Doctoral theses
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Identifier |
000457354 |
Title |
Biomass burning tracers in the atmosphere |
Alternative Title |
Ιχνηθέτες καύσης βιομάζας στην ατμόσφαιρα |
Author
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Τσιόδρα, Ειρήνη-Ζαχαρούλα Γ.
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Thesis advisor
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Μιχαλόπουλος, Νικόλαος
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Reviewer
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Νένες, Αθανάσιος
Κανακίδου, Μαρία
Περγαντής, Σπύρος
Σπύρος, Απόστολος
Πανδής, Σπυρίδων
Μπουγιατιώτη, Αικατερίνη
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Abstract |
Polycyclic aromatic hydrocarbons (PAHs) are organic semi-volatile molecules with more than 2 fused
aromatic rings structure originating from incomplete combustion processes, mainly of anthropogenic
origin. Their presence in the atmosphere plays a significant role due to their health effects. PAHs and
their oxygenated derivatives (OPAHs) are related to both carcinogenic and non-carcinogenic impact
on human health making their monitoring required for assessing air quality especially in populated
areas. PAHs and OPAHs are linked to biomass burning emissions. The increasing trend of biomass
burning use of for domestic heating throughout the last decade in many European countries, and the
increased prevalence of wildfires affects the air quality of cities throughout the world. During this
study the PAHs and OPAH levels were studied in the urban environment of Athens, Greece in
yearlong measurement campaigns in order to characterize their seasonality, sources and carcinogenic
risk. The levels of measured substances were studied concurrently with other PM tracers and through
Positive Matrix Factorization analysis their sources were assessed. Biomass burning and traffic
related sources such as gasoline and oil/diesel combustion are found to be the major contributors to
PAHs and OPAHs concentrations (biomass burning: 44% & 69% to PAHs and OPAHs, traffic: 53% &
25% to PAHs and OPAHs, respectively) while limited role is given to non-local sources. Regarding
their toxicity, it was demonstrated that the carcinogenic risk is considerable elevated and a significant
percentage of it is associated with biomass burning, and levels are above.
Throughout the sampling period, certain case studies were examined, one of them being the winter
intense pollution events (IPEs). During winter seasons some days with low wind speed, absence of
precipitation and high black carbon (BC) levels, the concentration of PAHs and OPAHs were
significantly higher compared to the non-IPE events (factor of 10). These IPEs were detected in all the
four winter seasons examined (2016-2017, 2017-2018, 2018-2019, 2020-2021). Another case study
focuses on the years of 2020-2021 when the restrictions on traffic for the limitation of COVID-19
spread, reduced the PAHs and OPAHs levels. Finally, a third study refers to a wildfire event that was
recorded during May 2021 in a forest area close to Athens and constitutes an example of how wildfire
events, a phenomenon that tends to have an increased frequency globally due to climate change,
affects the air quality of neighboring urban center.
The importance of biomass burning emissions as a source of PAHs and OPAHs lead to the further
investigation of this factor through a series of experiments in the FORTH atmospheric simulation
chamber. Fuels such as logs from olive wood (hardwood) and wood pellets were burned using a
range of appliances and the emitted smoke was studied in detail. The fresh emissions were
subsequently aged through two different methods for the characterization of the daytime and night
time aging of the plume. In addition, the combustion source was studied under flaming &
smouldering conditions and the PAH, OPAH profiles were measured in each case. Furthermore, the
impact of relative humidity inside the simulation chamber was examined showing that it strongly
affects the PAHs and OPAHs levels by decreasing them 6 and 17 times, respectively. Diagnostic ratios
of the detected PAHs and OPAHs members were calculated under fresh and aged combustion
processes showing the transformation of the ratios through aging and finally the potential
carcinogenic risk of the two fuels and of different humidity conditions was estimated. The emissions
from wood burning combustion present 23 and 4 times higher carcinogenic risk for PAHs and OPAHs
respectively, compared to pellet combustion emissions.
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Language |
English |
Subject |
Aerosol aging |
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Chamber experiments |
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OPAHs |
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PAHs |
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Risk Assessment |
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Source apportionment |
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Γήρανση αερολυμάτων |
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Εκτίμηση Κινδύνου |
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ΟΠΑΥ |
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ΠΑΥ |
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Πειράματα θαλάμου |
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Προσδιορισμός πηγών |
Issue date |
2023-07-28 |
Collection
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School/Department--School of Sciences and Engineering--Department of Chemistry--Doctoral theses
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Type of Work--Doctoral theses
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Permanent Link |
https://elocus.lib.uoc.gr//dlib/8/c/5/metadata-dlib-1689663620-81189-7877.tkl
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Views |
919 |
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