distancing and COVID-19: A law of diminishing returns<img alt="" src="/news/PublishingImages/social%20distancing-iStock-1216693230.jpg?RenditionID=1" style="BORDER:0px solid;" /><div id="__publishingReusableFragmentIdSection"><a href="/ReusableContent/36_.000">a</a></div><p>The first case of the novel coronavirus, COVID-19, in the United States was in late January. By mid-March, "social distancing" had entered the public lexicon. People altered their routines and local jurisdictions suggested, urged or required changes meant to slow the disease's spread.</p><p>By the end of June, however, public health officials and news outlets were talking about a second wave. In July, many states were pausing or reversing their plans to reopen while, for the second time, hospital systems worried about running out of room.</p><p>What could we have done better?</p><p>In an "editor's pick" paper published today in the journal <a href="">Chaos</a> of the American Institute of Physics, Washington University in St. Louis researchers in the lab of <a href="/Profiles/Pages/Rajan-Chakrabarty.aspx">Rajan Chakrabarty</a>, associate professor in the Department of Energy, Environmental & Chemical Engineering at the McKelvey School of Engineering, modeled the interplay between the duration and intensity of social distancing. They found a law of diminishing returns, showing that longer periods of social distancing are not always more successful when it comes to slowing the spread and that any strategy that involves social distancing requires other steps be taken in tandem.</p><p>"Conventional wisdom was, the more intense and long-term the social distancing, the more you will curb the disease spread," Chakrabarty said.<br/></p><p>"But that is true if you have social distancing implemented with contact tracing, isolation and testing. Without those, you will give rise to a second wave."</p><p>Added Payton Beeler, a second-year doctoral student in Chakrabarty's lab, who also worked with Pai Liu, a postdoctoral fellow: "What we have found is that if social distancing is the only measure taken, it must be implemented extremely carefully in order for its benefits to be fully realized."</p><p>Their susceptible, exposed, infected and recovered (SEIR) dynamics model used data gathered by Johns Hopkins University between March 18 and March 29, a period marked by a rapid surge in COVID-19 cases and the onset of social distancing in most U.S. states. Calibrating their model using these datasets allowed the authors to analyze unbiased results that had not yet been affected by large-scale distancing in place.</p><p>Unique to this project was the use of age stratification; the model included details on how much people of different age groups interact and how that affects the spread of transmission.</p><p>No matter what strategy they looked at, one thing was clear, Chakrabarty said: "Had social distancing been implemented earlier, we probably would've done a better job."</p><p>"Bending the curve using social distancing alone is analogous to slowing down the front of a raging wildfire without extinguishing the glowing embers."<br/></p><p><img src="/news/PublishingImages/Pages/Social-distancing-and-COVID-19-A-law-of-diminishing-returns/ShortTermDistancing.jpg" alt="ShortTermDistancing.jpg" style="margin: 5px;"/><br/></p><p><sub>This log-linear graph plots social distancing duration vs. percent reduction in medical demands (Credit: Chakrabarty Lab)</sub><br/></p><p>Researchers found that, over the short-term, more distancing and less hospital demand go hand in hand — but only up to two weeks. After that, time spent distancing does not benefit hospital demand as much; society would have to increase social distancing time exponentially in order to see a linear decrease in hospital demand.</p><p>Thus the diminishing return: Society would see smaller and smaller benefits to hospital demand the longer it spent social distancing.</p><p>If social distancing "alone" is to be implemented longer than two weeks, a moderate shut down, say between 50% to 70%, could be more effective for the society than a stricter complete shut down in yielding the largest reduction in medical demands.</p><p>Another strategy for flattening the curve involves acting intermittently, alternating between strict social distancing and no distancing to alleviate the strain on hospitals — as well as some of the other strains on the economy and well-being imposed by longer-term distancing.