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- Priestley, Michael, et al.
(författare)
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Volatility Measurements of Oxygenated Volatile Organics from Fresh and Aged Residential Wood Burning Emissions
- 2024
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Ingår i: ACS EARTH AND SPACE CHEMISTRY. - : American Chemical Society. - 2472-3452. ; 8:2, s. 159-173
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Tidskriftsartikel (refereegranskat)abstract
- Residential wood combustion (RWC) is a dominant source of anthropogenic aerosol in urban areas. Complexities in aerosol chemical composition, semivolatile behavior, and secondary processing make estimating RWC impacts on climate and air quality challenging. A chemical ionization mass spectrometer with a filter inlet for gas and aerosols measured the gas-to-particle partitioning of organic compounds emitted from log wood and pellet burning stoves. Emissions were aged in an oxidation flow reactor to assess changes in the volatilities of the secondary aerosol. Effective saturation vapor concentrations (C*) of the measured species were derived using both the measured particle-to-gas concentration ratio (P- i/G( i)) and vapor pressure measurements (p(i)( 0)) calibrated using the maximum temperature during evaporation. These were used to derive new molecular formula (MF) parameterizations and were compared to selected previous parameterization. The fresh wood stove emissions were less volatile than those of the pellet stove (particle fractions of 0.96 vs 0.69), likely caused by poorer combustion conditions, producing a greater particle sink for organic vapors. After aging, the volatility of the emissions remained broadly similar, whereas all MF parameterizations showed increasing volatility. This was likely due to the measurement techniques capturing nonideal effects of partitioning that MF parameterizations cannot.
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| 3. |
- Janhall, S., et al.
(författare)
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Traffic emission factors of ultrafine particles: effects from ambient air
- 2012
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Ingår i: Journal of Environmental Monitoring. - : Royal Society of Chemistry (RSC). - 1464-0325 .- 1464-0333. ; 14:9, s. 2488-2496
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Tidskriftsartikel (refereegranskat)abstract
- Ultrafine particles have a significant detrimental effect on both human health and climate. In order to abate this problem, it is necessary to identify the sources of ultrafine particles. A parameterisation method is presented for estimating the levels of traffic-emitted ultrafine particles in terms of variables describing the ambient conditions. The method is versatile and could easily be applied to similar datasets in other environments. The data used were collected during a four-week period in February 2005, in Gothenburg, as part of the Gote-2005 campaign. The specific variables tested were temperature (T), relative humidity (RH), carbon monoxide concentration (CO), and the concentration of particles up to 10 mm diameter (PM10); all indicators are of importance for aerosol processes such as coagulation and gas-particle partitioning. These variables were selected because of their direct effect on aerosol processes (T and RH) or as proxies for aerosol surface area (CO and PM10) and because of their availability in local monitoring programmes, increasing the usability of the parameterization. Emission factors are presented for 10-100 nm particles (ultrafine particles; EFufp), for 10-40 nm particles (EF10-40), and for 40-100 nm particles (EF40-100). For EF40-100 no effect of ambient conditions was found. The emission factor equations are calculated based on an emission factor for NOx of 1 g km(-1), thus the particle emission factors are easily expressed in units of particles per gram of NOx emitted. For 10-100 nm particles the emission factor is EFufp 1.8 x 10(15) x (1 - 0.095 x CO - 3.2 x 10(-3) x T) particles km(-1). Alternative equations for the EFs in terms of T and PM10 concentration are also presented.
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| 4. |
- Shang, D. J., et al.
(författare)
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Significant effects of transport on nanoparticles during new particle formation events in the atmosphere of Beijing
- 2023
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Ingår i: Particuology. - : Elsevier BV. - 1674-2001. ; 80, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- The mechanisms of new particle formation (NPF) events that occurred under high aerosol loadings ("polluted" NPF) in the atmosphere have been unclear, which has inhibited the precision of particle pollution control. To deepen the understanding of how the "polluted" NPF events occur, a one-month comprehensive measurement was conducted in the atmosphere of Beijing during the summer of 2016. The "clean" NPF events (frequency = 22%) (condensation sink, CS < 0.015 s-1) were found to be caused by local nucleation and growth. The "polluted" NPF events (frequency = 28%) (CS > 0.015 s-1) were influenced by both local nucleation-growth and regional transport, and the contributions from the two factors to 6-25 nm particle number concentration were 60% and 40%, respectively. This study emphasized the importance of the transport for nanoparticles in relatively polluted atmospheres, and for that the regional joint particle pollution control would be an essential policy. (c) 2023 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
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