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Nyström, Robin
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Nyström, R., Lindgren, R., Avagyan, R., Westerholm, R., Lundstedt, S. & Boman, C. (2017). Influence of Wood Species and Burning Conditions on Particle Emission Characteristics in a Residential Wood Stove. Energy & Fuels, 31(5), 5514-5524
Open this publication in new window or tab >>Influence of Wood Species and Burning Conditions on Particle Emission Characteristics in a Residential Wood Stove
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2017 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 31, no 5, p. 5514-5524Article in journal (Refereed) Published
Abstract [en]

Emissions from small-scale residential biomass combustion are a major source of indoor and outdoor particulate matter (PM) air pollution, and the performance of stoves, boilers, and fireplaces have been shown to be influenced both by fuel properties, technology, and user behavior (firing procedures). Still, rather scarce information is available regarding the relative importance of these variables for the particle characteristics and emissions of different particulate components, e.g., soot, polycyclic aromatic hydrocarbons (PAHs), oxy-PAH, and metals. In particular, the behavior of different wood fuels under varying firing procedures and combustion conditions has not been studied thoroughly. Therefore, the objective of this work was to elucidate the influence of wood species and combustion conditions on particle emission characteristics in a typical Nordic residential wood stove. The emissions from four different wood species were investigated at two controlled combustion conditions, including nominal and high burn rates, with a focus on physical and chemical properties of the fine particulate matter. Considerably elevated carbonaceous particle emissions (soot and organics) were found during high burn rate conditions, which were associated with a shift in particle number size distribution toward a higher fraction of larger particles. In some cases, as here seen for pine, the specific fuel properties can affect the combustion performance and thereby also influence particle and PAH emissions. For the inorganic ash particles, the content in the fuel, and not burning conditions, was found to be the main determining factor, as seen by the increased emissions of alkali salts for aspen. Wood stove emission data on 11 specific oxy-PAHs, together with 45 PAHs, were combined with controlled variations of burning conditions and fuels. The oxy-PAH/PAH ratio during a high burn rate was observed to increase, suggesting an enrichment of particulate oxy-PAH. Accordingly, the main influence on emission performance and particle characteristics was seen between different burn rates, and this study clearly illustrates the major importance of proper operation to avoid unfavorable burning condition, regardless of the wood species used.

National Category
Bioenergy
Identifiers
urn:nbn:se:umu:diva-136337 (URN)10.1021/acs.energyfuels.6b02751 (DOI)000402023600098 ()
Projects
Bio4Energy
Funder
Swedish Research Council, 621-2012-3802
Available from: 2017-06-19 Created: 2017-06-19 Last updated: 2019-09-02Bibliographically approved
Ohlsson, A., Yang, B., Ekblad, A., Boman, C., Nyström, R. & Olofsson, T. (2017). Stable carbon isotope labelled carbon dioxide as tracer gas for air change rate measurement in a ventilated single zone. Building and Environment, 115, 173-181
Open this publication in new window or tab >>Stable carbon isotope labelled carbon dioxide as tracer gas for air change rate measurement in a ventilated single zone
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2017 (English)In: Building and Environment, ISSN 0360-1323, E-ISSN 1873-684X, Vol. 115, p. 173-181Article in journal (Refereed) Published
Abstract [en]