</p><p>According to the model, the most efficient distancing- to no- distancing ratio is 5 to 1; one day of no distancing for every five days at home. Had society acted in this way, hospital burden could have been reduced by 80%, Chakrabarty said. Exceeding this ratio, the model showed a diminishing return.</p><p>Critically, the researchers note that social distancing policy as a whole-of-government approach could not be successful without the implementation of wide-spread testing, contact tracing and isolation of those found to be infected.</p><p>"And you have to do it aggressively," Chakrabarty said. "If you do not, what you're going to do, the moment you lift social distancing, is give rise to a second wave."</p><p>That's because the people who are leaving their homes after distancing themselves are, ostensibly, all susceptible to COVID-19.</p><p>"Bending the curve using social distancing alone is analogous to slowing down the front of a raging wildfire without extinguishing the glowing embers," said Chakrabarty, whose other line of research focuses on the impacts of wildfires on climate and health.</p><p>"They are waiting to start their own fires once the wind carries them away."</p><p>The model cannot inform strategies going forward because it used data collected in March, before any large-scale social distancing was implemented. But Chakrabarty said it may be able to inform our actions if we find ourselves in a similar situation in the future.</p><p>"Next time, we must act faster and be more aggressive when it comes to contact tracing and testing and isolation," Chakrabarty said. "Or else this work was for nothing."</p><p> <br/></p><SPAN ID="__publishingReusableFragment"></SPAN><p><br/></p><p><br/></p><div class="cstm-section" style="font-size: 16px;"><h3>Rajan Chakrabarty<br/></h3><div style="text-align: center;"> <strong><a href="/Profiles/Pages/Rajan-Chakrabarty.aspx?_ga=2.219429401.1899543784.1594589061-2004324074.1591594841"><img src="/profiles/PublishingImages/Chakrabarty_Rajan.jpg?RenditionID=3" alt="" style="margin: 5px;"/></a> <br/><a href="/Profiles/Pages/Rajan-Chakrabarty.aspx"><strong></strong></a></strong></div><div style="text-align: center;"><ul style="text-align: left;"><li>Associate Professor of Energy, Environmental & Chemical Engineering<br/></li><li>Research: <span style="text-align: justify;">quantifying the dynamics and properties of the various "agents" that undergo multiple interactions to give rise to emergent behavior in environmental systems.</span><span style="font-size: 1em;"></span><br/></li></ul><p> <a href="/Profiles/Pages/Rajan-Chakrabarty.aspx?_ga=2.219429401.1899543784.1594589061-2004324074.1591594841">View Bio</a><br/></p></div></div><p><br/></p><span><div class="cstm-section"><h3>Media Coverage<br/></h3><div> <strong></strong></div><div><div style="color: #343434; text-align: center;"><strong>The Economic Times: </strong><a href="" style="color: #9e0918; outline: 0px;">Physical distancing not the 'magic mantra' for hospitals, will help ease burden on doctors but only to a point</a><br/></div><div style="color: #343434; text-align: center;"><br/></div><div style="color: #343434; text-align: center;"><strong>Deccan Herald: </strong><a href="">Study says physical distancing may help ease burden on hospitals, but only to a point</a><br/></div></div></div></span><br/>Brandie Jefferson2020-07-15T05:00:00ZRajan Chakrabarty's research shows that if social distancing is the only measure taken, it must be implemented extremely carefully for its benefits to be fully realized.<p>​Research finds distancing helps ease the burden on hospitals — but only to a point<br/></p> Engineering launches seminar series on race, STEM education<p>​In light of national conversations surrounding systemic racism, the McKelvey School of Engineering at Washington University in St. Louis will host a virtual seminar series on topics related to race and science, technology, engineering and math (STEM) education.<br/></p><img alt="" src="/news/PublishingImages/Education_Engineering_Race.jpg?RenditionID=1" style="BORDER:0px solid;" /><p>The series, titled "Education, Engineering & Race," is organized by Princess Imoukhuede, associate professor of biomedical engineering; Joseph O'Sullivan, the Samuel C. Sachs Professor of Electrical Engineering; Lori Setton, the Lucy & Stanley Lopata Distinguished Professor of Biomedical Engineering and chair of the Department of Biomedical Engineering; and Jessica Wagenseil, associate professor of mechanical engineering & materials science.</p><p>"We have an opportunity to come together as a community to better understand practices and policies in STEM education and engineering that support systemic racism," Setton said. "These are very clear obstacles to achieving our greatest objectives to provide educational opportunity and advance research to improve the human condition."