scholarly journals Nanoparticle formation by ozonolysis of inducible plant volatiles

2005 ◽  
Vol 5 (6) ◽  
pp. 1489-1495 ◽  
Author(s):  
J. Joutsensaari ◽  
M. Loivamäki ◽  
T. Vuorinen ◽  
P. Miettinen ◽  
A.-M. Nerg ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Oxidation Products ◽  
Size Distributions ◽  
Aerosol Formation ◽  
Particle Size Distributions ◽  
Organic Species ◽  
Atmospheric Nucleation ◽  
White Cabbage ◽  
Volatile Organic ◽  
Order Of Magnitude

Abstract. We present the first laboratory experiments of aerosol formation from oxidation of volatile organic species emitted by living plants, a process which for half a century has been known to take place in the atmosphere. We have treated white cabbage plants with methyl jasmonate in order to induce the production of monoterpenes and certain less-volatile sesqui- and homoterpenes. Ozone was introduced into the growth chamber in which the plants were placed, and the subsequent aerosol formation and growth of aerosols were monitored by measuring the particle size distributions continuously during the experiments. Our observations show similar particle formation rates as in the atmosphere but much higher growth rates. The results indicate that the concentrations of nonvolatile oxidation products of plant released precursors needed to induce the nucleation are roughly an order-of-magnitude higher than their concentrations during atmospheric nucleation events. Our results therefore suggest that if oxidized organics are involved in atmospheric nucleation events, their role is to participate in the growth of pre-existing molecular clusters rather than to form such clusters through homogeneous or ion-induced nucleation.

scholarly journals Nanoparticle formation by ozonolysis of inducible plant volatiles

2005 ◽  
Vol 5 (1) ◽  
pp. 1-16 ◽  
Author(s):  
J. Joutsensaari ◽  
M. Loivamäki ◽  
T. Vuorinen ◽  
P. Miettinen ◽  
A.-M. Nerg ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Oxidation Products ◽  
Size Distributions ◽  
Aerosol Formation ◽  
Particle Size Distributions ◽  
Organic Species ◽  
Atmospheric Nucleation ◽  
White Cabbage ◽  
Volatile Organic ◽  
Order Of Magnitude

Abstract. We present the first laboratory experiments of aerosol formation from oxidation of volatile organic species emitted by living plants, a process which for half a century has been known to take place in the atmosphere. We have treated white cabbage crops with methyl jasmonate in order to induce the production of monoterpenes and certain less-volatile sesqui- and homoterpenes. Ozone was introduced into the growth chamber in which the crops were placed, and the subsequent aerosol formation and growth of aerosols were monitored by measuring the particle size distributions continuously during the experiments. Our observations show similar particle formation rates as in the atmosphere but much higher growth rates. The results indicate that the concentrations of nonvolatile oxidation products of plant released precursors needed to induce the nucleation are roughly an order-of-magnitude higher than their concentrations during atmospheric nucleation events. Our results therefore suggest that atmospheric nucleation events proceed via condensation of oxidized organics on pre-existing molecular clusters rather than via their homogeneous or ion-induced nucleation.

scholarly journals Measurement report: Vertical profiling of particle size distributions over Lhasa, Tibet: Tethered balloon-based in-situ measurements and source apportionment

2021 ◽  
Author(s):  
Liang Ran ◽  
Zhaoze Deng ◽  
Yunfei Wu ◽  
Jiwei Li ◽  
Zhixuan Bai ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Particle Size ◽  
Source Apportionment ◽  
Particle Mass ◽  
Size Distributions ◽  
Aerosol Formation ◽  
Tethered Balloon ◽  
Particle Size Distributions ◽  
Secondary Aerosol

