scholarly journals Measurement report: Online measurement of gas-phase nitrated phenols utilizing a CI-LToF-MS: primary sources and secondary formation

2021 ◽  
Vol 21 (10) ◽  
pp. 7917-7932
Author(s):  
Kai Song ◽  
Song Guo ◽  
Haichao Wang ◽  
Ying Yu ◽  
Hui Wang ◽  
...  
Keyword(s):  
Gas Phase ◽  
Regional Scale ◽  
Primary Sources ◽  
Phenoxy Radical ◽  
Vehicle Exhaust ◽  
Composition Variation ◽  
Secondary Formation ◽  
Long Time ◽  
Heavy Pollution ◽  
Non Negative Matrix Factorization

Abstract. To investigate the composition, variation, and sources of nitrated phenols (NPs) in the winter of Beijing, gas-phase NPs were measured by a chemical ionization long time-of-flight mass spectrometer (CI-LToF-MS). A box model was applied to simulate the secondary formation process of NPs. In addition, the primary sources of NPs were resolved by a non-negative matrix factorization (NMF) model. Our results showed that secondary formation contributed 38 %, 9 %, 5 %, 17 %, and almost 100 % of the nitrophenol (NP), methyl-nitrophenol (MNP), dinitrophenol (DNP), methyl-dinitrophenol (MDNP or DNOC), and dimethyl-nitrophenol (DMNP) concentrations. The phenol–OH reaction was the predominant loss pathway (46.7 %) during the heavy pollution episode, which produced the phenoxy radical (C6H5O). The phenoxy radical consequently reacted with NO2 and produced nitrophenol. By estimating the primarily emitted phenol from the ratio of phenol/CO from freshly emitted vehicle exhaust, this study proposed that oxidation of primary phenol contributes much more nitrophenol (37 %) than that from benzene oxidation (<1 %) in the winter of Beijing. The latter pathway was widely used in models and might lead to great uncertainties. The source apportionment results by NMF indicated the importance of combustion sources (>50 %) to the gas-phase NPs. The industry source contributed 30 % and 9 % to DNP and MDNP, respectively, which was non-negligible. The concentration weighted trajectory (CWT) analysis demonstrated that regional transport from provinces that surround the Yellow and Bohai seas contributed more primary NPs to Beijing. Both primary sources and secondary formation at either local or regional scale should be considered when making control policies of NPs.

scholarly journals Measurement Report: Online Measurement of Gas-Phase Nitrated Phenols Utilizing CI-LToF-MS: Primary Sources and Secondary Formation

2021 ◽  
Author(s):  
Kai Song ◽  
Song Guo ◽  
Haichao Wang ◽  
Ying Yu ◽  
Hui Wang ◽  
...  
Keyword(s):  
Gas Phase ◽  
Regional Scale ◽  
Primary Sources ◽  
Phenoxy Radical ◽  
Vehicle Exhaust ◽  
Composition Variation ◽  
Secondary Formation ◽  
Long Time ◽  
Heavy Pollution ◽  
Non Negative Matrix Factorization

Abstract. To investigate the composition, variation, and sources of nitrated phenols (NPs) in the winter of Beijing, gas-phase NPs were measured by using a chemical ionization long time-of-flight mass spectrometer (CI-LToF-MS). A box model was applied to simulate the secondary formation process of NPs. In addition, the primary sources of NPs were resolved by non-negative matrix factorization (NMF) model. Our results showed that secondary formation contributed 38 %, 9 %, 5 %, 17 % and almost 100 % of the ambient nitrophenol (NP), methyl-nitrophenol (MNP), dinitrophenol (DNP), methyl-dinitrophenol (MDNP or DNOC), and dimethyl-nitrophenol (DMNP). Phenol-OH reaction was the predominant loss pathway (46.7  %) during the heavy pollution episode, which produced phenoxy radical (C6H5O). The phenoxy radical consequently reacted with NO2, and produced nitrophenol. By estimating the primarily emitted phenol from the ratio of phenol/CO from freshly emitted vehicle exhaust, this study proposed that oxidation of primary phenol contributes much more nitrophenol (37 %) than that from benzene oxidation ( 50 %) to the gas-phase NPs. The industry source contributed 30 % and 9 % to DNP and MDNP, respectively, which was non-negligible. The concentration weighted trajectory (CWT) analysis demonstrated that regional transport from provinces that surround the Yellow and Bohai Seas contributed more primary NPs to Beijing. Both primary sources and secondary formation in either local or regional scale should be considered when making NPs control policies.