Carbon dioxide (CO2) has often been used as tracer gas for measurement of the air change rate l (h1 ) in buildings. In such measurements, a correction is required for the presence of indoor CO2, which commonly consists of atmospheric CO2 mixed with human respired CO2. Here, 13C isotope-labelled CO2 was employed as tracer gas, and cavity ring-down spectroscopy (CRDS) was used for simultaneous measurement of the two isotope analogues 12CO2 and 13CO2. This enabled the simultaneous measurement of the 13CO2 tracer gas, with correction for background 13CO2, and the concentration of indoor CO2, allowing for presence of occupants. The background correction procedure assumes that the isotope delta of the background indoor CO2 equals dB ¼ 19‰, based on the prior information that the carbon isotope ratio RB ¼ 13C/12C of all carbon in the bio-geosphere of earth is in the interval 0.010900 < RB < 0.011237. Evidence supported that l could be accurately measured, using the new 13CO2 tracer method, even when the background 13CO2 concentration varied during the measurement time interval, or when the actual dB value differed from the assumed value. The measurement uncertainty for l was estimated at 3%. Uncertainty in l due to uncertainty in RB, uRB(l), was estimated to increase with a decreasing amount of 13CO2 tracer. This indicated that at least 4 ppm tracer must be used, in order to obtain uRB(l)/l < 2%. The temporal resolution of the l measurement was 1.25/l h.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Air change rate, Ventilation efficiency, Tracer technique, Cavity ring-down spectroscopy, C-13-CO2, Isotope labelled carbon dioxide
National Category
Environmental Analysis and Construction Information Technology
Identifiers
urn:nbn:se:umu:diva-131522 (URN)10.1016/j.buildenv.2017.01.021 (DOI)000397363000015 ()
Projects
Bio4Energy
Available from: 2017-02-16 Created: 2017-02-16 Last updated: 2019-09-02Bibliographically approved
Nielsen, I. E., Eriksson, A. C., Lindgren, R., Martinsson, J., Nyström, R., Nordin, E. Z., . . . Pagels, J. (2017). Time-resolved analysis of particle emissions from residential biomass combustion: Emissions of refractory black carbon, PAHs and organic tracers. Atmospheric Environment, 165, 179-190
Open this publication in new window or tab >>Time-resolved analysis of particle emissions from residential biomass combustion: Emissions of refractory black carbon, PAHs and organic tracers
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2017 (English)In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 165, p. 179-190Article in journal (Refereed) Published
Abstract [en]

Time-resolved particle emissions from a conventional wood stove were investigated with aerosol mass spectrometry to provide links between combustion conditions, emission factors, mixing state of refractory black carbon and implications for organic tracer methods. The addition of a new batch of fuel results in low temperature pyrolysis as the fuel heats up, resulting in strong, short-lived, variable emission peaks of organic aerosol-containing markers of anhydrous sugars, such as levoglucosan (fragment at m/z 60). Flaming combustion results in emissions dominated by refractory black carbon co-emitted with minor fractions of organic aerosol and markers of anhydrous sugars. Full cycle emissions are an external mixture of larger organic aerosol-dominated and smaller thinly coated refractory black carbon particles. A very high burn rate results in increased full cycle mass emission factors of 66, 2.7, 2.8 and 1.3 for particulate polycyclic aromatic hydrocarbons, refractory black carbon, total organic aerosol and m/z 60, respectively, compared to nominal burn rate. Polycyclic aromatic hydrocarbons are primarily associated with refractory black carbon-containing particles. We hypothesize that at very high burn rates, the central parts of the combustion zone become air starved, leading to a locally reduced combustion temperature that reduces the conversion rates from polycyclic aromatic hydrocarbons to refractory black carbon. This facilitates a strong increase of polycyclic aromatic hydrocarbons emissions. At nominal burn rates, full cycle emissions based on m/z 60 correlate well with organic aerosol, refractory black carbon and particulate matter. However, at higher burn rates, m/z 60 does not correlate with increased emissions of polycyclic aromatic hydrocarbons, refractory black carbon and organic aerosol in the flaming phase. The new knowledge can be used to advance source apportionment studies, reduce emissions of genotoxic compounds and model the climate impacts of refractory black carbon, such as absorption enhancement by lensing. 

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2017
Keywords
Black carbon, PAHs, Residential biomass combustion, SP-AMS, Levoglucosan
National Category
Meteorology and Atmospheric Sciences Bioenergy
Identifiers
urn:nbn:se:umu:diva-139614 (URN)10.1016/j.atmosenv.2017.06.033 (DOI)000407665500016 ()
Projects
Bio4Energy
Available from: 2017-10-04 Created: 2017-10-04 Last updated: 2019-09-02Bibliographically approved
Nyström, R. (2016). Particle emissions from residential wood and biodiesel combustion. (Doctoral dissertation). Umeå: Umeå Universitet
Open this publication in new window or tab >>Particle emissions from residential wood and biodiesel combustion
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Emissions from anthropogenic combustion sources, such as vehicles and biomass combustion, contribute significantly to ambient particulate matter (PM) both on a local and global scale. Exposure to ambient PM and air pollution in general is linked to a variety of different health effects and it has been estimated that as many as 2.1 million premature deaths each year, due to cardiopulmonary disease and lung cancer, are caused by the changes in anthropogenic air pollution since pre-industrial times. There is today still a lack of information regarding the emissions of different specific particulate emission components, e.g. soot, polycyclic aromatic hydrocarbons (PAHs), oxy-PAHs combined with details about the behaviour of different fuels under varying combustion conditions. The overall objective of this work was to provide new knowledge regarding physical and chemical properties of PM from solid and liquid biofuels, which are important for the viewpoint of human health and atmospheric pollution. This was achieved by experimental studies of the combustion of biomass using a residential wood stove and by introducing biodiesel to an off-road engine, thereby investigating two major emission sources for PM and gaseous emissions.

