scholarly journals Volatile and intermediate-volatility organic compounds in sub-urban Paris: variability, origin and importance for SOA formation

2014 ◽  
Vol 14 (4) ◽  
pp. 4841-4904 ◽  
Author(s):  
W. Ait-Helal ◽  
A. Borbon ◽  
S. Sauvage ◽  
J. A. de Gouw ◽  
A. Colomb ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Organic Compounds ◽  
Integrated Approach ◽  
Anthropogenic Sources ◽  
Time Resolved ◽  
Times Series ◽  
First Time ◽  
Ambient Measurements

Abstract. Measurements of gaseous and particulate organic carbon were performed during the MEGAPOLI experiments, in July 2009 and January–February 2010, at the SIRTA observatory in sub-urban Paris. Measurements of primary and secondary volatile organic compounds (VOCs), of both anthropogenic and biogenic origins, including for the first time C12-C16 n-alkanes of intermediate volatility (IVOCs), suspected to be efficient precursors of secondary organic aerosol (SOA). The time series of gaseous carbon are generally consistent with times series of particulate organic carbon at regional scales and are clearly affected by meteorology and air mass origin. Concentration levels of anthropogenic VOCs in urban and sub-urban Paris were surprisingly low (2–963 ppt) compared to other megacities worldwide and to rural continental sites. Urban enhancement ratios of anthropogenic VOC pairs agree well between the urban and sub-urban Paris sites, showing the regional extent of anthropogenic sources of similar composition. Contrary to other primary anthropogenic VOCs (aromatics and alkanes), IVOCs showed lower concentrations in winter (< 5 ppt) compared to summer (13–27 ppt) in agreement with a gas-particle partitioning in favor of their transfer to the particle phase in winter. Higher concentrations of most oxygenated VOCs in winter (18–5984 ppt) suggest their dominant primary anthropogenic origin. The respective role of primary anthropogenic gaseous compounds in regional SOA formation was investigated by estimating the SOA mass concentration expected from the anthropogenic VOCs and IVOCs (I / VOCs) measured at SIRTA. From an approach based on emissions inferred from the I / VOC concentrations times the SOA formation yields', the so-called integrated approach conducted in this study, 46% of the SOA measured at SIRTA is explained by our measured concentrations of I / VOC, with 10% explained by only C12-C16 IVOCs. From results of an alternative time-resolved approach, the explained variability of the SOA concentrations is improved when the IVOCs are taken into account. Both approaches, which are based on ambient measurements of particular I / VOCs, emphasize the importance of the intermediate volatility compounds in the SOA formation, and support previous results from chamber experiments and modeling studies. The approaches results support the need to make systematic the IVOCs speciated measurement during field campaigns.

scholarly journals Volatile and intermediate volatility organic compounds in suburban Paris: variability, origin and importance for SOA formation

2014 ◽  
Vol 14 (19) ◽  
pp. 10439-10464 ◽  
Author(s):  
W. Ait-Helal ◽  
A. Borbon ◽  
S. Sauvage ◽  
J. A. de Gouw ◽  
A. Colomb ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Organic Compounds ◽  
Regional Scale ◽  
Integrated Approach ◽  
Anthropogenic Sources ◽  
Time Resolved ◽  
Times Series

