Covid-19 outbreak associated with air conditioning in restaurant in Guangzhou

Title is misleading. This is an article in a journal published by the CDC, not a statement by the CDC.<p>The evidence that the air conditioning was responsible is circumstantial at best, and I&#x27;m somewhat skeptical. If the index patient had been located at Table C then I would find the claim more credible, but they&#x27;re claiming the air conditioner both pushed aerosolized droplets away and pulled them toward it. According to the figure the other air conditioner circulates air over a large diffuse area covering 9-10 tables, but the air conditioner in question magically only covers 3 tables and E and F get no air circulation or something. It seems like the air circulation pattern is drawn to fit the hypothesis rather than based on any principled analysis.<p>They entirely ignore other possibilities like &quot;someone from Table C walked past Table B on their way to the bathroom&#x2F;stairs&#x2F;whatever, and the index patient at Table B coughed around that time.&quot;

If you read the paper it turns out there is no actual evidence for the Air Conditioning route other than &quot;the airflow direction&quot;<p>As a matter of fact &quot;air conditioning&quot; is not even involved, the same airflow could be just as well caused by a fan or the waiters moving about carrying the air around them.<p>It is ridiculously sloppy.

Spending one hour in a small restaurant room without windows sitting next to a family who just escaped from Wuhan on January 24th is the reason for the contagion, not any AC issue. Bad title. Astute but useless study by the CDC.

How about a bit better title? - &quot;COVID-19 Outbreak Associated with airlines and public transportation to Restaurant(s)&quot;

Not surprising as many air conditioning units don&#x27;t filter the air at the level required to remove viral agents.<p>Also been reports about them and virus&#x27;s in the past.<p>But more recently <a href="https:&#x2F;&#x2F;www.telegraph.co.uk&#x2F;news&#x2F;2020&#x2F;03&#x2F;06&#x2F;air-conditioning-systems-could-spread-coronavirus-research-shows&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.telegraph.co.uk&#x2F;news&#x2F;2020&#x2F;03&#x2F;06&#x2F;air-conditioning...</a><p>But like many things, even common sense needs the data to back it up so people take note.<p>Coz we have had experts in the field of air-con say they don&#x27;t, and also experts say they do:<p><a href="https:&#x2F;&#x2F;www.straitstimes.com&#x2F;singapore&#x2F;health&#x2F;coronavirus-turn-off-air-conditioners-and-open-windows-to-reduce-risk-of-being" rel="nofollow">https:&#x2F;&#x2F;www.straitstimes.com&#x2F;singapore&#x2F;health&#x2F;coronavirus-tu...</a>

Gotta wonder at who the specialists are who deal with this sort of thing and where they come from. They&#x27;d need a complicated background of medicine crossed with physics or engineering. It seems like an obviously useful thing to specialise in so they must have a few in-house experts but it seems unlikely that a medical background would prepare people for modeling the motion of small water droplets in air. That sort of thing isn&#x27;t necessarily hard but it also isn&#x27;t trivial.

This &quot;airstream&quot; study is really interesting as it could change much of the response and protection put in place in the next few months.<p>Another thing interesting to study would be how it spread on the cruise ships.

Wouldn&#x27;t it be more accurate if the headline said &quot;A Covid-19 outbreak...&quot;<p>As it&#x27;s written, it sort of sounds like it&#x27;s implying the global pandemic was the fault of a restaurant air conditioner.

My personal hypothesis is nearly all (ie. 99%) of infections are via aerosolised droplets, and none or nearly no infections via surfaces or lack of hand washing.<p>Looking at XRays of lung tissue showing clear infection hotspots suggesting the infection has been breathed in, rather than come via the bloodstream (which would typically cause the whole lung to get infected at roughly the same time).<p>The fact that disease transmission has been dramatically slowed in places implementing facemask requirements backs this up.<p>If only we could collect more reliable data confirming or denying the above hypothesis, and we managed to confirm it, then simply saying &quot;you must wear a mask at all times outside your house&quot; would probably allow lifting all other disease spread measures.

Do Chinese not kiss and hug as a greeting for close family? It seems far more likely that it happened that way than air-borne droplets dispersed via AC.