Edge effects are a massive thing in fluid flow. I'd expect there to be a significant difference between air quality at ground level (human mouth level) and 2nd-

Edge effects are a massive thing in fluid flow. I'd expect there to be a significant difference between air quality at ground level (human mouth level) and 2nd-storey level. Isn't the turbulent flow around ground obstructions likely to make more pollutants gather in the boundary layer, and the lower flow rate ensure they're not swept away? (I don't know the answer, I'm asking a question to check my intuition)