Abstract. Measurements of gaseous and particulate organic carbon were performed during the MEGAPOLI experiments, in July 2009 and January–February 2010, at the SIRTA observatory in suburban Paris. Measurements comprise primary and secondary volatile organic compounds (VOCs), of both anthropogenic and biogenic origins, including C12–C16 n-alkanes of intermediate volatility (IVOCs), suspected to be efficient precursors of secondary organic aerosol (SOA). The time series of gaseous carbon are generally consistent with times series of particulate organic carbon at regional scale, and are clearly affected by meteorology and air mass origin. Concentration levels of anthropogenic VOCs in urban and suburban Paris were surprisingly low (2–963 ppt) compared to other megacities worldwide and to rural continental sites. Urban enhancement ratios of anthropogenic VOC pairs agree well between the urban and suburban Paris sites, showing the regional extent of anthropogenic sources of similar composition. Contrary to other primary anthropogenic VOCs (aromatics and alkanes), IVOCs showed lower concentrations in winter (< 5 ppt) compared to summer (13–27 ppt), which cannot be explained by the gas-particle partitioning theory. Higher concentrations of most oxygenated VOCs in winter (18–5984 ppt) suggest their dominant primary anthropogenic origin. The respective role of primary anthropogenic gaseous compounds in regional SOA formation was investigated by estimating the SOA mass concentration expected from the anthropogenic VOCs and IVOCs (I / VOCs) measured at SIRTA. From an integrated approach based on emission ratios and SOA yields, 38 % of the SOA measured at SIRTA is explained by the measured concentrations of I / VOCs, with a 2% contribution by C12–C16 n-alkane IVOCs. From the results of an alternative time-resolved approach, the average IVOC contribution to SOA formation is estimated to be 7%, which is half of the average contribution of the traditional aromatic compounds (15%). Both approaches, which are based on in situ observations of particular I / VOCs, emphasize the importance of the intermediate volatility compounds in the SOA formation, and support previous results from chamber experiments and modeling studies. They also support the need to make systematic the IVOCs' speciated measurement during field campaigns.

scholarly journals Technology as a factor in the cultural development of mankind: a study of the production nature of primitive culture

2021 ◽  
pp. 57-60
Author(s):  
Tetiana Sovhyra
Keyword(s):  
Art History ◽  
Integrated Approach ◽  
Cultural Development ◽  
Fire Control ◽  
Production Technologies ◽  
The Subject ◽  
Organization Of Production ◽  
First Time ◽  
Metal Melting

Purpose of article. Explore technological progress in the context of the development of a primitive culture. The methodology is based on an integrated approach and relies on analytical (when analyzing philosophical, art history, cultural studies literature on the subject of research), historical (when clarifying the stages of development of primitive culture), and conceptual (when analyzing the role of technology in the cultural development of mankind) research methods. The scientific novelty of the article lies in the fact that for the first time the formative role of technology in the cultural development of mankind is investigated, and also the cooperative nature of the production of artifacts of primitive culture is determined. Conclusions. As a result of the study of archaeological finds of primitive culture, it has been established that in the course of cultural evolution, tools of labor have become cultural artifacts, works of art. The emergence of production technologies (stone processing, fire control, metal melting) radically transformed the specifics of the organization of production activities, and therefore changed the course of cultural development. Therefore, in the course of the study, the formative role of technology in the formation of artistic culture was proved.

Discrete angle rotations of Bi nanoparticles embedded in a Ga matrix

Open Physics ◽  
2010 ◽  
Vol 8 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Avraham Be’er ◽  
Richard Kofman ◽  
Yossi Lereah
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Time Resolved ◽  
Transmission Electron ◽  
The Difference ◽  
First Time ◽  
Microscopy Images ◽  
Bi Nanoparticles

AbstractSpontaneous instabilities of nanoparticles are known to be influenced by the temperature, and strongly depend on the particle size. However, it is not clear what is the role of the surrounding material that is in contact with the particle. Here we report on the difference between spontaneous rotations of Bi nanoparticles embedded in amorphous SiO and those embedded in liquid Ga. The phenomenon was studied quantitatively by time resolved transmission electron microscopy using Fourier Transform analysis of highresolution electron microscopy images. While rotations of Bi nanoparticles embedded in amorphous SiO occur by all angles, the rotations of Bi nanoparticles embedded in liquid Ga occur by discrete angles. Our results point quantitatively, for the first time, to the role and importance of the contacting surrounding surface during the rotation of nanoparticles.

scholarly journals The role of effective discharge in the ocean delivery of particulate organic carbon by small, mountainous river systems

2009 ◽  
Vol 55 (1) ◽  
pp. 161-171 ◽  
Author(s):  
Robert A. Wheatcroft ◽  
Miguel A. Goñ i ◽  
Jeff A. Hatten ◽  
Gregory B. Pasternack ◽  
Jonathan A. Warrick
Keyword(s):  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
River Systems ◽  
Effective Discharge ◽  
Mountainous River

Life cycle exposure of plants considerably affects root uptake of PCBs: role of growth strategies and dissolved/particulate organic carbon variability