</p><p>The seminar series will kick off July 30, when Odis Johnson will present "#ShutDownSTEM: Connecting Race and Policing to STEM Inequities."</p><p>Johnson is a professor of sociology and education; director of the Institute in Critical Quantitative, Computational, and Mixed Methodologies (ICQCM); and associate director of the Center for the Study of Race, Ethnicity, and Equity in the College of Arts & Sciences at WashU.</p><p>Future speakers include:</p><ul><li>Ebony McGee, who will present "Black, Brown, Bruised: How Racialized STEM Education Stifles Innovation" on Aug. 13; and</li><li>Brian Jefferson, who will present "Digitize and Punish: Racial Criminalization in the Digital Age" on Aug. 27.</li></ul><p>McGee is an associate professor of Diversity and STEM Education and principal investigator for the Institute in Critical Quantitative, Computational and Mixed Methodologies at Vanderbilt University, and Jefferson is an associate professor of geography and geographic information science and the O'Connell Scholar at the College of Liberal Arts and Sciences at the University of Illinois at Urbana-Champaign.</p><p>All seminar events will be followed by 30-minute moderated breakout discussions.</p><p>Registration for this event is required and can be <a href="" target="_blank">completed online</a>.<br/></p><div><div class="cstm-section"><h2 style="text-align: left;">​Event Dates<br/></h2><p style="text-align: center;"> <img src="/news/PublishingImages/Odis%20Johnson%20seminar%20speaker.jpg?RenditionID=3" alt="" style="margin: 5px;"/> <br/> </p><p style="text-align: center;"> <a href="/Events/Pages/education-engineering-race-seminar-series-20200730.aspx">July 30</a><br/>Odis Johnson, PhD<br/>"#ShutDownSTEM: Connecting Race and Policing to STEM Inequities"</p><p style="text-align: center;"> <img src="/Events/PublishingImages/Pages/education-engineering-race-seminar-series-20200812/mcgee-ebony.jpg?RenditionID=3" alt="" style="margin: 5px;"/> <br/> </p><p style="text-align: center;"> <a href="/Events/Pages/education-engineering-race-seminar-series-20200813.aspx">Aug. 13</a><br/>Ebony McGee, PhD<br/>"Black, Brown, Bruised: How Racialized STEM Education Stifles Innovation"</p><p style="text-align: center;"> <img src="/news/PublishingImages/Pages/mckelvey-engineering-launches-seminar-series-on-race-stem-education/jefferson-brian.jpg?RenditionID=3" alt="" style="margin: 5px;"/> </p><p style="text-align: center;"> <a href="/Events/Pages/education-engineering--race-seminar-series-20200827.aspx">Aug. 27</a><br/>Brian Jefferson, PhD<br/>"Digitize and Punish: Racial Criminalization in the Digital Age"<br/></p></div></div>Danielle Lacey2020-07-14T05:00:00ZThe series will kick off July 30, with a discussion on the connection between race, policing and STEM inequities.$2-million-to-further-develop-flow-batteries.aspx1345Ramani wins $2 million to further develop flow batteries <img alt="" src="/Profiles/PublishingImages/Ramani_Vijay.jpg?RenditionID=2" style="BORDER:0px solid;" /><p>The Department of Energy's Advanced Research Projects Agency-Energy (ARPA-E) has awarded the lab of Vijay Ramani, the Roma B. & Raymond H. Wittcoff Distinguished University Professor in the Department of Energy, Environmental & Chemical Engineering, $2 million to further develop and de-risk its electrode-decoupled redox flow battery technology, and to position the team for scale-up and deployment after the course of the project.</p><p>Ramani's lab, at the McKelvey School of Engineering, pioneered this battery concept to be used for long-duration, grid-scale energy storage. The researchers developed membrane technologies and novel, patent-pending flow battery chemistries that promise to significantly reduce the levelized cost of grid-scale (think gigawatt-hours of energy stored) energy storage.  <br/></p><div><p>This is the second such award for Ramani's lab; <a href="/news/Pages/Positively-charged-Engineers-win-2-million-grant-to-design-better-batteries.aspx">the first was awarded in 2016</a>. </p><p> <br/></p><p> </p><br/></div><p><br/></p>2020-07-10T05:00:00ZVijay Ramani and his lab will further develop and de-risk its electrode-decoupled redox flow battery technology and position the team for scale-up and deployment. Expert: Researchers focused on understanding virus transmission by aerosols<img alt="" src="/news/PublishingImages/aerosols-iStock-1217660166.jpg?RenditionID=2" style="BORDER:0px solid;" /><p>​On Monday, more than 230 scientists from around the world declared “It’s time to address airborne transmission of COVID-19.”