scholarly journals Sustainable exploitation of temperate fish stocks

2009 ◽  
Vol 6 (1) ◽  
pp. 124-127 ◽  
Author(s):  
Henrik Sparholt ◽  
Robin M. Cook
Keyword(s):  
Species Interactions ◽  
Fishery Management ◽  
Regional Scale ◽  
Single Species ◽  
Fishing Effort ◽  
Theoretical Concept ◽  
Maximum Sustainable Yield ◽  
Production Model ◽  
The Status ◽  
Long Time

The theory of maximum sustainable yield (MSY) underpins many fishery management regimes and is applied principally as a single species concept. Using a simple dynamic biomass production model we show that MSY can be identified from a long time series of multi-stock data at a regional scale in the presence of species interactions and environmental change. It suggests that MSY is robust and calculable in a multispecies environment, offering a realistic reference point for fishery management. Furthermore, the demonstration of the existence of MSY shows that it is more than a purely theoretical concept. There has been an improvement in the status of stocks in the Northeast Atlantic, but our analysis suggests further reductions in fishing effort would improve long-term yields.

scholarly journals History of earthquake studies in Russia

2009 ◽  
Vol 47 (2-3) ◽  
Author(s):  
R. Tatevossian
Keyword(s):  
Seismic Hazard Assessment ◽  
Historical Seismicity ◽  
Primary Sources ◽  
Original Form ◽  
Correct Identification ◽  
Tectonic Earthquake ◽  
Time Period ◽  
Long Time ◽  
History Of ◽  
Modern Knowledge

To evaluate the completeness of modern knowledge on historical seismicity it is necessary to know the general geopolitical and socio-cultural background in the country. It determines the possibility to record the evidence of an earthquake and conserve the record in original form for a long time-period. The potential duration of historical earthquake study in Russia is assessed based on these considerations. Certain stages of earthquake study in Russia have been detected. Specific problems of seismicity studies of low active areas are discussed as an example of Russian platform. The value of each (even moderate magnitude) event becomes crucial for seismic hazard assessment in such territories. A correct identification of event nature (tectonic earthquake or exogenous phenomena - landslides, karsts, etc.) is practically impossible without using primary sources with detailed descriptions. Occurrence of modern earthquakes can be used to assess the accuracy of historical seismicity knowledge.

scholarly journals Secondary formation of nitrated phenols: insights from observations during the Uintah Basin Winter Ozone Study (UBWOS) 2014

2015 ◽  
Vol 15 (20) ◽  
pp. 28659-28697 ◽  
Author(s):  
B. Yuan ◽  
J. Liggio ◽  
J. Wentzell ◽  
S.-M. Li ◽  
H. Stark ◽  
...  
Keyword(s):  
Gas Phase ◽  
Oil And Gas ◽  
Gas Production ◽  
Heterogeneous Reactions ◽  
Box Model ◽  
Ionization Mass ◽  
Oil And Gas Production ◽  
Production Region ◽  
Secondary Formation ◽  
Online Measurements

Abstract. We describe the results from online measurements of nitrated phenols using a time of flight chemical ionization mass spectrometer (ToF-CIMS) with acetate as reagent ion in an oil and gas production region in January and February of 2014. Strong diurnal profiles were observed for nitrated phenols, with concentration maxima at night. Based on known markers (CH4, NOx, CO2), primary emissions of nitrated phenols were not important in this study. A box model was used to simulate secondary formation of phenol, nitrophenol (NP) and dinitrophenols (DNP). The box model results indicate that oxidation of aromatics in the gas phase can explain the observed concentrations of NP and DNP in this study. Photolysis was the most efficient loss pathway for NP in the gas phase. We show that aqueous-phase reactions and heterogeneous reactions were minor sources of nitrated phenols in our study. This study demonstrates that the emergence of new ToF-CIMS (including PTR-TOF) techniques allows for the measurement of intermediate oxygenates at low levels and these measurements improve our understanding of the evolution of primary VOCs in the atmosphere.

Bondage to the Dead: Poland and the Memory of the Holocaust

2000 ◽  
pp. 444-446
Author(s):  
Michael C. Steinlauf
Keyword(s):  
Primary Sources ◽  
Polish Literature ◽  
The People ◽  
The Holocaust ◽  
The Press ◽  
Polish Society ◽  
Long Time ◽  
Sufficient Distance ◽  
Changing Attitudes ◽  
Second World

(Syracuse, NY: Syracuse University Press, 1997); pp. xiv + 190 + 28 illus. The author of this book is well known among Polish historians. Since 1983 he has visited Poland several times and studied Polish–Jewish relations on site. In his new book he undertakes the difficult task of analysing the changing attitudes of Polish society towards the Holocaust, until 1995. He is probably the best person to write such a book. The Polish and Jewish historians who spent the Second World War in Poland or who are living now in Poland seem the best situated for gathering sources. They are, however, significantly affected by past and contemporary debates over the problems discussed in this book, and it would be difficult for them to free themselves from their own personal experiences. Yet most of the scholars living abroad are too far from the primary sources. Michael Steinlauf, who was born in France, speaks all the necessary languages (Polish and Yiddish, notably), has spent a long time in Poland, and has many Polish friends. He is free from the most significant personal biases and, at the same time, has the necessary knowledge of Polish literature, the press, and the people. He can, therefore, understand the problems and has sufficient distance from Poland and her current hot quarrels to view them with a properly critical eye....

