Thanks for posting that (updated findings) aerosol spreading article.
I think I did finally convince her when I said something like how the CDC doesn't want to cause panic. It may also have to do with the viral loading. Standing next to somebody that breathes or coughs in your face you get more of it than what is floating in the air.
Although in a crowded area if a person breathes out and say 80% of the stuff falls to the ground within 6 feet, but 10% lingers for a few minutes, and another 10% lingers for 8 hours floating in the air. Start multiplying that 10% by all the people that have been through the area in 8 hours and it adds up!
Hence the previous suggestions (by you perhaps?) of getting to the store early in the a.m.