2021 ◽  
pp. 126826
Author(s):  
Elisa Terzaghi ◽  
Giuseppe Raspa ◽  
Elisabetta Zanardini ◽  
Cristiana Morosini ◽  
Simone Anelli ◽  
...  
Keyword(s):  
Life Cycle ◽  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Root Uptake ◽  
Growth Strategies

scholarly journals Polar organic tracers in PM<sub>2.5</sub> aerosols from forests in eastern China

2008 ◽  
Vol 8 (24) ◽  
pp. 7507-7518 ◽  
Author(s):  
W. Wang ◽  
M. H. Wu ◽  
L. Li ◽  
T. Zhang ◽  
X. D. Liu ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Organic Carbon ◽  
Organic Compounds ◽  
Meteorological Parameters ◽  
Nature Reserve ◽  
Trace Gases ◽  
Eastern China ◽  
Atmospheric Particulate Matter ◽  
Oxidation Products ◽  
Anthropogenic Sources

Abstract. Photooxidation products of biogenic volatile organic compounds, mainly isoprene and monoterpenes, are significant sources of atmospheric particulate matter in forested regions. The objectives of this study were to examine time series and diel variations of polar organic tracers for the photooxidation of isoprene and α-pinene to investigate whether they are linked with meteorological parameters or trace gases, and to determine their carbon contributions. In addition, the biogenic secondary organic carbon contributions from isoprene were estimated. PM2.5 (particulate matter with an aerodynamic diameter <2.5 μm) aerosol samples were collected from forests in eastern China and compared with data from forested sites in Europe and America. Aerosol sampling was conducted at four sites located along a gradient of ecological succession in four different regions, i.e. Changbai Mountain Nature Reserve (boreal-temperate), Chongming National Forest Park (temperate), Dinghu Mountain Nature Reserve (subtropical) and Jianfengling Nature Reserve in Hainan (tropical) during summer periods when the meteorological conditions are believed to be favorable for photochemical processes. Fifty PM2.5 samples were collected; eighteen organic compounds, organic carbon (OC), elemental carbon and trace gases were measured. Results indicate that the concentration trends of the secondary organic compounds reflected those of the trace gases and meteorological parameters. Very good correlations between the sum concentrations of isoprene oxidation products and atmospheric SO2, O3, NO2, NOx, as well as CO2, at the Changbai site were found. The secondary OC due to isoprene was relatively high in tropical Hainan (0.27 μgC/m3) where isoprene-emitting broadleaf species are dominant, but was comparable in boreal Changbai (0.32 μgC/m3) where coniferous species are prevalent. The contribution of malic acid, which may have both biogenic and anthropogenic sources, to the OC mass was comparable at the four sites.

scholarly journals Dissolved and particulate organic carbon in Icelandic proglacial streams

2018 ◽  
Author(s):  
Peter Chifflard ◽  
Christina Fasching ◽  
Martin Reiss ◽  
Lukas Ditzel
Keyword(s):  
Organic Matter ◽  
Optical Properties ◽  
Organic Carbon ◽  
Microbial Communities ◽  
Particulate Organic Carbon ◽  
Ice Cap ◽  
Glacier Terminus ◽  
Aromatic Content ◽  
Doc Concentration ◽  
First Time

Abstract. Here for the first time, we analyze the concentration of dissolved (DOC) and particulate organic carbon (POC), as well as its optical properties (absorbance and fluorescence) in proglacial streams of Iceland, location of Europe's largest nonpolar ice cap. DOC and POC concentrations range from 0.11 mg L−1 to 0.94 mg L−1 and from 0.67 mg L−1 to 173.33 mg L−1, respectively. We estimate an annual release of 0.008 Tg C yr−1 (DOC) and 1.72 Tg C yr−1 (POC) from Icelandic glaciers. Compared to the global release of 1.97 Tg C yr−1 POC, these first calculations underline the necessity to include the Icelandic glaciers in global organic carbon budgets. Based on optical properties, we found that although glacial derived organic matter (OM) was dominated by proteinaceous florescence, organic matter composition was variable among glaciers, often exhibiting relatively higher aromatic content and increased humification closer to the glacier terminus, modulated by the presence of glacial lakes. While POC concentration decreased downstream, DOC concentration as well as the autochthonous fraction of OM increased suggesting the reworking of the OC by microbial communities, which has implications for downstream ecosystems as glaciers continue to melt.

Sign in / Sign up

Export Citation Format

Share Document