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    <title>PNAS &amp;mdash; Paul Sutton</title>
    <link>https://personaljournal.ca/paulsutton/tag:PNAS</link>
    <description>Personal Blog</description>
    <pubDate>Tue, 05 May 2026 16:34:26 +0000</pubDate>
    <item>
      <title>Paper on Covid 19 transmission</title>
      <link>https://personaljournal.ca/paulsutton/paper-on-covid-19-transmission</link>
      <description>&lt;![CDATA[Paper on Covid 19 transmission&#xA;&#xA;I was sent this during a discussion on Mastodon about masks and how effective masks are,  when worn by people who may not put on properly,  compared to a doctor who has a team of people to ensure this happens.   Interesting discussion and nice be sent a link to an actual paper to provide some help with the discussion.&#xA;&#xA;Feel free to join / continue the discussion, however you will need to join mastodon and follow me @zleap@qoto.org to do so. &#xA;&#xA;An upper bound on one-to-one exposure to infectious human respiratory particles&#xA;&#xA;Links&#xA;&#xA;Proceedings of the National Academy of Sciences&#xA;An upper bound on one-to-one exposure to infectious human respiratory particles&#xA;Mastodon&#xA;Qoto Stem focussed Mastodon Instance&#xA;&#xA;Tags&#xA;&#xA;#Science,#Journal,#PNAS,#Article,#Research,#Covid19,#Transmission,#Mastodon.&#xA;&#xA;Bibliography Information (just for reference)&#xA;&#xA;@article {Bagherie2110117118,&#xA;&#x9;author = {Bagheri, Gholamhossein and Thiede, Birte and Hejazi, Bardia and Schlenczek, Oliver and Bodenschatz, Eberhard},&#xA;&#x9;title = {An upper bound on one-to-one exposure to infectious human respiratory particles},&#xA;&#x9;volume = {118},&#xA;&#x9;number = {49},&#xA;&#x9;elocation-id = {e2110117118},&#xA;&#x9;year = {2021},&#xA;&#x9;doi = {10.1073/pnas.2110117118},&#xA;&#x9;publisher = {National Academy of Sciences},&#xA;&#x9;abstract = {Wearing face masks and maintaining social distance are familiar to many people around the world during the ongoing SARS-CoV-2 pandemic. Evidence suggests that these are effective ways to reduce the risk of SARS-CoV-2 infection. However, it is not clear how exactly the risk of infection is affected by wearing a mask during close personal encounters or by social distancing without a mask. Our results show that face masks significantly reduce the risk of SARS-CoV-2 infection compared to social distancing. We find a very low risk of infection when everyone wears a face mask, even if it doesn{\textquoteright}t fit perfectly on the face.There is ample evidence that masking and social distancing are effective in reducing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission. However, due to the complexity of airborne disease transmission, it is difficult to quantify their effectiveness, especially in the case of one-to-one exposure. Here, we introduce the concept of an upper bound for one-to-one exposure to infectious human respiratory particles and apply it to SARS-CoV-2. To calculate exposure and infection risk, we use a comprehensive database on respiratory particle size distribution; exhalation flow physics; leakage from face masks of various types and fits measured on human subjects; consideration of ambient particle shrinkage due to evaporation; and rehydration, inhalability, and deposition in the susceptible airways. We find, for a typical SARS-CoV-2 viral load and infectious dose, that social distancing alone, even at 3.0 m between two speaking individuals, leads to an upper bound of 90\% for risk of infection after a few minutes. If only the susceptible wears a face mask with infectious speaking at a distance of 1.5 m, the upper bound drops very significantly; that is, with a surgical mask, the upper bound reaches 90\% after 30 min, and, with an FFP2 mask, it remains at about 20\% even after 1 h. When both wear a surgical mask, while the infectious is speaking, the very conservative upper bound remains below 30\% after 1 h, but, when both wear a well-fitting FFP2 mask, it is 0.4\%. We conclude that wearing appropriate masks in the community provides excellent protection for others and oneself, and makes social distancing less important.Previously published data were used for this work (https://aerosol.ds.mpg.de/). All other study data are included in the article and/or SI Appendix.},&#xA;&#x9;issn = {0027-8424},&#xA;&#x9;URL = {https://www.pnas.org/content/118/49/e2110117118},&#xA;&#x9;eprint = {https://www.pnas.org/content/118/49/e2110117118.full.pdf},&#xA;&#x9;journal = {Proceedings of the National Academy of Sciences}&#xA;&#xA;hr&#xD;&#xA;&#xD;&#xA;table&#xD;&#xA;thead&#xD;&#xA;trtda rel=&#34;me&#34; href=&#34;https://qoto.org/@zleap&#34;Mastodon/a/td&#xD;&#xA;tda href=&#34;https://wiki.ircnow.org/?n=Shelllabs.Intro&#34;ShellLabs/td&#xD;&#xA;tda href=&#34;https://joinmastodon.org/&#34;Join Mastodon/a/td/tr/thead/table&#xD;&#xA;center&#xD;&#xA;AI statement : b Consent is NOT granted to use the content of this blog for the purposes of AI training or similar activity.  Consent CANNOT be assumed, it has to be granted. /b&#xD;&#xA;/center&#xD;&#xA;&#xD;&#xA;a href=&#34;https://liberapay.com/PaulSutton/donate&#34;img alt=&#34;Donate using Liberapay&#34; src=&#34;https://liberapay.com/assets/widgets/donate.svg&#34;/a&#xD;&#xA;]]&gt;</description>
      <content:encoded><![CDATA[<p>Paper on Covid 19 transmission</p>