Abstract. In-situ measurements of vertically resolved particle size distributions based on a tethered balloon system were carried out for the first time in the highland city of Lhasa over the Tibetan Plateau in summer 2020, using portable optical counters for the size range of 0.124~32 μm. The vertical structure of 112 aerosol profiles was found to be largely shaped by the evolution of the boundary layer (BL), with a nearly uniform distribution of aerosols within the daytime mixing layer and a sharp decline with the height in the shallow nocturnal boundary layer. During the campaign, the average mass concentration of particulate matters smaller than 2.5 μm in aerodynamic diameter (PM2.5) within the BL was around 3 μg m−3, almost four times of the amount in the free troposphere (FT), which was rarely affected by surface anthropogenic emissions. Though there was a lower level of particle mass in the residual layer (RL) than in the BL, a similarity in particle mass size distributions (PMSDs) suggested that particles in the RL might be of the same origin as particles in the BL. This was also in consistence with the source apportionment analysis based on the PMSDs. Three distinct modes were observed in the PMSDs for the BL and the RL. One mode was exclusively coarse particles up to roughly 15 μm and peaked around 5 μm. More than 50 % of total particle mass was often contributed by coarse mode particles in this area, which was thought to be associated with local dust resuspension. The mode peaking over 0.5~0.7 μm was representative of biomass burning on religious holidays and was found to be most pronounced on holiday mornings. The contribution from the religious burning factor rose from about 25 % on non-holidays to nearly 50 % on holiday mornings. The mode dominated by particles smaller than 0.3 μm was thought to be associated with combustion related emissions and/or secondary aerosol formation. In the FT coarse mode particles only accounted for less than 10 % of the total mass and particles larger than 5 μm were negligible. The predominant submicron particles in the FT might be related to secondary aerosol formation and the aging of existed particles. To give a full picture of aerosol physical and chemical properties and better understand the origin and impacts of aerosols in this area, intensive field campaigns involving measurements of vertically resolved aerosol chemical compositions in different seasons would be much encouraged in the future.

scholarly journals Particle number concentrations and size distribution in a polluted megacity: The Delhi Aerosol Supersite study

2020 ◽  
Author(s):  
Shahzad Gani ◽  
Sahil Bhandari ◽  
Kanan Patel ◽  
Sarah Seraj ◽  
Prashant Soni ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Ultrafine Particles ◽  
Particle Number ◽  
Fine Particulate Matter ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Time Resolved ◽  
Fine Particulate ◽  
National Capital ◽  
Order Of Magnitude

Abstract. The Indian national capital, Delhi, routinely experiences some of the world's highest urban particulate matter concentrations. While fine particulate matter (PM2.5) mass concentrations in Delhi are at least an order of magnitude higher than in many western cities, the particle number (PN) concentrations are not similarly elevated. Here we report on 1.25 years of highly time resolved particle size distributions (PSD) data in the size range of 12–560 nm. We observed that the large number of accumulation mode particles – that constitute most of the PM2.5 mass – also contributed substantially to the PN concentrations. The ultrafine particles (UFP, Dp 

scholarly journals Simulation of organics in the atmosphere: evaluation of EMACv2.54 with the Mainz Organic Mechanism (MOM) coupled to the ORACLE (v1.0) submodel

2021 ◽  
Author(s):  
Andrea Pozzer ◽  
Simon Reifenberg ◽  
Vinod Kumar ◽  
Bruno Franco ◽  
Domenico Taraborrelli ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
General Circulation ◽  
Circulation Model ◽  
Organic Aerosol ◽  
Efficient Estimation ◽  
Chemical Degradation ◽  
Aerosol Formation ◽  
Organic Species ◽  
Volatile Organic ◽  
Good Agreement

Abstract. An updated and expanded representation of organics in the chemistry general circulation model EMAC (ECHAM5/MESSy for Atmospheric Chemistry) has been evaluated. First, the comprehensive Mainz Organic Mechanism (MOM) in the submodel MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere) was activated with explicit degradation of organic species up to five carbon atoms and a simplified mechanism for larger molecules. Second, the ORACLE submodel (version 1.0) considers now condensation on aerosols for all organics in the mechanism. Parameterizations for aerosol yields are used only for the lumped species that are not included in the explicit mechanism. The simultaneous usage of MOM and ORACLE allows an efficient estimation, not only of the chemical degradation of the simulated volatile organic compounds, but also of the contribution of organics to the growth and fate of (organic) aerosol, with a complexity of the mechanism largely increased compared to EMAC simulations with more simplified chemistry. The model evaluation presented here reveals that the OH concentration is well reproduced globally, while significant biases for observed oxygenated organics are present. We also investigate the general properties of the aerosols and their composition, showing that the more sophisticated and process-oriented secondary aerosol formation does not degrade the good agreement of previous model configurations with observations at the surface, allowing further research in the field of gas-aerosol interactions.

