To provide a general method for the assessment of biogenic and anthropogenic contribution to ambient VOC, based on radiocarbon (14C) determination.


Abatement strategies to control tropospheric ozone levels in Europe are dependent on adequate information on
source strengths of ozone precursors, nitrogen oxides and volatile organic compounds (VOC). A serious lack
of data on the sources of volatile organic compounds exists, even to the point that insufficient information is
available about the ratio of biogenic and anthropogenic emissions. With present-day approaches, i.e., usage of
emission inventories, field experiments for VOC flux measurements and network monitoring of VOC
concentrations, a tremendous amount of effort will be required before effective abatement strategies may be
formulated. Methods for validation of these approaches are therefore urgently needed.
Two types of VOC (non-methane hydrocarbons and carbonyls) will be sampled from air for 14C analysis. The
14C-content of biogenic VOC equals 14C of contemporary carbon dioxide which is precisely known.
Contrary, by far the most of the anthropogenic VOC sources are of fossil origin with zero 14C-content. This
makes 14C a very interesting tracer for discriminating biogenic and anthropogenic contributions to ambient
VOC. Air samples will be taken at locations in Italy, Portugal, Germany and The Netherlands mainly during
Summer and Winter season, representing the extremes in both anthropogenic and biogenic emissions. Most of
the sampling sites have already been well characterised in terms of VOC and oxidant concentrations within the
framework of TOR, BEMA, EMEP or other monitoring experiments. The selected sites may be regarded
characteristic for the Mediterranean area, the Iberian Peninsula and NW-Europe.
The main result of the project will be an improved understanding of biogenic and anthropogenic contribution
to ambient non-methane hydrocarbons and carbonyls, and their corresponding diurnal and seasonal cycling. This
type of information will be required for the development of effective ozone abatement strategies as well as for
the public acceptance of the counter measures to be taken.