The problem with "outdoor" dining was all the tents restaurants were setting up in fall/winter. And it's exactly as you imagine it, no airflow or sun exposure with the vinyl / canvas / plastic walls and roofs.
But not in LA, which was what the GP was asking about. LA's climate is fine for regular outdoor dining all year.
> no airflow
From the paper this thread is discussing, it appears that no airflow is actually lower risk; the higher risk is having directed airflow, from indoor ventilation systems, and being in the path of that airflow from an infected person (and also facing them).
Afternoon dining is pretty easy to do, but dinner seems to be problematic even in OC where I'm at.
The vinyl sided tents aren't going to have recirculated air like indoors, but yes, the air is certainly not going to be flowing the way it would with no vinyl walls.
OC beach towns are as nice as they are unaffordable, lol. I love the restaurants there, though.
The paper that started this thread notes that the only people who got infected in the indoor restaurant scenario they studied were the ones in the airflow path. Nobody else did, even though they were all in the same room with the same contained air. So this one study, at least, seems to indicate that just having contained air is lower risk; it's being in the airflow path of recirculated air that is higher risk.
That said, there is nothing in the paper that says that having uncontained air outdoors is not even lower risk than contained (but not recirculated) air.
It gets cold even in LA
The weather report for Sunday 12/6/2020 says the temperature in Los Angeles will be 60F at 6pm - and it’s not winter yet