From the two papers regarding biodiesel included in this thesis, it can be concluded that the introduction of the biodiesel, and potentially other renewable fuels, can in a considerable way change the exhaust particle emissions. This could have implications for the assessment of exhaust from engines running on biodiesel fuels, especially when introducing biodiesel in existing and older engines.

The results from the wood combustion research performed showed some important considerations regarding both specific particle properties and the influences of different burning conditions and fuels. One major finding, based on several of the included studies, was that a proper operation of a wood stove is of major importance to avoid unfavourable burning condition and elevated emissions of soot and organic particles, regardless of the wood species used. Some specific occasions during the burning phases in batch wise wood combustion were also identified as important for the overall emissions. The results from this research has given new specific insights into the emissions from wood stoves and should be of relevance for both technological development of residential appliances, emission testing/certification, information to users and legislation.

Place, publisher, year, edition, pages
Umeå: Umeå Universitet, 2016. p. 75
Keywords
Combustion, biomass, wood, biodiesel, particulate matter, emissions, aerosols, physicochemical properties, size distribution, PAH
National Category
Other Natural Sciences
Identifiers
urn:nbn:se:umu:diva-127460 (URN)978-91-7601-605-3 (ISBN)
Public defence
2016-12-14, N460, Naturvetarhuset, Johan Bures Väg 16, Umeå, 13:00 (Swedish)
Opponent
Supervisors
Available from: 2016-11-23 Created: 2016-11-14 Last updated: 2018-06-09Bibliographically approved
Avagyan, R., Nyström, R., Lindgren, R., Boman, C. & Westerholm, R. (2016). Particulate hydroxy-PAH emissions from a residential wood log stove using different fuels and burning conditions. Atmospheric Environment, 140, 1-9
Open this publication in new window or tab >>Particulate hydroxy-PAH emissions from a residential wood log stove using different fuels and burning conditions
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2016 (English)In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 140, p. 1-9Article in journal (Refereed) Published
Abstract [en]

Hydroxylated polycyclic aromatic hydrocarbons are oxidation products of polycyclic aromatic hydrocarbons, but have not been studied as extensively as polycyclic aromatic hydrocarbons. Several studies have however shown that hydroxylated polycyclic aromatic hydrocarbons have toxic and carcinogenic properties. They have been detected in air samples in semi urban areas and combustion is assumed to be the primary source of those compounds. To better understand the formation and occurrence of particulate hydroxylated polycyclic aromatic hydrocarbons from residential wood log stove combustion, 9 hydroxylated polycyclic aromatic hydrocarbons and 2 hydroxy biphenyls were quantified in particles generated from four different types of wood logs (birch, spruce, pine, aspen) and two different combustion conditions (nominal and high burn rate). A previously developed method utilizing liquid chromatography photo ionization tandem mass spectrometry and pressurized liquid extraction was used. Polycyclic aromatic hydrocarbons were analyzed along with hydroxylated polycyclic aromatic hydrocarbons. The hydroxylated polycyclic aromatic hydrocarbon emissions varied significantly across different wood types and burning conditions; the highest emissions for nominal burn rate were from spruce and for high burn rate from pine burning. Emissions from nominal burn rate corresponded on average to 15% of the emissions from high burn rate, with average emissions of 218 mu g/MJ(fuel) and 32.5 mu g/MJ(fuel) for high burn rate and nominal burn rate, respectively. Emissions of the measured hydroxylated polycyclic aromatic hydrocarbons corresponded on average to 28% of polycyclic aromatic hydrocarbons emissions. This study shows that wood combustion is a large emission source of hydroxylated polycyclic aromatic hydrocarbons and that not only combustion conditions, but also wood type influences the emissions of hydroxylated polycyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons. There are few studies that have determined hydroxylated polycyclic aromatic hydrocarbons in emissions from wood combustion, and it is therefore necessary to further investigate the formation, occurrence and distribution of these compounds as they are present in significant amounts in wood smoke particles.

