Top PDF Relating hygroscopicity and composition of organic aerosol particulate matter

Relating hygroscopicity and composition of organic aerosol particulate matter

Relating hygroscopicity and composition of organic aerosol particulate matter

J., Donahue, N. M., George, C., Goldstein, A. H., Hamilton, J. F., Herrmann, H., Hoffmann, T., Iinuma, Y., Jang, M., Jenkin, M. E., Jimenez, J. L., Kiendler-Scharr, A., Maenhaut, W., McFiggans, G., Mentel, Th. F., Monod, A., Pr ´ev ˆot, A. S. H., Seinfeld, J. H., Surratt, J. D., Szmigielski, R., and Wildt, J.: The formation, properties and impact of secondary organic aerosol: current and emerging issues, Atmos. Chem. Phys., 9, 5155–5236, doi:10.5194/acp-

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Hygroscopicity and chemical composition of Antarctic sub-micrometre aerosol particles and observations of new particle formation

Hygroscopicity and chemical composition of Antarctic sub-micrometre aerosol particles and observations of new particle formation

volatile. High hygroscopicity is specific to sea environments only. The effect of me- teorology on the particle hygroscopicity is small, though HGF values in moist and re- cently marine air masses are generally lower. The aerosol particle hygroscopic growth factors are enhanced in polar, continental air masses mainly for two reasons: 1) Het- erogeneous aging of marine originated organic aerosol increases and 2) MSA volume

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Relating particle hygroscopicity and CCN activity to chemical composition during the HCCT-2010 field campaign

Relating particle hygroscopicity and CCN activity to chemical composition during the HCCT-2010 field campaign

of constituents or non-dissolved particle matter. However, due to these effects being included in HTDMA-derived κ calculations, we could not distinguish the specific roles of these effects in creating this gap. Therefore, extrapolating from HTDMA data to prop- erties at the point of activation should be done with great care. Finally, closure study between CCNc-measured (κ CCN ) and chemical composition (κ CCN,chem ) was performed

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Hygroscopicity and chemical composition of Antarctic sub-micrometre aerosol particles and observations of new particle formation

Hygroscopicity and chemical composition of Antarctic sub-micrometre aerosol particles and observations of new particle formation

New particle formation events were detected on 21% of the classified days. A typical feature of the events is the preference of negative ions in the initial phase of the parti- cle formation. One event day was analyser further and ion and total particle formation rates were calculated. The to- tal 2 nm particle formation rate was 1.3±0.1 cm −3 s −1 and the maximum contribution from ion-mediated particle for- mation on that day was around 30%. Growth of <1.5 nm ions, as a first phase of new particle formation, was observed at the measurement site on 21 January. Direct detection of the growth of the smallest cluster ions indicates that nucle- ation in Antarctica can occur in the boundary layer and/or in the lower troposphere. In air masses of freshly nucle- ated particles the HGF values are decreased but will increase with time in subsequent particle growth. Thus, aging of the aerosol seems to increase the particle hygroscopicity. The variation of HGF values during new particle formation and growth can be explained by two factors: 1) increased organic aerosol contribution in the initial phase of particle formation and further organic aerosol heterogeneous oxidation and con- densation, and 2) decreasing organic contribution in compar- ison to other condensing vapours following the growth of the nucleation mode. However, both cases suggest that organics, or other less hygroscopic species, participate in the particle growth process.
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Relating particle hygroscopicity and CCN activity to chemical composition during the HCCT-2010 field campaign

Relating particle hygroscopicity and CCN activity to chemical composition during the HCCT-2010 field campaign

