I watched this lecture from @UCDavisCOE about how COVID-19 spreads in spaces like cafes & restaurants. Thought I knew everything there is to know but I was wrong.

Lemme share with you the main takeaways. (Thanks @SpecialtyCoffee for this video)

1) Droplets are overrated - the problem with images like this is that it makes you think you’re safe if you’re outside the zone where droplets like this travel.

Droplets carry virus but invisible aerosolized particles are floating in the air and carry virus too.

2) aerosols increase with breathing & talking - ~1µm (0.001mm) particles emanate from nose and mouth constantly when exhaling & speaking. These float around for HOURS and they increase as breathing or speech becomes heavier and louder.

3) plume & room - the 6-ft zone is a thing—avoiding what comes from people’s mouths.

But indoors, there’s been research about how the aerosolized particles travel & infection can spread by breathing the air that’s increasing in load by a person breathing & talking over time.

3b) in two separate studies, people in the zone with an infected person indoors where the air conditioning was recycling the air in one area & MOST in that zone got sick, none outside that zone. The viral load builds up, and merely moving air isn’t enough it needs replenishment.

4) face shields & dividers indoors don’t work - they can reduce droplet transmission but do nearly nothing to increase protection from aerosolized particles. Indoors, they’re pretty much useless and create a false sense of protection.

5) keep your mask on - if you *must* drink or eat indoors, keep your mask on unless you’re actively putting things in your mouth. EATING OR DRINKING DOES NOT MEAN YOU CAN CHAT AND TALK WITHOUT YOUR MASK.

6) keep it outside - outside is best. There’s no way for aerosolized particles to accumulate in the air (shoutout my setup on the left at @Wrecking_Ball). Shields do help protect from droplets too.

7) ventilation ventilation ventilation - if you must eat or serve indoors, maximizing airflow is crucial. It needs to be FRESH AIR, not just recirculating air.

Filtered air is the next best thing, but making the indoors as much like the outdoors as possible is still the best.

There was more, but these are the most valuable takeaways in my opinion.

Conclusion: Personally, I’m NOT dining indoors anywhere until the pandemic is over. I’m also NOT opening service indoors at our @Wrecking_Ball cafes until the pandemic is over. Period.

Oh, one more thing: Why is it @UCDavisCOE Engineering that produced this video? This illustration explains a lot.