Keywords
OH-PAHs, Hydroxy-PAHs, PAHs, Wood combustion, Wood burning, Wood log stove
National Category
Meteorology and Atmospheric Sciences Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-124830 (URN)10.1016/j.atmosenv.2016.05.041 (DOI)000380083200001 ()
Projects
Bio4Energy
Available from: 2016-10-03 Created: 2016-08-26 Last updated: 2019-09-02Bibliographically approved
Nyström, R., Sadiktsis, I., Ahmed, T. M., Westerholm, R., Koegler, J. H., Blomberg, A., . . . Boman, C. (2016). Physical and chemical properties of RME biodiesel exhaust particles without engine modifications. Fuel, 186, 261-269
Open this publication in new window or tab >>Physical and chemical properties of RME biodiesel exhaust particles without engine modifications
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2016 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 186, p. 261-269Article in journal (Refereed) Published
Abstract [en]

A major contributor to ambient particulate air pollution is exhaust from diesel engines and other vehicles, which can be linked to different adverse health effects. During the last decades, a global drive towards finding sustainable and clean bio-based alternative fuels for the transport sector has taken place and biodiesel is one of the most established alternatives today. To better assess the overall effects on a public health level when introducing biodiesel and other renewable fuels, a better understanding of the detailed exhaust particle properties, is needed. In this work, the physical and chemical properties of biodiesel exhaust particles were studied in comparison to standard diesel exhaust emissions, in an existing engine without modifications, focusing on particulate carbonaceous matter and PAH/Oxy-PAH as well as fine particle size distribution. An older off-road engine, produced between 1996 and 2004, was used with three different fuels/fuel blends; (1) 100 wt% low-sulfur standard petro diesel (SD), (2) 100 wt% rapeseed methyl ester biodiesel (B100) and (3) a blended fuel – B30 consisting of 30 wt% RME and 70 wt% SD. The study focused mainly on emissions from transient engine operation, but includes also idling conditions. The gaseous emissions measured for the biodiesel fuel were in general in accordance with previous reported data in the literature, and compared to the standard petro diesel the emissions of CO was lower while NOx emissions increased. The particulate mass concentration during transient operation was almost halved compared to when petro diesel was used and this was associated with a decrease in average particle size. The shift in particle mass and size was associated with a higher fraction of organic matter in general, considerable less PAH’s but a relative higher fraction of Oxy-PAH’s, when shifting from petro diesel to biodiesel.

Keywords
Biodiesel, RME, Diesel engine, Exhaust emissions, Particles characteristics, PAH
National Category
Energy Engineering
Identifiers
urn:nbn:se:umu:diva-127037 (URN)10.1016/j.fuel.2016.08.062 (DOI)000385318600027 ()
Funder
Bio4EnergyAFA InsuranceSwedish Heart Lung Foundation
Available from: 2016-10-26 Created: 2016-10-26 Last updated: 2018-06-09Bibliographically approved
Muala, A., Rankin, G., Sehlstedt, M., Unosson, J., Bosson, J. A., Behndig, A., . . . Sandström, T. (2015). Acute exposure to wood smoke from incomplete combustion - indications of cytotoxicity. Particle and Fibre Toxicology, 12, Article ID 33.
Open this publication in new window or tab >>Acute exposure to wood smoke from incomplete combustion - indications of cytotoxicity
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2015 (English)In: Particle and Fibre Toxicology, ISSN 1743-8977, E-ISSN 1743-8977, Vol. 12, article id 33Article in journal (Refereed) Published
Abstract [en]

