When someone with Covid breathes out, viral particles are most concentrated right next to their nose or mouth. The further away from them, the more diffuse the virus is — that’s why we socially distance.
You can imagine the viral particles in the air, in a dense cloud directly in front of people’s faces, and the cloud becoming more sparse, as it spreads out.
Intuitively, breathing closer to someone is worse than breathing further away from them, because you’ll be breathing in more virus than if you’d taken that breath at a greater distance.
The amount of virus you breathe…