Observations of carbon dioxide (CO2) in urban areas are relatively rare despite the importance of CO2 as a greenhouse gas and the high concentration of CO2 sources in cities. Concentrations of CO2 measured in cities reflect a complex response of both, (a) the local anthropogenic and biogenic surface-atmosphere exchange of CO2 and (b) concentrations accumulated, diluted, or advected over time controlled by meteorological factors. This makes the interpretation of urban CO2 observations challenging.

During a one-month period in summer 2008, CO2 concentrations were continuously observed at six locations within the greater Vancouver regional metropolitan area. Measurements from urban and suburban locations are compared with background rural conditions and concentrations measured above the boundary layer. We discuss observed spatial and temporal concentration patterns in the context of local sources and sinks and their modulation by meteorological factors.