Background: Smoke from combustion of biomass fuels is a major risk factor for respiratory disease, but the underlying mechanisms are poorly understood. The aim of this study was to determine whether exposure to wood smoke from incomplete combustion would elicit airway inflammation in humans. Methods: Fourteen healthy subjects underwent controlled exposures on two separate occasions to filtered air and wood smoke from incomplete combustion with PM1 concentration at 314 mu g/m(3) for 3 h in a chamber. Bronchoscopy with bronchial wash (BW), bronchoalveolar lavage (BAL) and endobronchial mucosal biopsies was performed after 24 h. Differential cell counts and soluble components were analyzed, with biopsies stained for inflammatory markers using immunohistochemistry. In parallel experiments, the toxicity of the particulate matter (PM) generated during the chamber exposures was investigated in vitro using the RAW264.7 macrophage cell line. Results: Significant reductions in macrophage, neutrophil and lymphocyte numbers were observed in BW (p < 0.01, < 0.05, < 0.05, respectively) following the wood smoke exposure, with a reduction in lymphocytes numbers in BAL fluid (< 0.01. This unexpected cellular response was accompanied by decreased levels of sICAM-1, MPO and MMP-9 (p < 0.05, < 0.05 and < 0.01). In contrast, significant increases in submucosal and epithelial CD3+ cells, epithelial CD8+ cells and submucosal mast cells (p < 0.01, < 0.05, < 0.05 and < 0.05, respectively), were observed after wood smoke exposure. The in vitro data demonstrated that wood smoke particles generated under these incomplete combustion conditions induced cell death and DNA damage, with only minor inflammatory responses. Conclusions: Short-term exposure to sooty PAH rich wood smoke did not induce an acute neutrophilic inflammation, a classic hallmark of air pollution exposure in humans. While minor proinflammatory lymphocytic and mast cells effects were observed in the bronchial biopsies, significant reductions in BW and BAL cells and soluble components were noted. This unexpected observation, combined with the in vitro data, suggests that wood smoke particles from incomplete combustion could be potentially cytotoxic. Additional research is required to establish the mechanism of this dramatic reduction in airway leukocytes and to clarify how this acute response contributes to the adverse health effects attributed to wood smoke exposure.

Keywords
Air pollution, Biomass, Bronchoscopy, Cytotoxicity, Neutrophils, Lymphocytes, Mast cells
National Category
Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-111761 (URN)10.1186/s12989-015-0111-7 (DOI)000363833500001 ()26511835 (PubMedID)2-s2.0-84945908415 (Scopus ID)
Available from: 2015-11-25 Created: 2015-11-23 Last updated: 2018-06-07Bibliographically approved
Avagyan, R., Nyström, R., Boman, C. & Westerholm, R. (2015). Determination of hydroxylated polycyclic aromatic hydrocarbons by HPLC-photoionization tandem mass spectrometry in wood smoke particles and soil samples. Analytical and Bioanalytical Chemistry, 407(16), 4523-4534
Open this publication in new window or tab >>Determination of hydroxylated polycyclic aromatic hydrocarbons by HPLC-photoionization tandem mass spectrometry in wood smoke particles and soil samples
2015 (English)In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 407, no 16, p. 4523-4534Article in journal (Refereed) Published
Abstract [en]

A simple and fast method for analysis of hydroxylated polycyclic aromatic hydrocarbons using pressurized liquid extraction and high performance liquid chromatography utilizing photoionization tandem mass spectrometry was developed. Simultaneous separation and determination of nine hydroxylated polycyclic aromatic hydrocarbons and two hydroxy biphenyls could be performed in negative mode with a run time of 12 min, including equilibration in 5 min. The calibration curves were in two concentration ranges; 1-50 ng/mL and 0.01-50 mu g/mL, with coefficients of correlation R (2) > 0.997. The limits of detection and method quantification limits were in the range of 9-56 pg and 5-38 ng/g, respectively. A two-level full factorial experimental design was used for screening of conditions with the highest impact on the extraction. The extraction procedure was automated and suitable for a large number of samples. The extraction recoveries ranged from 70 to 102 % and the matrix effects were between 92 and 104 %. The overall method was demonstrated on wood smoke particles and soil samples with good analytical performance, and five OH-PAHs were determined in the concentration range of 0.19-210 mu g/g. As far as we know, hydroxylated polycyclic aromatic hydrocarbons were determined in wood smoke and soil samples using photoionization mass spectrometry for the first time in this present study. Accordingly, this study shows that high performance liquid chromatography photoionization tandem mass spectrometry can be a good option for the determination of hydroxylated polycyclic aromatic hydrocarbons in complex environmental samples.

Place, publisher, year, edition, pages
Springer Berlin/Heidelberg, 2015
Keywords
HPLC-APPI-MS/MS, Photoionization, Hydroxylated PAHs, OH-PAHs, Wood smoke, Soil
National Category
Biochemistry and Molecular Biology Analytical Chemistry
Identifiers
urn:nbn:se:umu:diva-105246 (URN)10.1007/s00216-015-8638-x (DOI)000355152500003 ()25935668 (PubMedID)
Available from: 2015-06-24 Created: 2015-06-22 Last updated: 2018-06-07Bibliographically approved
Martinsson, J., Eriksson, A. C., Nielsen, I. E., Berg Malmborg, V., Ahlberg, E., Andersen, C., . . . Pagels, J. H. (2015). Impacts of Combustion Conditions and Photochemical Processing on the Light Absorption of Biomass Combustion Aerosol. Environmental Science and Technology, 49(24), 14663-14671
Open this publication in new window or tab >>Impacts of Combustion Conditions and Photochemical Processing on the Light Absorption of Biomass Combustion Aerosol
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2015 (English)In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, no 24, p. 14663-14671Article in journal (Refereed) Published
Abstract [en]

