Figure 4. The ozone, VOC, water vapour, and carbon dioxide fluxes are measured at the ecosystem level using micrometeorological methods. The ecosystem level fluxes are compared with the emissions obtained by the cuvette measurements combined with a forest biomass inventory, and with ambient VOC concentrations measured in the boundary layer. The figure shows the micrometeorological mast set-up of the Finnish Meteorological Institute at Pallas, summer 1996.