Jimenez, J. L., Canagaratna, M. R., Donahue, N. M., Prevot, A. S. H., Zhang, Q., Kroll, J. H., DeCarlo, P. F., Allan, J. D., Coe, H., Ng, N. L., Aiken, A. C., Docherty, K. S., Ulbrich, I. M., Grieshop, A. P., Robinson, A. L., Duplissy, J., Smith, J. D., Wilson, K. R., Lanz, V. A., Hueglin, C., Sun, Y. L., Tian, J., Laaksonen, A., Raatikainen, T., Rautiainen, J., Vaattovaara, P., Ehn, M., Kulmala, M., Tomlinson, J. M., Collins, D. R., Cu- bison, M. J., E, Dunlea, J., Huffman, J. A., Onasch, T. B., Al- farra, M. R., Williams, P. I., Bower, K., Kondo, Y., Schnei- der, J., Drewnick, F., Borrmann, S., Weimer, S., Demerjian, K., Salcedo, D., Cottrell, L., Griffin, R., Takami, A., Miyoshi, T., Hatakeyama, S., Shimono, A., Sun, J. Y., Zhang, Y. M., Dzepina, K., Kimmel, J. R., Sueper, D., Jayne, J. T., Herndon, S. C., Trim- born, A. M., Williams, L. R., Wood, E. C., Middlebrook, A. M., Kolb, C. E., Baltensperger, U., and Worsnop, D. R.: Evolution of organic aerosols in the atmosphere, Science, 326, 1525–1529, doi:10.1126/science.1180353, 2009.
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Vehicular emissions of organic particulate matter in Sao Paulo, Brazil

Vehicular emissions of organic particulate matter in Sao Paulo, Brazil

dataset does not suggest that m/z 149.024 might be a unique tracer for gasohol be- cause this compound was also substantially emitted from HDV (1.363 mg g −1 of fuel, see Table 5). This can be due to the procedure used for the calculation of the HDV EF, which considers the subtraction of the LDV EF. It can be cautiously argued that m/z 149.024 may be a general tracer for aerosol from vehicles engine exhaust. However,

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Reproductive cycle of the population of European clam, Ruditapes decussatus, from Lagoa de Óbidos, Leiria, Portugal.

Reproductive cycle of the population of European clam, Ruditapes decussatus, from Lagoa de Óbidos, Leiria, Portugal.

In Portugal, the European clam (Ruditapes decussatus) is an important commercial resource, and therefore, in order to increase their exploration, more production areas need to be created. Lagoa de Óbidos is a strong candidate as a cultivation area. However, the reproductive biology of this population has not been described yet. Through monitoring the sea surface temperature, chlorophyll a and particulate organic matter and by the determination of gonadal development stages, visualized in histological preparations, gonadal index, condition index and biochemical composition (protein, glycogen and total lipids) was intended to characterize the reproductive cycle of the species R. decussatus, during 10 months of sampling (October 2014 to July 2015). The reproductive cycle of R. decussatus of Lagoa de Óbidos population followed an annual cyclicality that comprised an onset of the gametogenic cycle in late winter (January 2015 for females and February 2015 for males), a ripe stage in spring (May 2015) followed by spawning that began in end of spring/early summer that possibly extended until early autumn and a subsequent period of sexual rest during the winter (November 2014 – December 2014). During the study period the gonadal index followed the same pattern as the gonadal development. Condition index showed seasonal variations which are related to food availability (chlorophyll a). The results of both cycle of nutrients stored and nutrients utilization showed that this population exhibited an intermediate strategy (between opportunistic and conservative) that allows a rapid recovery after the reproductive effort, most likely due to the wide availability of food in the Lagoa de Óbidos. This study can help improve a sustainable management of this wild stock and is important for future aquaculture development of this species.
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Rev. bras. meteorol.  vol.26 número3

Rev. bras. meteorol. vol.26 número3

Elementary chemical composition of the total atmospheric aerosol is being widely investigated since the years 80 as well as its water-soluble chemicals composition since that represents a great portion of the total mass particles (Wang et al., 2003; Almeida et al., 2005). In addition, Adamson et al (1999) suggested that the soluble fraction of the atmospheric particulate matter is the most hazardous component concerning its toxicity potential because it is the one more eficiently adsorbed by the human body. According to Fernandez-Espinosa (2002) V, Ni, Co and Mn are metals present predominantly in the more soluble and exchanging fraction of aerosols. Voutsa and Samara (2002), in a similar study, highlighted that Cu, Ni, Mn and Zn are metal present in urban particulate matter in their more soluble forms. Works conducted in the State of São Paulo (Tavares et al., 1983; Vieira et al., 1988; Forti et al., 1990) have determined the chemical composition of the aqueous extracts of particulate matter. These studies, however, mainly focused on the evaluation of the fraction susceptible of being removed by rainfall and transferred to the soil surface. There is, thus, a lack of knowledge regarding the water-soluble inhalable fraction.
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Climatology of aerosol composition (organic versus inorganic) at nonurban sites on a west-east transect across Europe

