Are there any high-resolution urban CO2 concentration data sets? I gather that higher-than-ambient CO2 "domes" can form above urban areas, enhancing other local air pollution. Are there papers or datasets of average CO2 concentrations down at ground level (say 0-20 metres upwards from the ground), in the spaces between buildings - streets, parks and so on?

From what I've read, CO2 concentrations at higher levels are more temporally stable, but understate concentrations across the city; whereas monitoring stations down at street level give representative concentrations for that specific place, but are temporally highly variable, and comparisons between sites suggest that they are spatially highly variable too.
Are there papers or datasets of average CO2 concentrations down at
  ground level (say 0-20 metres upwards from the ground), in the spaces
  between buildings - streets, parks and so on?


Yes, THE URBAN CO2 DOME OF PHOENIX, ARIZONA has measurements at a height of 2 meters above ground level, 1.6 km horizontal resolution. CO2 concentrations are 555 ppm near the center of the city.

An intensive two-week study of an urban CO2 dome in Phoenix, Arizona, USA has higher resolution data along selected transects.