Chemistry Reference
In-Depth Information
evaluations of sales volumes and other sources of information. The report for 2011
shows the changes in the stock of different types of wood burning appliances [
21
].
According to BFE [
21
], there are currently 630,000 wood burning appliances
installed in Switzerland, the stock decreased by 8.9% since 1990. However, the
meteorologically adjusted annual use of wood increased in Switzerland by 36.9%
since 1990 to the above-mentioned 4.5 Mm
3
in 2011. In Switzerland, there is a clear
trend to larger automatic furnaces (heating power
50 kW) and the stock
increased since 1990 by 219%. In contrast, medium-sized wood fired building
heating systems (heating power
<
50 kW) decreased since 1990 by 53.9%, the
number of installed small wood stoves and fireplaces remained between 1990 and
2011 about constant (+2.9%).
>
2 Methods for Quantification of Source Impacts
2.1 Emission Measurements
Emissions from fireplaces and stoves have been reported in several studies testing
furnaces and wood fuel typical for different areas of the world. Wood smoke
emissions typical for central Europe were investigated by Schmidl et al. [
22
,
23
].
In these studies, different common European wood types were analysed to derive
chemical profiles of wood combustion emissions for various types of wood. An
overview of the fuel wood types used in the Alpine countries is given by Kistler
et al. [
24
]. In the above-mentioned emission studies, wood has been burnt in a tiled
wood stove [
22
] and in two automatically and two manually fired appliances [
23
].
The authors found a high variability for the emissions from small-scale manually
fired wood combustion appliances in the performed individual tests.
In addition to the emission studies, information on the chemical signature of PM
from wood burning is available. For example, organic aerosol mass spectral
signatures from wood burning emissions were described by Alfarra et al. [
25
] and
Weimer et al. [
26
]. Weimer et al. [
26
] found a larger influence of the burning
conditions (flaming phase and smouldering phase) on the mass spectra than of the
wood type used. Heringa et al. [
27
] have shown in smog chamber studies that
aerosol mass spectra can be used to discriminate SOAs from different sources of
precursors.
Emission studies are important for understanding the factors determining wood
burning emissions (e.g. technology, operation practise, fuel type and quality) and
for quantification of emission factors. Moreover, emission studies can provide
chemical source profiles that can be used in source apportionment approaches
such as chemical mass balance (CMB). However, data derived from emission
studies depends strongly on the conditions the measurements have been performed
(e.g. sampling temperature, applied dilution factors), and they typically do not
account for chemical changes occurring in the atmosphere (e.g. SOA formation)