Climatology of aerosol composition (organic versus inorganic) at nonurban sites on a west-east transect across Europe

together with sulfate, as major components of fine aerosol [Heintzenberg, 1989; Zappoli et al., 1999], there is a large uncertainty on their sources (biogenic versus anthropogenic, primary versus secondary), their complex chemical nature and optical properties [Gelencse´r, 2004]. Total carbon in atmospheric aerosol can be routinely determined. Analytical methods are able to differentiate between organic (OC, a scattering material), and elemental carbon (EC), or black carbon (BC), a light absorbing material with a graphite-type crystalline structure. Usually the term BC is used for measurements based purely on optical methods, while EC is associated with thermal analytical methods and the direct determination of carbon [Gelencse´r, 2004]. The split between OC and EC is rather arbitrary and has been a subject of controversy for the last decades [Schmid et al., 2001]. EC lies generally in the submicron range whereas OC exhibits a wider size distribution, which remains poorly documented. The hygroscopic properties of OC and EC are not well established, although laboratory studies have suggested hydrophobic behavior for fresh particles and enhancement of hygroscopicity after contact with oxidants [Gelencse´r, 2004]. Bulk OC can be divided into water soluble (WSOC) and water insoluble (WinOC) parts. The hygroscopic properties of bulk OC are widely unknown although some WSOC species like dicarboxylic acids are known to be very hygroscopic [Saxena et al., 1995].
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Characterisation of solvent extractable organic constituents in atmospheric particulate matter: an overview

Characterisation of solvent extractable organic constituents in atmospheric particulate matter: an overview

that is not determined on the black/organic carbon anal- ysis by the thermal/optical method (Pio et al. 2001a). It should be referred that a significant portion of the more polar oxygenated organic compounds are not ex- tractable by common solvents, such as dichoromethane. The organic matter that is extractable and that elutes from the chromatographic columns represents a small fraction (usually less than 10%) of the total organic ex- tract. The mass of chromatographically elutable organ- ics can be subdivided into resolved (identifiable peaks) and unresolved complex mixture, consisting above all of cyclic and branched chain hydrocarbons from the in- complete combustion of fossil fuels (Tang et al. 2006). The extractable organic fractions able to separate chro- matographically into identifiable compounds are limited to molecules with carbon atoms, in general, less than 40. Thus, macromolecular and other complex compo- nents, resulting from oligomerisation and polimerisa- tion processes, which are expected to exist in the aged aerosol particles as result of either direct emission or from secondary atmospheric particulate transformation processes, constitute an analytically non-accessible frac- tion. The bulk of organic carbon representing more hydrophilic compounds (e.g. dicarboxylic acids, sugar polyols, anhydrosugars, cellulose and humic like sub- stances) are not quantifiable by classic solvent extraction followed by GC/MS. The chromatographically identifi- able organic material consists mainly of fatty acids and aliphatic constituents, with minor amounts of alcohols, aldehydes, ketones and aromatic compounds. This char- acterisation of organic aerosol samples shows that in ru- ral and forested areas oxygenated species and products from terpenes emitted by vegetation constitute the major particulate fraction. Petroleum residues and pyrogenic constituents predominate in urban samples, standing out the aliphatic hydrocarbons and cyclic components de- rived from vehicular emissions.
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J. Braz. Chem. Soc.  vol.16 número5

J. Braz. Chem. Soc. vol.16 número5

Taking into account their atmospheric characteristics, generally under photochemical conditions, forested areas of Mediterranean countries constitute an appropriate environment to investigate the secondary organic aerosols. The objective of this study was to study in situ the aerosol composition, particularly in the photo-oxidation products of biogenic volatile organic compounds, taking into consideration anthropogenic inputs, and to explain how these compounds appear in the aerosols. Atmospheric particulate matter was collected at two sites: an Abies boressi forest in central Greece and at Giesta, a coastal-rural site in the centre of Portugal. The collected aerosol was extracted with solvents and characterised by gas chromatography and mass spectrometry. The detected secondary organics include alkene derivatives, oxo-, di- and monocarboxylic acids, oxy-aromatics, aza and thia arenes, and many terpene photo-oxidation products. This in situ experiment allowed confirming the presence of secondary constituents, which have been studied almost exclusively under simulated laboratory conditions. Some reaction pathways leading to the formation of compounds in the particulate phase from precursors are presented.
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Enzymatic biofilm digestion in soil aggregates facilitates the
release of particulate organic matter by sonication

