RESULTS (only a snapshot concerning the main results is given here. For a comprehensive description of the results s. Publications).  
Natural/biogenic emission datasets
Comparison anthropogenic vs natural/biogenic emissions
Uncertainty analysis
Contribution of natural/biogenic emissions to air pollution (modelling results)

Natural/biogenic emission datasets [go top]

Datasets for natural and biogenic emissions have been created for the years 1997, 2000, 2001 and 2003 in a high spatial (10km by 10km) and temporal (hourly to yearly) resolution for Europe. The input data and calculation/modelling methods are described in detail in the final report and NATAIR related publications. The data sets are available for all interested research groups (s. section Data/Publications).

The example maps below illustrate the spatial distribution of the NO emissions from agricultural soils (2001 and 2003).

Comparison anthropogenic vs natural/biogenic emissions [go top]

The results have been compared with anthropogenic emissions (s. figure below) to assess the relative impact of natural emissions. Looking at the results for the year 2000 and two emission scenarios (Current Legislation -CLE- and Maximum Feasible Technical Reduction -MFTR-) for the year 2010 the NATAIR results indicate that NMVOC emissions from natural sources will exceed the anthropogenic emissions in the CLE and the MFTR scenarios for 2010. PM10 emissions from natural sources will have the same level as the anthropogenic emissions in the MFTR scenario for 2010. Also for SO2 the emissions from natural sources exceeds the anthropogenic emissions in the MFTR scenario, but it has to be pointed out that natural SO2 emissions presented here refer to the situation in 2000 and mainly result from volcanic acitivities which are neither constant nor predictable over time.


Uncertainty/sensitvity analysis [go top]

Within the NatAir project, the uncertainty/sensitivity assessment of emissions from natural and biogenic sources in Europe acquired a central role. For a detailed description of the methods applied to quantify errors please refer to the final report of the project (s. Publications).

The graph below shows the uncertainties for different pollutants in relationship of their contribution to emissions in the NatAir Domain (note: the NatAir NOx emissions are fully available only for EU15 countries, thus comparison to anthropogenic emissions was also performed on this level).

Very large uncertainty ranges are evident for NMVOC and PM10, exactly those sources that assume natural emissions to surpass anthropogenic emissions. Especially for the case of PM10 this seems somewhat unexpected, but may be explained by the contribution of sea salt (clearly the largest share) occurring in parts of the model domain far from any human impact or impact on humans. The uncertainty for NMVOC just reflects the high uncertainty number presented for the dominant source, emissions from natural and semi-natural vegetation.

Contribution of natural/biogenic emissions to air pollution (modelling results) [go top]

The biogenic and natural emission inventories were implemented into the CHIMERE chemistry-transport model and their impact on European air quality evaluated.

Model - observation comparisons have been carried out in order to evaluate if including new natural emission sources improves the model performance. These comparisons were performed for ozone as a major photo-oxidant pollutant, and for PM10 as the regulated particle matter target.

The maps below show as an example the modelling results for the average daily ozone maximum in summer 2003 in Europe (left: anthropogenic emissions only, right: change in ozone formation if all NatAir natural/biogenic emissions are added).

Conclusions on the impact of natural / biogenic emissions on ozone and PM:
  • natural / biogenic emissions enhance European continental summer surface daily ozone maxima by about nearly 3 ppb on the average; this impact is strongest over the Mediterranean area, and especially over the Iberian peninsula, where the average impact can reach 10 ppb. Exceedences of air quality thresholds are strongly affected by these emissions.
  • natural / biogenic emissions are particularly effective in producing ozone in combination with enhanced anthropogenic emissions, and their inclusion in the model is necessary to explain some extreme ozone events. In a particular day of August 2000 in Porto, the model predicts a contribution to ozone from natural/biogenic sources of about 80 ug/m3.
  • natural / biogenic emissions enhance European continental PM10 by 30% on the average, but as much as a factor two over the Iberian peninsula. Most important contributions come from secondary organic aerosol (SOA) formation and seas salt, while wind blown emissions are week in the NATAIR emission cadastre. The large uncertainty inherent in many of the natural/biogenic sources is highlighted.
  • for 2010 emissions, the natural / biogenic emissions impact is similar as for 2000 emissions; however, during the exceptional summer 2003 (being indicative for a warmer climate), a strongly increased effect is encountered for ozone, whereas the effect on PM10 is only regionally increased (over the Iberian Peninsula).

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