</p><p>In a <a href="">letter signed by Washington University in St. Louis faculty and published in the journal Clinical Infectious Diseases</a>, directed toward “Most public health organizations, including the World Health Organization,” the scientists urged that public health organizations need to make recommendations beyond hand washing and mask-wearing.</p><p>Public health guidelines must address every potentially important pathway to slow spread of the disease, the letter stated. This would include measures that account for airborne transmission, including increased ventilation, supplemental ventilation with airborne infection controls and avoidance of overcrowding.<br/></p><p><a href="/Profiles/Pages/Brent-Williams.aspx?_ga=2.42307622.261613464.1594043570-2004324074.1591594841">Brent Williams</a>, the Raymond R. Tucker Distinguished InCEES Career Development Associate Professor in the Department of Energy, Environmental and Chemical Engineering at the McKelvey School of Engineering, is one of the experts in aerosols who reviewed the letter before its publication and signed it.<br/></p><p>“In the research community, we are mostly focused on fully understanding the details of this issue so we can continue to provide the most accurate information to medical experts and policy makers to help them to make informed decisions,” Williams said.</p><p>“This letter came from a place where the research community thought there was a lag in policy keeping up with the rapid-paced science underway to characterize the transmission of this virus.”</p><p rtenodeid="12"><strong>You are not an epidemiologist or a medical doctor. How does your expertise figure in this situation?</strong></p><p>“My research focuses on determining the sources, transformation and fate of particles in both outdoor and indoor environments. We work to determine marker molecules that could be used to distinguish the exact source of particles, typically differentiating between natural particles that may come from trees and vegetation versus human-influenced particles that come from our daily activities such as power and heat generation, industry, transportation and even from the chemicals we use in our homes and our personal care products. My research group also has expertise in studying window-opening behavior in homes to determine the mixing processes that occur as you combine indoor and outdoor air, one topic of this open letter.”</p><p rtenodeid="11"><strong>Didn’t we already know that the virus spread through the air? Isn’t that why we are wearing masks? What is this letter saying beyond that?</strong></p><p>“The WHO and other public health organizations still place much of their current guidance on promoting hand washing, social distancing and droplet precautions within short distances (e.g., 6-foot perimeter). They view airborne transmission from smaller particles only as a possible route of exposure, and mostly only through aerosol-generating procedures performed in health-care settings. We do, however, know that droplets generated from regular speaking, coughing, sneezing, etc., will generate particles that rapidly shrink to smaller sizes that can be suspended in air for long time periods (on the scale of hours) and transferred over long distances (for example, throughout an entire home). There is increasing evidence that the virus can remain viable in these microdroplets. This problem is especially critical for indoor environments that may be crowded and have inadequate ventilation.”</p><p rtenodeid="8"><strong>How big is one of these microdroplets?</strong></p><p>“Microdroplet is not a well-defined term, but in general we are concerned with particles that are smaller than about 5 micrometers. For comparison, the width of a human hair is around 70 micrometers, so these are particles smaller than you would notice with the naked eye. Once they are smaller than 5 micrometers, they can remain suspended in the air for extended periods.”</p><p><strong>Why aren’</strong><strong></strong><strong>t the current recommended guidelines sufficient (wash your hands, wear a mask, stay 6 feet from others)?