CO2 concentrations as a function of wind speed, direction, and time of day.
(A) CO2 concentrations ([CO2]) versus wind speed for summer, fall, and winter. [CO2] concentrations at zero wind speed are not shown. While variability exists, [CO2] are highest at low wind speeds and are lower and less variable at higher wind speeds. (B) Polar annulus plot of [CO2] versus wind direction and hour of the day. The 0 inside the annulus represents midnight, and 23 outside the annulus represents 23:00. Higher concentrations occur when winds are from the northwest, west, and south, with the highest concentrations occurring during the evening through the early morning hours. A secondary high occurs for southeast winds during the midday period.