The aim was to identify relationships between combustion conditions, particle characteristics, and optical properties of fresh and photochemically processed emissions from biomass combustion. The combustion conditions included nominal and high burn rate operation and individual combustion phases from a conventional wood stove. Low temperature pyrolysis upon fuel addition resulted in "tar-ball" type particles dominated by organic aerosol with an absorption Angstrom exponent (AAE) of 2.5-2.7 and estimated Brown Carbon contributions of 50-70% to absorption at the climate relevant aethalometer-wavelength (520 nm). High temperature combustion during the intermediate (flaming) phase was dominated by soot agglomerates with AAE 1.0-1.2 and 85-100% of absorption at 520 nm attributed to Black Carbon. Intense photochemical processing of high burn rate flaming combustion emissions in an oxidation flow reactor led to strong formation of Secondary Organic Aerosol, with no or weak absorption. PM1 mass emission factors (mg/kg) of fresh emissions were about an order of magnitude higher for low temperature pyrolysis compared to high temperature combustion. However, emission factors describing the absorption cross section emitted per kg of fuel consumed (m(2)/kg) were of similar magnitude at 520 nm for the diverse combustion conditions investigated in this study. These results provide a link between biomass combustion conditions, emitted particle types, and their optical properties in fresh and processed plumes which can be of value for source apportionment and balanced mitigation of biomass combustion emissions from a climate and health perspective.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2015
National Category
Environmental Sciences Bioenergy
Identifiers
urn:nbn:se:umu:diva-114623 (URN)10.1021/acs.est.5b03205 (DOI)000366872300091 ()
Available from: 2016-02-05 Created: 2016-01-25 Last updated: 2018-06-07Bibliographically approved
Nordin, E. Z., Uski, O., Nyström, R., Jalava, P., Eriksson, A. C., Genberg, J., . . . Hirvonen, M.-R. (2015). Influence of ozone initiated processing on the toxicity of aerosol particles from small scale wood combustion. Atmospheric Environment, 102, 282-289
Open this publication in new window or tab >>Influence of ozone initiated processing on the toxicity of aerosol particles from small scale wood combustion
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2015 (English)In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 102, p. 282-289Article in journal (Refereed) Published
Abstract [en]

Black carbon containing emissions from biomass combustion are being transformed in the atmosphere upon processing induced by tropospheric ozone and UV. The knowledge today is very limited on how atmospheric processing affects the toxicological properties of the emissions. The aim of this study was to investigate the influence of ozone initiated (dark) atmospheric processing on the physicochemical and toxicological properties of particulate emissions from wood combustion. Emissions from a conventional wood stove operated at two combustion conditions (nominal and hot air starved) were diluted and transferred to a chamber. Particulate matter (PM) was collected before and after ozone addition to the chamber using an impactor. Detailed chemical and physical characterization was performed on chamber air and collected PM. The collected PM was investigated toxicologically in vitro with a mouse macrophage model, endpoints included: cell cycle analysis, viability, inflammation and genotoxicity. The results suggest that changes in the organic fraction, including polycyclic aromatic hydrocarbons (PAHs) are the main driver for differences in obtained toxicological effects. Fresh hot air starved emissions containing a higher organic and PAH mass-fraction affected cell viability stronger than fresh emissions from nominal combustion. The PAH mass fractions decreased upon aging due to chemical degradation. Dark aging increased genotoxicity, reduced viability and reduced release of inflammatory markers. These differences were statistically significant for single doses and typically less pronounced. We hypothesize that the alterations in toxicity upon simulated dark aging in the atmosphere may be caused by reaction products that form when PAHs and other organic compounds react with ozone and nitrate radicals.

Keywords
Biomass combustion, Polycyclic aromatic hydrocarbons, Aging, Cell studies
National Category
Environmental Sciences Meteorology and Atmospheric Sciences
Identifiers
urn:nbn:se:umu:diva-102306 (URN)10.1016/j.atmosenv.2014.11.068 (DOI)000349590300031 ()
Available from: 2015-06-24 Created: 2015-04-23 Last updated: 2018-06-07Bibliographically approved
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