<p>I was sent this during a discussion on <a href="https://docs.joinmastodon.org/" rel="nofollow">Mastodon</a> about masks and how effective masks are,  when worn by people who may not put on properly,  compared to a doctor who has a team of people to ensure this happens.   Interesting discussion and nice be sent a link to an <em>actual</em> paper to provide some help with the discussion.</p>

<p>Feel free to join / continue the discussion, however you will need to join mastodon and follow me <strong><a href="https://personaljournal.ca/@/zleap@qoto.org" class="u-url mention" rel="nofollow">@<span>zleap@qoto.org</span></a></strong> to do so.</p>
<ul><li><a href="https://www.pnas.org/content/118/49/e2110117118" rel="nofollow">An upper bound on one-to-one exposure to infectious human respiratory particles</a></li></ul>

<p><strong>Links</strong></p>
<ul><li><a href="https://www.pnas.org/" rel="nofollow">Proceedings of the National Academy of Sciences</a></li>
<li><a href="https://www.pnas.org/content/118/49/e2110117118" rel="nofollow">An upper bound on one-to-one exposure to infectious human respiratory particles</a></li>
<li><a href="https://docs.joinmastodon.org/" rel="nofollow">Mastodon</a></li>
<li><a href="https;//www.qoto.org/" rel="nofollow">Qoto Stem focussed Mastodon Instance</a></li></ul>

<p><strong>Tags</strong></p>

<p><a href="/paulsutton/tag:Science" class="hashtag" rel="nofollow"><span>#</span><span class="p-category">Science</span></a>,<a href="/paulsutton/tag:Journal" class="hashtag" rel="nofollow"><span>#</span><span class="p-category">Journal</span></a>,<a href="/paulsutton/tag:PNAS" class="hashtag" rel="nofollow"><span>#</span><span class="p-category">PNAS</span></a>,<a href="/paulsutton/tag:Article" class="hashtag" rel="nofollow"><span>#</span><span class="p-category">Article</span></a>,<a href="/paulsutton/tag:Research" class="hashtag" rel="nofollow"><span>#</span><span class="p-category">Research</span></a>,<a href="/paulsutton/tag:Covid19" class="hashtag" rel="nofollow"><span>#</span><span class="p-category">Covid19</span></a>,<a href="/paulsutton/tag:Transmission" class="hashtag" rel="nofollow"><span>#</span><span class="p-category">Transmission</span></a>,<a href="/paulsutton/tag:Mastodon" class="hashtag" rel="nofollow"><span>#</span><span class="p-category">Mastodon</span></a>.</p>

<p><strong>Bibliography Information (just for reference)</strong></p>

<pre><code>@article {Bagherie2110117118,
	author = {Bagheri, Gholamhossein and Thiede, Birte and Hejazi, Bardia and Schlenczek, Oliver and Bodenschatz, Eberhard},
	title = {An upper bound on one-to-one exposure to infectious human respiratory particles},
	volume = {118},
	number = {49},
	elocation-id = {e2110117118},
	year = {2021},
	doi = {10.1073/pnas.2110117118},
	publisher = {National Academy of Sciences},
	abstract = {Wearing face masks and maintaining social distance are familiar to many people around the world during the ongoing SARS-CoV-2 pandemic. Evidence suggests that these are effective ways to reduce the risk of SARS-CoV-2 infection. However, it is not clear how exactly the risk of infection is affected by wearing a mask during close personal encounters or by social distancing without a mask. Our results show that face masks significantly reduce the risk of SARS-CoV-2 infection compared to social distancing. We find a very low risk of infection when everyone wears a face mask, even if it doesn{\textquoteright}t fit perfectly on the face.There is ample evidence that masking and social distancing are effective in reducing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission. However, due to the complexity of airborne disease transmission, it is difficult to quantify their effectiveness, especially in the case of one-to-one exposure. Here, we introduce the concept of an upper bound for one-to-one exposure to infectious human respiratory particles and apply it to SARS-CoV-2. To calculate exposure and infection risk, we use a comprehensive database on respiratory particle size distribution; exhalation flow physics; leakage from face masks of various types and fits measured on human subjects; consideration of ambient particle shrinkage due to evaporation; and rehydration, inhalability, and deposition in the susceptible airways. We find, for a typical SARS-CoV-2 viral load and infectious dose, that social distancing alone, even at 3.0 m between two speaking individuals, leads to an upper bound of 90\% for risk of infection after a few minutes. If only the susceptible wears a face mask with infectious speaking at a distance of 1.5 m, the upper bound drops very significantly; that is, with a surgical mask, the upper bound reaches 90\% after 30 min, and, with an FFP2 mask, it remains at about 20\% even after 1 h. When both wear a surgical mask, while the infectious is speaking, the very conservative upper bound remains below 30\% after 1 h, but, when both wear a well-fitting FFP2 mask, it is 0.4\%. We conclude that wearing appropriate masks in the community provides excellent protection for others and oneself, and makes social distancing less important.Previously published data were used for this work (https://aerosol.ds.mpg.de/). All other study data are included in the article and/or SI Appendix.},
	issn = {0027-8424},
	URL = {https://www.pnas.org/content/118/49/e2110117118},
	eprint = {https://www.pnas.org/content/118/49/e2110117118.full.pdf},
	journal = {Proceedings of the National Academy of Sciences}
</code></pre>

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]]></content:encoded>
      <guid>https://personaljournal.ca/paulsutton/paper-on-covid-19-transmission</guid>
      <pubDate>Sat, 11 Dec 2021 07:30:00 +0000</pubDate>
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