Primary Sources and Secondary Formation of Organic Aerosols in Beijing, China

2012 ◽  
Vol 46 (18) ◽  
pp. 9846-9853 ◽  
Author(s):  
Song Guo ◽  
Min Hu ◽  
Qingfeng Guo ◽  
Xin Zhang ◽  
Mei Zheng ◽  
...  
Keyword(s):  
Organic Aerosols ◽  
Primary Sources ◽  
Secondary Formation ◽  
Beijing China

scholarly journals Observation and Source Apportionment of Trace Gases, Water-Soluble Ions and Carbonaceous Aerosol During a Haze Episode in Wuhan

Atmosphere ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 397 ◽  
Author(s):  
Zhengxu Gao ◽  
Xiaoling Wang ◽  
Lijuan Shen ◽  
Hua Xiang ◽  
Honglei Wang
Keyword(s):  
Organic Carbon ◽  
Air Pollutants ◽  
Principal Component ◽  
Water Soluble ◽  
Vehicle Exhaust ◽  
Soluble Ions ◽  
Secondary Formation ◽  
Water Soluble Ions ◽  
Haze Episode ◽  
Haze Days

As the new core region of the haze pollution, the terrain effect of sub-basin and water networks over the Twin-Hu Basin (THB) in the Yangtze River Middle-Reach (YRMR) had great impacts on the variations and distributions of air pollutants. In this study, trace gases (NH3, HNO3, and HCl), water-soluble ions (WSIs), organic carbon (OC), and elemental carbon (EC) were measured in PM2.5 from 9 January to 27 January 2018, in Wuhan using monitoring for aerosols and gases (MARGA) and a semi-continuous OC/EC analyzer (Model RT-4). The characteristics of air pollutants during a haze episode were discussed, and the PM2.5 sources were quantitatively analyzed on haze and non-haze days using the principal component analysis/absolute principal component scores (PCA/APCS) model. The average PM2.5 concentration was 122.61 μg·m−3 on haze days, which was 2.20 times greater than it was on non-haze days. The concentrations of secondary water soluble ions (WSIs) including NO3−, SO42−, and NH4+ increased sharply on haze days, which accounted for 91.61% of the total WSIs and were 2.43 times larger than the values on non-haze days. The heterogeneous oxidation reactions of NO2 and SO2 during haze episodes were proven to be the major sources of sulfate and nitrate in PM2.5. On haze days, the concentrations of EC, primary organic carbon (POC), and secondary organic carbon (SOC) were 1.68, 1.69, and 1.34 times larger than those on non-haze days, the CO, HNO3, and NH3 concentrations enhanced and relatively low SO2, O3, and HNO2 levels were observed on haze days. The diurnal variations of different pollutants distinctly varied on haze days. The PM2.5 in Wuhan primarily originated from the secondary formation, combustion, dust, industry, and vehicle exhaust sources. The source contributions of the secondary formation + combustion sources to PM2.5 on haze days were 2.79 times larger than the level on non-haze days. The contribution of the vehicle exhaust + combustion source on haze days were 0.59 times the value on non-haze days. This description is supported by a summary of how pollutant concentrations and patterns vary in the THB compared to the variations in other pollution regions in China, which have been more completely described.

scholarly journals Electron-Induced Chemistry in the Condensed Phase

Atoms ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 33
Author(s):  
Jan Hendrik Bredehöft
Keyword(s):  
Gas Phase ◽  
Cross Sections ◽  
Condensed Phase ◽  
Theoretical Understanding ◽  
The Past ◽  
Long Time ◽  
The Difference ◽  
Molecule Interactions ◽  
Multi Body ◽  
Molecule Interaction

Electron–molecule interactions have been studied for a long time. Most of these studies have in the past been limited to the gas phase. In the condensed-phase processes that have recently attracted attention from academia as well as industry, a theoretical understanding is mostly based on electron–molecule interaction data from these gas phase experiments. When transferring this knowledge to condensed-phase problems, where number densities are much higher and multi-body interactions are common, care must be taken to critically interpret data, in the light of this chemical environment. The paper presented here highlights three typical challenges, namely the shift of ionization energies, the difference in absolute cross-sections and branching ratios, and the occurrence of multi-body processes that can stabilize otherwise unstable intermediates. Examples from recent research in astrochemistry, where radiation driven chemistry is imminently important are used to illustrate these challenges.

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