scholarly journals Explicit modelling of SOA formation from α-pinene photooxidation: sensitivity to vapour pressure estimation

2011 ◽  
Vol 11 (3) ◽  
pp. 10121-10158 ◽  
Author(s):  
R. Valorso ◽  
B. Aumont ◽  
M. Camredon ◽  
T. Raventos-Duran ◽  
C. Mouchel-Vallon ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Vapour Pressure ◽  
Estimation Method ◽  
Organic Aerosol ◽  
Reaction Scheme ◽  
Oxidation Products ◽  
Organic Species ◽  
Structure Activity ◽  
Volatile Organic ◽  
Kinetics Of

Abstract. The sensitivity of the formation of secondary organic aerosol (SOA) to the estimated vapour pressures of the condensable oxidation products is explored. A highly detailed reaction scheme was generated for α-pinene photooxidation using the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A). Vapour pressures (Pvap) were estimated with three commonly used structure activity relationships. The values of Pvap were compared for the set of secondary species generated by GECKO-A to describe α-pinene oxidation. Discrepancies in the predicted vapour pressures were found to increase with the number of functional groups borne by the species. For semi-volatile organic compounds (i.e. organic species of interest for SOA formation), differences in the predicted Pvap range between a factor of 5 to 200 in average. The simulated SOA concentrations were compared to SOA observations in the Caltech chamber during three experiments performed under a range of NOx conditions. While the model captures the qualitative features of SOA formation for the chamber experiments, SOA concentrations are systematically overestimated. For the conditions simulated, the modelled SOA speciation appears to be rather insensitive to the Pvap estimation method.

scholarly journals Measurements of organic gases during aerosol formation events in the boreal forest atmosphere during QUEST

2005 ◽  
Vol 5 (2) ◽  
pp. 373-384 ◽  
Author(s):  
K. Sellegri ◽  
M. Hanke ◽  
B. Umann ◽  
F. Arnold ◽  
M. Kulmala
Keyword(s):  
Chemical Ionization ◽  
Trace Gases ◽  
Organic Aerosol ◽  
Oxidation Products ◽  
Ionization Mass ◽  
Aerosol Formation ◽  
Volatile Organic ◽  
Project Quest ◽  
Organic Gases ◽  
Organic Trace

Abstract. Biogenic VOCs are important in the growth and possibly also in the early stages of formation of atmospheric aerosol particles. In this work, we present 10 min-time resolution measurements of organic trace gases at Hyytiälä, Finland during March 2002. The measurements were part of the project QUEST (Quantification of Aerosol Nucleation in the European Boundary Layer) and took place during a two-week period when nucleation events occurred with various intensities nearly every day. Using a ground-based Chemical Ionization Mass Spectrometer (CIMS) instrument, the following trace gases were detected: acetone, TMA, DMA, mass 68amu (candidate=isoprene), monoterpenes, methyl vinyl ketone (MVK) and methacrolein (MaCR) and monoterpene oxidation products (MTOP). For all of them except for the amines, we present daily variations during different classes of nucleation events, and non-event days. BVOC oxidation products (MVK, MaCR and MTOP) show a higher ratio to the CS on event days compared to non-event days, indicating that their abundance relative to the surface of aerosol available is higher on nucleation days. Moreover, BVOC oxidation products are found to show significant correlations with the condensational sink (CS) on nucleation event days, which indicates that they are representative of less volatile organic compounds that contribute to the growth of the nucleated particles and generally secondary organic aerosol formation. Behaviors of BVOC on event and non event days are compared to the behavior of CO.

scholarly journals Temperature dependence of yields of secondary organic aerosols from the ozonolysis of α-pinene and limonene

2008 ◽  
Vol 8 (4) ◽  
pp. 15595-15664 ◽  
Author(s):  
H. Saathoff ◽  
K.-H. Naumann ◽  
O. Möhler ◽  
Å. M. Jonsson ◽  
M. Hallquist ◽  
...  
Keyword(s):  
Comprehensive Evaluation ◽  
Analytical Techniques ◽  
Oxidation Products ◽  
Volatile Product ◽  
Size Distributions ◽  
Aerosol Formation ◽  
Aerosol Dynamics ◽  
Temperature Dependences ◽  
Accommodation Coefficients ◽  
Partitioning Coefficients

