Náttúrufræðingurinn - 2007, Blaðsíða 46

Náttúrufræðingurinn
Since 1988 and 1998, two Burkard
traps have been run from the beginning
of May to the end of September, except
for the last three years when the starting
time was moved to mid-April because of
warmer weather and consequently an
earlier spring. Average daily pollen con-
centrations were assessed by scanning 12
transverse lines of the microscope slide,
and referring the count of that area to
1 m1 2 3 4 5 of sampled air averaged over 24
hours.
Six different definitions of the pollen
season were taken into consideration for
the grass pollen data from Reykjavik and
Akureyri (Table 1, Fig. 3 and 4). The def-
initions of Lejoly-Gabriel6 7 8 9 10 11 and Emberlin
et al.3 are based on the narrowest period;
the latter has a three day longer duration.
These two periods last for 44 and 47 days
respectively (from 9 July to 21 or 24 Aug-
ust in Reykjavik, and from 15 July 15 to
24 or 27 August in Akureyri. See Table 2).
Definitions based on a threshold value of
a pollen count of 8 and 10 give almost the
same starting time as the definition 90%
of the total annual count, hence in
Reykjavík it starts at the tum of June-July
and lasts until 26 or 30 August, while in
Akureyri it starts in the first week of July
and ends on 2 or 4 September with a sea-
son duration of 62 to 68 days. Lastly, a
definition based on the continuity of
grass pollen in the air states that the
pollen season starts on the first of seven
consecutive days with grass pollen
counts and ends on the final day of the
last seven consecutive days with grass
pollen counts. This definition provides
the widest period of the pollen season,
with 93 days in Reykjavik and 99 in Ak-
ureyri, lasting from 7 and 8 June until 18
and 23 September respectively (Table 2,
Fig. 3 and 4).
The pollen season in Reykjavík usu-
ally culminates at the end of July or beg-
inning of August, but somewhat later in
Akureyri, typically in the latter half of
August (Table 3).
The average seasonal pollen index
(SPI = annual total) is very similar at both
locations: 1660 grass pollen grains per m3
in Akureyri, and 1600 in Reykjavik
(when the year 1988 is excluded). The fig-
ure for Reykjavík rises to 1840 if the
anomalous year 1988 is included, with its
SPI of 5828. During the eight years that
pollen monitoring has been carried out in
Akureyri and throughout the last 14 ye-
ars in Reykjavík, a trend towards a hig-
her annual total is seen, and for Reykja-
vik this trend is significant (Fig. 5).
The day to day weather in Reykjavik
and Akureyri is quite dissimilar. We
have bright days in the south when
northerly winds are blowing, and con-
versely, with prevailing southerly winds
it is dry and warm in northem Iceland
due to the Föhn effect. However, despite
these climatic differences, the pollen sea-
son in both climate regions tums out to
be rather similar, on an average annual
basis. There is a difference of only a few
days in the starting date of the season
and usually it lasts somewhat longer in
the north. The summer maximum is sim-
ilar at both locations, but it appears on
average a week later in the north.
HEIMILDIR
1. Leuschner, R.M. 1992. Von Messgeraten fiir Partikel in der Luft zum
Europaischen Polleninformationsnetz. Pravention und Rehabilitation
4. 30-36.
2. Sigrún Ása Sturludóttir 1979. Talning og greining frjókoma og gróa úr
lofti frá Akureyri sumarið 1973. Óbirt rannsóknarverkefni í líffræði
1979. Háskóli íslands. 45 bls.
3. Emberlin, }., Jaeger, S., Dominguez-Vilches, E., Galan-Soldevilla, C.,
Hodal, L., Mandrioli, P., Lehtimáki, A.R., Savage, M., Spieksma, F.Th.
& Bartlett, C. 2000. Temporal and geographical variations in grass
pollen seasons in areas of Westem Europe: an analysis of season dates
at sites of the European pollen information system. Aerobiologia 16.
373-379.
4. Nilsson, S. & Persson, S. 1981. Tree pollen spectra in the Stockholm
region (Sweden), 1973-1980. Grana 20. 179-182.
5. Vega-Maray, A.M., Valencia-Barrera, R., Fernándes-Gonzáles, D. &
Fraile, R. 2003. Urticaceae pollen concentration in the atmosphere of
north westem Spain. Annals of Agricultural and Environmental
Medicine 10. 249-255.
6. Lejoly-Gabriel, M. 1978. Recherches écologiques sur la pluie pollinique
en Belgique. Acta Geographica Lovaniensia 13. 374 bls.
7. Margrét Hallsdóttir 1999. Birch pollen abundance in Reykjavík,
Iceland. Grana 38. 368-373.
8. Clot, B. 1998. Forecast of the Poaceae pollination in Zúrich and Basel
(Switzerland). Aerobiologia 14. 267-268.
9. Clot, B. 2003. Trends in airbome pollen: An overview of 21 years of
data in Neuchátel (Switzerland). Aerobiologia 19. 227-234.
10. Spieksma, F.Th.M., Corden, J.M., Detandt, M., Millington, W.M., Nikk-
els, H., Nolard, N., Schoenmakers, C.H.H., Wachter, R., de Weger,
L.A., Willems, R. & Emberlin, J. 2003. Quantitative trends in annual
totals of five common airbome pollen types (Betula, Quercus, Poaceae,
Urtica and Artemisia), at five pollen-monitoring stations in westem
Europe. Aerobiologia 19.171-184.
11. Driessen, M.N.B.M., Van Herpen, R.M.A. & Smithuis, L.O.M.J. 1990.
Prediction of the start of the grass pollen season for the southem part
of the Netherlands. Grana 29. 79-86.
12. Frenguelli, G., Bricchi, E., Romano, B., Mincigrucci, G. & Spieksma
F.Th.M. 1989. A predictive study on the beginning of the pollen season
for Gramineae and Olea europea L. Aerobiologia 5. 64-70.
13. Smith, M. & Emberlin, J. 2006. A 30-day-ahead forecast model for grass
pollen in north London, United Kíngdom. Intemational Joumal of
Biometeorology 50 (4). 233-242.
14. Sánchez-Mesa, J.A., Galan, C., Martínez-Heras, J.A. & Hervás-
Martrnez, C. 2002. The use of a neural network to forecast daily grass
pollen concentration in a Mediterranean region: the southem part of
the Iberian Peninsula. Clinical & Experimental Allergy 32 (11). 1606-
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15. Rogers, C. 2005. Exciting times in Aerobiology. International
Aerobiology Newsletter 61. 1.
16. Oddur Sigurðsson, Trausti Jónsson & Tómas Jóhannesson (in press) .
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Um HÖFUNDINN
Margrét Hallsdóttir (f. 1949) lauk BS-prófi í jarðfræði
frá Háskóla íslands 1973 og doktorsprófi í ísaldarjarð-
fræði frá Háskólanum Lundi í Svíþjóð 1987. Hún
stundaði rannsóknir og kennslu við Raunvísindastofn-
un Háskólans og Háskóla íslands um 17 ára skeið en
starfar nú á Náttúrufræðistofnun íslands, þar sem hún
sér um frjómælingar og frjórannsóknir ásamt því að
vera umsjónarmaður steingervingasafns.
PÓST- OG NETFANG HÖFUNDAR/AUTHOR’S ADDRESS
Margrét Hallsdóttir
mh@ni.is
Náttúrufræðistofnun Íslands/Icelandic Institute of Natural History
Pósthólf/P.O. Box 5320
IS-125 Reykjavík
114
J