A key variable regulating the trace gas exchange at the biosphere-atmosphere interface is the canopy ventilation rate. Dominant flushing mechanisms for forests are ”sweeping” large scale coherent eddies. They appear as ramp patterns in  scalar time series. Within the EUSTACH-LBA project, the exchange of energy and various trace gases between a primary Amazonian rain forest and the atmo­sphere was in­ves­ti­gated by eddy correlation and profile measurements. High frequency measurements of wind , temperature (sonic anemometer), NO, O₃, H₂O and CO₂ (chemiluminescence, and UV absorption) were performed at several heights within and above the canopy with a sampling frequency of 10 Hz or higher. Depending on the time of day, distinct ramp like patterns in this high resolution time series were frequently observed. They enable the application of  the surface renewal method, an alternative approach to determine scalar fluxes by quantification of the average storage change in the canopy volume associated with the coherent structures. A continuous wavelet transform was used to extract the information of these structures and the related canopy ventilation rates. The fluxes obtained by the surface renewal technique were compared with the results of eddy covariance measurements to validate the determined ventilation rates. The corresponding ventilation time scales were related to the time scales of (photo) chemical processes in order to explain the observed vertical distribution of NO, NO₂, and O₃ throughout the canopy.