Abstract. Secondary organic aerosol (SOA) formation has been investigated as a function of temperature and humidity for the ozone-initiated reaction of the two monoterpenes α-pinene (243–313 K) and limonene (253–313 K) using the 84.5 m3 aerosol chamber AIDA. This paper gives an overview of the measurements done and presents parameters specifically useful for aerosol yield calculations. The ozonolysis reaction, selected oxidation products and subsequent aerosol formation were followed using several analytical techniques for both gas and condensed phase characterisation. The effective densities of the SOA were determined by comparing mass and volume size distributions to (1.25±0.10) g cm−3 for α-pinene and (1.3±0.2) g cm−3 for limonene. The detailed aerosol dynamics code COSIMA-SOA proved to be essential for a comprehensive evaluation of the experimental results and for providing parameterisations directly applicable within atmospheric models. The COSIMA-assisted analysis succeeded to reproduce the observed time evolutions of SOA total mass, number and size distributions by adjusting the following properties of two oxidation product proxies: individual yield parameters (αi), partitioning coefficients (Ki), vapour pressures (pi) and effective accommodation coefficients (γi). For these properties temperature dependences were derived and parameterised. Vapour pressures and partitioning coefficients followed classical Clausius-Clapeyron temperature dependences. From this relationship enthalpies of vaporisation were derived for the two more and less volatile product proxies of α-pinene: (59±8) kJ mol−1 and (24±9) kJ mol−1, and limonene: (55±14) kJ mol−1 and (25±12) kJ mol−1. The more volatile proxy components had a notably low enthalpy of vaporisation while the less volatile proxy components gave enthalpies of vaporisation comparable with those of typical products from α-pinene oxidation, e.g. pinonaldehyde and pinonic acid.

scholarly journals Temperature dependence of yields of secondary organic aerosols from the ozonolysis of <i>α</i>-pinene and limonene

2009 ◽  
Vol 9 (5) ◽  
pp. 1551-1577 ◽  
Author(s):  
H. Saathoff ◽  
K.-H. Naumann ◽  
O. Möhler ◽  
Å. M. Jonsson ◽  
M. Hallquist ◽  
...  
Keyword(s):  
Comprehensive Evaluation ◽  
Analytical Techniques ◽  
Oxidation Products ◽  
Volatile Product ◽  
Size Distributions ◽  
Aerosol Formation ◽  
Aerosol Dynamics ◽  
Temperature Dependences ◽  
Accommodation Coefficients ◽  
Partitioning Coefficients

Abstract. Secondary organic aerosol (SOA) formation has been investigated as a function of temperature and humidity for the ozone-initiated reaction of the two monoterpenes α-pinene (243–313 K) and limonene (253–313 K) using the 84.5 m3 aerosol chamber AIDA. This paper gives an overview of the measurements done and presents parameters specifically useful for aerosol yield calculations. The ozonolysis reaction, selected oxidation products and subsequent aerosol formation were followed using several analytical techniques for both gas and condensed phase characterisation. The effective densities of the SOA were determined by comparing mass and volume size distributions to (1.25±0.10) g cm−3 for α-pinene and (1.3±0.2) g cm−3 for limonene. The detailed aerosol dynamics code COSIMA-SOA proved to be essential for a comprehensive evaluation of the experimental results and for providing parameterisations directly applicable within atmospheric models. The COSIMA-assisted analysis succeeded to reproduce the observed time evolutions of SOA total mass, number and size distributions by adjusting the following properties of two oxidation product proxies: individual yield parameters (αi), partitioning coefficients (Ki), vapour pressures (pi) and effective accommodation coefficients (γi). For these properties temperature dependences were derived and parameterised. Vapour pressures and partitioning coefficients followed classical Clausius – Clapeyron temperature dependences. From this relationship enthalpies of vaporisation were derived for the two more and less volatile product proxies of α-pinene: (59±8) kJ mol−1 and (24±9) kJ mol−1, and limonene: (55±14) kJ mol−1 and (25±12) kJ mol−1. The more volatile proxy components had a notably low enthalpy of vaporisation while the less volatile proxy components gave enthalpies of vaporisation comparable with those of typical products from α-pinene oxidation, e.g. pinonaldehyde and pinonic acid.

Sign in / Sign up

Export Citation Format

Share Document