Enzymatic biofilm digestion in soil aggregates facilitates the release of particulate organic matter by sonication

Under certain conditions POC release is indicative of soil aggregate stability. Generally, aggregate stability is charac- terized by determining the reduction in aggregate size after application of mechanical force. The commonly used meth- ods are dry and wet sieving. However, the destruction of soil aggregates by ultrasonication has an advantage over these methods, which is the quantification of the applied energy (North, 1976). It is used for studying reduction of aggregate size (Imeson and Vis, 1984) as well as detachment of oc- cluded POC (Golchin et al., 1994). Kaiser and Berhe (2014) reviewed 15 studies using ultrasonication of soil aggregates in consideration of its destructiveness to the soil mineral ma- trix and occluded POM. They found destruction of POM at applied energy levels > 60 J mL −1 , destruction of sand-sized primary particles at > 710 J mL −1 and of smaller mineral particles at even higher energy levels. We used this method of gentle POM detachment from soil aggregates to measure the oLF-SOC release as a result of mechanical force and linked it to aggregate stability. Since Cerli et al. (2012) have shown that the release of free and occluded light fractions strongly depends on soil properties like mineralogy, POM content, composition and distribution, this method is restricted to comparison of soils being similar in these properties. Hav- ing regard to this restriction, the trend for increase of oLF- SOC release over increasing enzyme additions demonstrates an alteration of soil aggregate stability.
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Relating hygroscopicity and optical properties to chemical composition and structure of secondary organic aerosol particles generated from the ozonolysis of α-pinene

Relating hygroscopicity and optical properties to chemical composition and structure of secondary organic aerosol particles generated from the ozonolysis of α-pinene

ozone into the chamber, and due to the very fast consump- tion of α-pinene, its initial concentration could not be accu- rately measured. For the yield calculations, we used the SOA mass concentration and α-pinene concentration after 5 min of reaction as initial concentrations. SOA mass concentra- tion was calculated from the SMPS number size distribution corrected for dilution and the measured particle density, as- suming homogeneous spherical particles. The SOA density of 1.2 g m −3 was estimated from the mobility mode and aero- dynamic mode obtained from the SMPS and AMS measure- ments, respectively, as described by DeCarlo et al. (2004) and Katrib et al. (2005). No significant change in the SOA density was found during the experiment. Furthermore, the retrieved value is in agreement with previous laboratory stud- ies (Shilling et al., 2008; Saathoff et al., 2009). Table 1 shows that the SOA mass concentration of SOA varied from 44 to 139 µg m −3 , resulting in calculated yields values ranging be- tween 0.07 and 0.21. The comparison between the steady- state aerosol yields determined in this study and the val- ues reported in the literature is available in the Supplement (Fig. S2).
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Loading-dependent elemental composition of &alpha;-pinene SOA particles

Loading-dependent elemental composition of &alpha;-pinene SOA particles

Fig. 2. (A) High-resolution mass spectra presented at unit mass resolution. The intensity bar at each m/z value shows in green the relative contribution of fragments containing C and H (i.e., the C x H + y family) and in pink of fragments containing C, H, and O (i.e., the C x H y O + z family). Figure S2 shows an example of the deconvolution of the high- resolution mass spectra into the relative contributions by each family (DeCarlo et al., 2006). Reaction conditions and labels are as in Fig. 1, and the high-resolution spectra were collected contemporaneously with the data collection for Fig. 1. (B) Percent contribution of the C x H + y and C x H y O + z families to the total organic signal for increasing organic particle mass loading. Lines are shown to guide the eye.
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Diagenetic alterations of amino acids and organic matter in the upper Pearl River Estuary surface sediments

Diagenetic alterations of amino acids and organic matter in the upper Pearl River Estuary surface sediments

possible explanation for these observations is that most L-amino acids are found in “conventional” proteinaceous materials, whereas DAAs are components of more re- fractory, bacterial cell-wall macromolecules, like peptidoglycan (Schleifer and Kandler, 1972). C- and N-normalized yields of individual D-enantiomers other than those of D-Asp show consistent diagenetic trends towards the decreasing physical size of OM.

