"Ventilation systems can create complex patterns of airflow and keep viruses aloft, so simply spacing tables six feet apart — the minimum distance that the C.D.C. advises you keep from other people..."

"... may not be sufficient to safeguard restaurant patrons.... [A]ll of the people who became sick at the restaurant in China were either at the same table as the infected person or at one of two neighboring tables. The fact that people farther away remained healthy is a hopeful hint that the coronavirus is primarily transmitted through larger respiratory droplets, which fall out of the air more quickly than smaller droplets known as aerosols, which can float for hours....  An air-conditioning unit next to Family C blew air in the southward direction across all three tables; some of the air likely bounced off the wall, back in the direction of Family C.... 'We conclude that in this outbreak, droplet transmission was prompted by air-conditioned ventilation,' the authors wrote. 'The key factor for infection was the direction of the airflow.' Harvey V. Fineberg, who leads the Standing Committee on Emerging Infectious Diseases and 21st Century Health Threats at the National Academies of Sciences, Engineering and Medicine... said restaurants should be mindful of the direction of airflow in arranging tables."

From "How Coronavirus Infected Some, but Not All, in a Restaurant/A limited study by Chinese researchers suggests the role played by air currents in spreading the illness in enclosed spaces" NYT.

From the comments over there: "The implications of this event reveal staggering problems for the commercial airline industry."

And, from a lawyer: "That air currents impact the movement of virus particles is an 'of course they do.' I spent many years litigating environmental and toxic tort cases, and needless to say we saw the spread of all types of toxic substances impacted by air currents, air handling equipment, temperature differentials within a building etc. Not really anything new here, other than they focused on a specific virus particle (SARS-CoV-2)."

ADDED: Maybe there are 2 kinds of people: The ones who will decide never to go to a restaurant again and the ones who will say I'm just going to take my chances. No, I'm thinking in that chance-taking set of people, there will still be an assessment of the chances. How crowded is the place, how far apart are the tables, are the servers masked, does it look like they are sanitizing, is there subtle air circulation, or do they have a conspicuous air conditioner mounted on the wall and bearing down on the diners?