Modelling of Biogenic Volatile Organic Compounds Emissions over Italy

Biogenic Volatile Organic Compounds (BVOC) emitted from terrestrial vegetation account for about 90 % of the total atmospheric VOC emission and are of great importance for their role in ozone-forming reactions. BVOC are also precursors of secondary organic aerosols (BSOA) that absorb and scatter the atmospheric radiation, affect precipitations by acting as cloud condensation nuclei and affect human health. For these reasons, it is important to develop models able to estimate such emissions accurately. BVOC emissions depend on plant species distributions, emissions potentials and seasonal behaviour. This work presents a high-spatial (~1 km2) BVOC emission model based on an accurate recognition of plants over the Italian territory together with their measured basal emission potentials. The CORINE Land Cover (CLC) level IV dataset was used to identify the areas covered by agriculture, vegetation and forests. MODIS-based LAI data were used to derive the emissions' seasonality for crops and deciduous trees (growing and the leaf-on seasons). BVOC emissions estimated by the developed model were compared with those provided by MEGAN model evidencing significant differences, particularly for isoprene. Such emissions were then used to fed a Chemical Transport Model (CTM) applied over the Vesuvius area, where different BVOC vertical profiles were measured by tethered balloon soundings. The comparison between observed and predicted BVOC concentrations evidenced the capability of the developed model to estimate the biogenic emissions and highlighted the necessity of an accurate inventory of the plants present in the investigated area.