</strong></p><p>“Most masks are capable of preventing the spray of larger droplets leaving the mouth, so if every person in an environment is wearing a mask, there are limited droplets released and limited resulting evaporated microdroplets present. However, it only takes one person without a mask before microdroplets can be generated, and everyone else with a mask becomes at risk since most masks do not filter incoming microdroplets well, especially in the 0.1-1 micrometer size range. To reduce indoor particle concentrations, we typically use mechanical (HVAC) or natural (window-opening) ventilation procedures. However, clearing out these microdroplets from indoor environments can be challenging. HVAC filters have diminished filtration efficiency for particles in this small size range, and window-opening has its own limitations in extreme temperatures and has diminished effectiveness when the outdoor air is stagnant. Room air purifiers — HEPA filters for example — can help to lower the concentration of indoor microdroplets.”</p><p rtenodeid="14"><strong>What does your research tell you about best practices when it comes to the spread of this virus?</strong></p><p>“I would urge greater caution in indoor environments, keeping the occupancy levels at a minimum, wearing masks when in shared public settings and increasing ventilation and filtration of the indoor air.”<br/></p><div class="cstm-section" style="font-size: 16px;"><h3>Brent Williams<br/></h3><div style="text-align: center;"> <strong> <a href="/Profiles/Pages/Brent-Williams.aspx"> <img src="/Profiles/PublishingImages/Williams_Brent.jpg?RenditionID=3" alt="" style="margin: 5px;"/></a> <br/><a href="/Profiles/Pages/Brent-Williams.aspx"><strong></strong></a></strong></div><div style="text-align: center;"><ul style="text-align: left;"><li>Raymond R. Tucker Distinguished InCEES Career Development Associate Professor<br/></li><li>Expertise: Chemical properties of atmospheric and indoor gases and particles<span style="font-size: 1em;"></span><br/></li></ul><p> <a href="/">View Bio</a><br/></p></div></div>the Source public health guidelines need to go beyond hand washing, mask-wearing.<p><span style="font-size: 1.05em;">Why public health guidelines need to go beyond hand washing, mask-wearing<br/></span></p> pollution estimates reveal surprises, opportunity<img alt="" src="/news/PublishingImages/Figure4_updatedPM25.jpg?RenditionID=1" style="BORDER:0px solid;" /><div id="__publishingReusableFragmentIdSection"><a href="/ReusableContent/36_.000">a</a></div><p>​It is not unusual to come across headlines about pollution or global warming and find that they reach different conclusions depending upon the data source.</p><p>Researchers at Washington University in St. Louis used a harmonized approach, incorporating data from multiple satellites and ground monitors with computer modeling to compile a comprehensive, consistent map of pollution across the globe. Their data spans 1998-2018, providing a current picture of the state of the world’s air quality that reveals some surprises, both for better and for worse.</p><p>The research was led by Melanie Hammer, a postdoctoral research fellow in the lab of <a href="/Profiles/Pages/Randall-Martin.aspx">Randall Martin</a>, professor of energy, environmental and chemical engineering in the McKelvey School of Engineering.<br/></p><p>Results of their study that looked at PM2.5 — tiny particles that are able to make their way deep into a person’s respiratory system — were published June 3 in <a href="">Environmental Science & Technology</a>.</p><p>“Prior studies that look at long-term PM2.5 haven’t used data as recent as we have,” Hammer said. Older data can’t capture the results of many programs aimed at curbing pollution — even if they have been in effect for nearly a decade.</p><p>That turned out to be the case in China, where a significant drop in pollution in the recent past was the result of strategies begun in earnest around 2011. Other data sets don’t capture the drop.</p><p>And in India — another area of concern — the story was not as positive. “It seems there’s a bit of a plateau of PM2.5 levels,” Hammer said. Though still, levels are not rising as steeply as other reports may suggest.</p><p>PM2.5 refers to the size of particles — 2.5 microns. These tiny particles are created in nature, but also by human activities, including some manufacturing processes, car exhaust and the use of wood-burning cookstoves.<br/></p><p>It’s not easy to measure the amount of PM2.5 on the ground because there isn’t any kind of comprehensive monitoring network covering the globe. North America and Europe have extensive monitoring systems, as does China. But, Martin said, “There are large gaps in ground-based monitoring. People can be living hundreds of kilometers away from monitors.”</p><p>To develop a comprehensive pollution map, then, ground-based monitors are simply insufficient.