIDENTIFIED MALE: Two, one.</s>KAYE: Using a dummy, they fill its mouth with a mix of glycerin and water, then with a pump force the dummy to cough, then wait to see how far the droplets travel. They fill the air, visible with the green laser light, simulating what happens when we cough.</s>SID VERMA, FLORIDA ATLANTIC UNIVERSITY: It generates particles on the order of 10 to 20 microns, which is roughly close to what the smallest droplet sizes are when we cough.</s>KAYE: Take note how quickly the simulated respiratory droplets spread. The droplets expelled traveled a distance of three feet almost immediately. Within five seconds, the droplets were at six feet, then nine feet in just about ten seconds. Remember, nine feet is three feet beyond the recommended social distancing guidelines.</s>VERMA: Already reaching roughly nine feet now. It's still moving further, slowly.</s>KAYE: The fog of droplets lingered in the air, but kept moving forward, taking just another 30 to 40 seconds to float another three feet.</s>VERMA: It's getting closer to 12 feet now.</s>KAYE: Yes, he said 12 feet. Over and over again, the simulated droplets blew past the six-foot mark, often doubling that distance.</s>VERMA: OK. It has passed three feet already, approaching six feet. And it looks like it has crossed six feet. And now it has slowed down.</s>KAYE (on camera): How long might they linger at nine feet and 12 feet?</s>MANHAR DHANAK, CHAIRMAN, FAU ENGINEERING DEPARTMENT: So, at nine feet, they could linger for two to three minutes, OK? But the concentration is less than what it would be at, say, six feet by a factor of eight.</s>KAYE (voice-over): The professors say the droplets become less dense the further they travel, but they still hang in the air, still with the ability to carry disease. And watch this. Even when we put a simple mask on the dummy, particles still disperse from the sides of the mask, though they didn't travel far. (on camera): Certainly, if you are not wearing a mask, you are supposed to cough into your elbow. But if you cough into your hand, this is what happens. Let's turn out the lights. I will put my hand up against the mouth of this dummy and simulate a cough. You can see the droplets spray in all directions. They may not travel as far, maybe about three feet or so, but they spray everywhere. And they can linger in the air, possibly for as long as three minutes. (voice-over): Intensity of the cough matters. So we tested a gentle cough too. The lighter cough didn't go very far at all, about three feet. But the question remains, how close is too close? (on camera): Do you think, based on what you've seen in your own lab, that six feet is enough for social distancing?</s>DHANAK: Six feet is the minimum distance that you should keep. It seems that ...</s>KAYE: But further is better?</s>DHANAK: Further is better.</s>BALDWIN: Wow.</s>KAYE: So, we shot that inside, Brooke, in a small lab, but outside would be a very different story. Even with a slight breeze, how I'm feeling today, the professor said that the cough would go up and the droplets would disperse to the side, maybe it would travel about three or four feet. But what really got me was how long it hangs in the air. They said several minutes, as you heard there. So if you walk into an elevator or maybe a restaurant, now that they're starting to open, and somebody coughed just a few minutes before that, and you don't know it, those droplets are still in the air, and they can get you.</s>BALDWIN: No, that was incredible to see that demonstration. I just had no -- no idea how far a cough could potentially travel.</s>KAYE: No.</s>BALDWIN: Randi Kaye, thank you so much for doing that, just to show us. Appreciate it.</s>KAYE: Great to see you.</s>BALDWIN: Thank you very much. One drugmaker says it now has an antibody test that is nearly 100 percent effective. So, we will talk to an emergency room doctor and ask if that could be a game-changer. Plus, he will share the most promising treatments he has seen thus far more coronavirus patients in the ICU. So, stand by.