Your browser does not support JavaScript!

Doctoral theses

Search command : Author="Γιαπιντζάκης"  And Author="Ιωάννης"

Current Record: 4 of 224

Back to Results Previous page
Next page
Add to Basket
[Add to Basket]
Identifier 000457354
Title Biomass burning tracers in the atmosphere
Alternative Title Ιχνηθέτες καύσης βιομάζας στην ατμόσφαιρα
Author Τσιόδρα, Ειρήνη-Ζαχαρούλα Γ.
Thesis advisor Μιχαλόπουλος, Νικόλαος
Reviewer Νένες, Αθανάσιος
Κανακίδου, Μαρία
Περγαντής, Σπύρος
Σπύρος, Απόστολος
Πανδής, Σπυρίδων
Μπουγιατιώτη, Αικατερίνη
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.
Language English
Subject Aerosol aging
Chamber experiments
OPAHs
PAHs
Risk Assessment
Source apportionment
Γήρανση αερολυμάτων
Εκτίμηση Κινδύνου
ΟΠΑΥ
ΠΑΥ
Πειράματα θαλάμου
Προσδιορισμός πηγών
Issue date 2023-07-28
Collection   School/Department--School of Sciences and Engineering--Department of Chemistry--Doctoral theses
  Type of Work--Doctoral theses
Permanent Link https://elocus.lib.uoc.gr//dlib/8/c/5/metadata-dlib-1689663620-81189-7877.tkl Bookmark and Share
Views 756

Digital Documents
No preview available

No permission to view document.
It won't be available until: 2025-07-28