From the article linked above :
It’s not common to contract Covid-19 from a contaminated surface, scientists say. And fleeting encounters with people outdoors are unlikely to spread the coronavirus.
Instead, the major culprit is close-up, person-to-person interactions for extended periods. Crowded events, poorly ventilated areas and places where people are talking loudly—or singing, in one famous case—maximize the risk.
tl;dr -
Transmission via surfaces appears to be a small part of the picture.
"Aerosol" transmission - extremely small particles that can stay airborne a long time or travel more than a few feet - can happen but isn't a major source.
Droplets is the primary vector. And it apparently takes a bunch to get sick. Key dangers:
- Indoors
- Close range
- More than a few minutes
- Extra danger with poor ventilation, heavy breathing, loud talking, singing.
Odds of infecting each household member: about 20%.
I'd add:
Droplets as the main vector is likely why masks appear to be so useful. Cloth and surgical masks may not help with aerosols but they seem to matter a lot with droplets.
Outdoor is better, but not a guarantee. I'd be very concerned about being in a stationary crowd, biking or running in a group (heavy breathing for extended periods with others "downstream"), or other prolonged close exposure, especially without masks.