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Source apportionment of the carbonaceous aerosol in Norway &ndash; quantitative estimates based on <sup>14</sup>C, thermal-optical and organic tracer analysis

Source apportionment of the carbonaceous aerosol in Norway &ndash; quantitative estimates based on <sup>14</sup>C, thermal-optical and organic tracer analysis

OCff, the carbon associated with fossil-fuels, is calculated as the difference between OC and the sum of OCBSOA, OCpbs, OCpbc and OCbb, and consists of both primary emissions (OCPOA) and secondary compounds (OCASOA). In this work, we present the further breakdown of OCff into these POA and ASOA components, albeit with the strong caveat that this is probably the most uncertain split in the source-apportionment calculations. This caveat would apply for any calculations at the end of a chain of uncertain steps, but for these components the problems are exacerbated by their nature. As discussed in Robinson et al. (2007) and Don- ahue et al. (2006), the relationships between tailpipe emis- sions of POA and OA components arising from these emis- sions are complex, involving evaporation and condensation of emitted gases and particles, chemical processing and parti- tioning. Observed OC/EC ratios which have previously been used for source-apportionment (e.g. Cabada et al., 2004; Cas- tro et al., 1999; Gelencs´er et al., 2007) cannot usually distin- guish true POA from ASOA.
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Productive characteristics of maize hybrids at different cutting heights for silage and organic matter and mineral rates in post-harvest residues

Productive characteristics of maize hybrids at different cutting heights for silage and organic matter and mineral rates in post-harvest residues

in the ionic form, waste decomposition releases it quickly and entirely (BORKERT et al., 2003). In the case of rice straw, for example, 80% of the release of this nutrient occurred in approximately 7 weeks, according to Tian et al. (1992). Jaremtchuk et al. (2006) studied potassium extraction by corn plant for silage at two cutting heights and reported that increase in the cutting height (20 to 40 cm) would return to the soil on an average 19.15% of the potassium that was extracted. This would correspond to 21.37 kg potassium chloride to recover the K content in the soil. Andrade et al. (1998b) reported that cutting at 50cm resulted in a return of 78 to 102 kg potassium chloride to the soil. Current analysis showed that potassium had the highest recycling potential at the three cutting heights (14.1, 27.8 and 49.6 kg ha -1 ). In the case of
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Carbon and nitrogen isotope variations in the water column of Lake Bled (NW Slovenia)

Carbon and nitrogen isotope variations in the water column of Lake Bled (NW Slovenia)

10 m. Lake Bled is located in an industrially, touristically and agriculturally developed area. In the past, the nutrient status of the lake was high and two amelioration projects were undertaken to improve the situation: (a) a fresh water inflow was diverted from the river Radovna and (b) anoxic water was pumped symphonically into the Jezernica. The lake became mesotrophic, however algal and cyanobacterial blooms still occur,

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Buying Behavior Of Organic Vegetables Product The Effects Of Perceptions Of Quality And Risk

Buying Behavior Of Organic Vegetables Product The Effects Of Perceptions Of Quality And Risk

quality of alternatives with regard to price within a category (Jin & Suh, 2005). Organic vegetable products have advantages and technologies related of environmental friendly. Perceived quality is not the actual quality of the brands or products. Rather, it is the consumers’ judgment about an entity’s or a service’s overall excellence or superiority (Aaker, 1991). Sometimes is directly related to the reputation of the firm that manufactures the product (Davis et al. 2003), and viewed as the degree and direction of discrepancy between consumers’ perceptions and expectations (Chen & Chang, 2005). Perceived quality and perception of quality had closer theoretical, perception defined is the mental process that persons go through in selecting, organizing and interpreting information into meaningful patterns (Truong & Yap, 2010:532). It can be interpreted that perception of quality is overall judgment of superior quality of organic products as result from selecting, organizing and interpreting form the alternative product. Measurement of customer perception of quality on organic products is divide on several things, included guarantee (origin, brand, label, variety), organoleptic characteristic (firmness, color, flavor, aroma), and external factors (damage, size, price) (Carrasco et al., 2012:1422). In other side on organic product it measured with environmental concern, environmental consideration, environmental performance, environmental image, and environmental reputation (Chen & Chang, 2013:71).
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