Organic Constituents of Atmospheric Aerosols in a Hemi-boreal Forest
Date
2022
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Tartu Ülikool
Abstract
Atmospheric aerosols have been demonstrated to be a highly dynamic system, playing a significant
role in climate change and human health. In nature, ecosystems like boreal forests can modify the
atmospheric particles producing a warming or cooling effect on climate. However, the regional
and global impact of boreal forest on climate is still difficult to determine, especially due to the
heterogeneous chemistry of aerosol samples, the need for multiple instruments for identification,
and their limited library of compounds. In this thesis, to overcome these issues, we used a
molecular networking technique based on the Global Natural Products Social web platform in
combination with Nuclear Magnetic Resonance (NMR) to perform a screening of organic aerosols
during the winter spring, and summer seasons from a Hemi-boreal forest. The aerosol samples
were recollected in a glass filter weekly from SMEAR Station (Estonia) and analyzed by Gas
Chromatography Mass spectrometry and NMR. A variety of chemical functional groups including
carboxylic acids, phthalates, and organophosphate among the most abundant were annotated in the
studied seasons. Furthermore, it was analyzed the presence of n-alkanol, carboxylic acid, and nalkane to evaluate any hydrocarbon contamination. Phthalates-based compounds like Dibutyl
phthalate (~20.59% in winter), and Bis(2-ethylhexyl) phthalate (~3.87% in summer), altogether
with organophosphates like Tris(2,4-di-tert-butylphenyl) phosphate (~24.13% in spring) and
tris(2,4-di-tertbutylphenyl) phosphite (~5.13% in summer) were annotated as a possible air
pollutant. Besides that, conifer burning tracers such as 7-Oxodehydroabietic (~1.18% in spring)
and dehydroabietic acid (~0.49% in summer) were annoted. These finding presented in this work
gives an insightful impact on the atmospheric aerosol composition presented in a Hemi-boreal
forest using a straightforward and versatile technique such as molecular networking.
Description
Keywords
NMRfilter, Molecular networking, NMR, GNPS, GC/MS/EI, Organic aerosols