</p><p>To capture a global snapshot, Martin’s team started with satellite images of columns of atmosphere that spanned the ground to the edge of space. Using the established GEOS-Chem model, which simulates atmospheric composition, they could infer how much PM2.5 should be on the ground, at the bottom of any given column.</p><p>When comparing the predictions to actual levels measured by ground monitors, the agreement was striking. In fact, Martin said, “It’s the best level of agreement found to date.”</p><p>But the researchers still went a step further.</p><p>The agreement was great, but not perfect. So Hammer added the differences between the observed and predicted amounts of PM2.5 and expanded the ground-based predictions across the globe, filling in the massive gaps between monitors.</p><p>This extra step brought the observed and predicted levels of PM2.5 from 81% to 90% agreement.</p><p>Once they were able to take a good look at the most recent pollution levels around the world, the researchers saw some stark changes from previous trends. Particularly in China.</p><p>“We’re used to seeing just large, increasing trends in pollution,” Hammer said. But in China, “What we found, from 2011 to 2018, is that there actually is a particularly large negative trend.”</p><p>Elsewhere in Asia, the picture wasn’t as positive.</p><p>While pollution levels did not seem to be increasing in India, the country seems to be in a plateau phase. “The broad plateau of very high concentrations, to which a large population is exposed, is quite concerning,” Martin said. “It affects the health of a billion people.”</p><p>However, the takeaway from this research can be, on the balance, a hopeful one: It seems to show one possible way forward.</p><p>“The data Melanie’s analysis reveals is a real success story for air quality controls,” Martin said. “It shows they can be remarkably effective at reducing PM2.5.” Although scientists have known these controls contain the potential to make an impact, he said, “The changes in China are very dramatic, larger than we have seen anywhere in the world over the observational record.</p><p>“It illustrates a real opportunity to improve air quality through effective controls.”<br/></p><SPAN ID="__publishingReusableFragment"></SPAN><p>This work was supported by the Natural Sciences and Engineering Research Council (NSERC), the Energy Policy Institute at the University of Chicago, and the Health Effects Institute. It was partially supported by the Killam Trusts. GEOS-Chem input files were obtained from the GEOS-Chem Data Portal enabled by Compute Canada.<br/></p><div><div class="cstm-section"><h3>Randall Martin<br/></h3><div style="text-align: center;"> <strong><a href="/Profiles/Pages/Randall-Martin.aspx"><img src="/Profiles/PublishingImages/Randall%20Martin%202019.jpg?RenditionID=3" alt="" style="margin: 5px;"/></a> <br/></strong></div><ul style="text-align: left;"><li>Professor<br/></li><li>Research: Focuses on characterizing atmospheric composition to inform effective policies surrounding major environmental and public health challenges ranging from air quality to climate change. <br/></li></ul><p style="text-align: center;"> <a href="/Profiles/Pages/Randall-Martin.aspx">>> View Bio</a><br/></p></div></div><div><div class="cstm-section"><h3>Pollution, health around the world</h3><p> <sub> In people already sick with illness such as asthma, PM2.5 can have immediate health consequences. Long-term, however, breathing in these particles carries consequences for everyone.</sub></p><p></p><p> <sub>“PM2.5 is a major public health concern globally,” said Melanie Hammer, postdoctoral researcher in the lab of Randall Martin in the McKelvey School of Engineering. “It’s important to get accurate exposure estimates to estimate health impacts.” </sub> </p><p> <sub>That’s why organizations, including World Health Organization and Global Burden of Disease, use data from Martin’s lab.</sub></p></div></div><div class="cstm-section"><h3>Media Coverage<br/></h3><div> <strong>Free News: </strong> <a href="">The most detailed map of emissions of harmful particles around the world since 1998</a><br/></div><div><br/></div><div> <strong>Digital Journal: </strong> <a href="">New insights into atmospheric pollution sound warning bells</a><br/></div></div>Calculated trends in geophysical PM2.5 values from 1998–2018. Warm colors indicate positive trends, cool colors indicate negative trends and the opacity of the colors indicates the statistical significance of the trends. (Courtesy: Martin Lab)Brandie Jefferson’ hybrid dataset includes satellite images, modeling and air samples<p>​Researchers’ hybrid dataset includes satellite images, modeling and air samples<br/></p>