F. Pichlmayer et al., STABLE-ISOTOPE ANALYSIS FOR CHARACTERIZATION OF POLLUTANTS AT HIGH-ELEVATION ALPINE SITES, Atmospheric environment, 32(23), 1998, pp. 4075-4085
Variations in the abundance of stable isotope of sulfur, nitrogen and
carbon in sulfate, nitrate and organic carbon, respectively, were stud
ied in snow and air samples from high-alpine sites. Their suitability
as a tool for characterizing the source regions which contribute to th
e pollution of the high-alpine areas was investigated. The contributio
ns of different sources to a specific receptor site are generally unkn
own and depend on emission patterns and meteorological conditions. Mea
sured isotope ratios reflect the actual superposition of the distinct
source types under the assumption that no major isotope fractionation
occurs during transport and deposition and that post-deposition isotop
e effects can be excluded. In order to study the relationship between
source region and isotopic pattern, daily high-volume samplings of the
atmospheric aerosol at Sonnblick (Austrian Alps, 3106 m asl) were com
bined with twice-daily backtrajectories and evaluated statistically. I
n addition, vertical snow profiles taken in pits at various locations
in the Alps were analyzed. For their interpretation, a so-called snow
calendar was constructed which relates specific snow strata to the dat
es of the respective precipitation events. Furthermore, the isotope ra
tios of hydrogen and oxygen in the snow samples were used to support t
he meteorological information. Main findings of the investigations are
regional patterns of delta(34)S in airborne sulfates, the seasonality
of nitrogen isotope composition in nitrates, and a pronounced isotopi
c difference in nitrates and sulfates of pre-industrial and modern ori
gin, respectively. This study was parr of EUROTRAC subproject ALPTRAC.
(C) 1998 Published by Elsevier Science Ltd. All rights reserved.