Influence of Upslope Fog on Hygroscopicity and Chemical Composition of Aerosols at a Forest Site in Taiwan

2020 ◽  
Author(s):  
Chia-Li Chen ◽  
Ting-Yu Chen ◽  
Hui-Ming Hung ◽  
Ping-Wen Tsai ◽  
Wei-Nai Chen ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Carboxylic Acid ◽  
Acid Group ◽  
Forest Site ◽  
Particle Removal ◽  
Carboxylic Acid Group ◽  
Scanning Mobility Particle Sizer ◽  
Aerosol Mass ◽  
Rural Aerosols ◽  
Particle Sizer

<p>This study investigated the influence of upslope fog formation on the chemical composition and single hygroscopicity parameter (κ) of rural aerosols. The compositions were monitored using a mini compact time-of-flight aerosol mass spectrometer (mini-C-ToF-AMS), and a scanning mobility particle sizer (SMPS) from Dec. 1st to Dec. 24th, 2018 at the Xitou forest site (23.40°N, 120.47°E, 1,178 m asl) in Taiwan. Ambient wet aerosol particles were collected by a 13-stage nano-MOUDI II impactor (micro-orifice uniform deposit impactors) and analyzed using a Fourier-transform infrared spectrometer with an attenuated total reflectance accessory (FTIR-ATR). The single hygroscopicity parameter (κ) of aerosols derived from the comparison of AMS pToF size distribution using the κ-Köhler equation and FTIR-ATR measurement. The moderate correlation (r = 0.73) between the oxidized oxygenated organic aerosol (OOA) and CO evidenced the upstream anthropogenic emission transport by sea/land breezes. The decreasing (aerosol mass)/CO ratio with decreasing visibility trends during in-fog periods at two dense foggy events indicated that the fog activation scavenging mechanism dominated the aerosol particle removal. The inconsistency of online real-time AMS and offline FTIR-ATR measurement for submicrometer particles indicated that the evaporation loss of HNO<sub>3</sub> or NH<sub>4</sub>NO<sub>3</sub> particles during MOUDI filter sampling could lead to the unavailable κ retrieval for nitrate-containing particles at non-foggy daytime and the discrepancy of aerosol acidity. Similar κ ranges of organic carboxylic acid group particles (0.1 < κ<sub>p-org</sub> < 0.3), ammonium-containing, and sulfate-containing particles (0.2 < κ<sub>p-NH4 </sub>or κ<sub>p-SO4</sub>< 0.5) but ambiguous nitrate-containing particles (0.4 < κ<sub>p-NO3</sub> < 0.6 or 0.6 < κ<sub>p-NO3 </sub>< 0.8) were observed at foggy daytime, suggesting that ammonium sulfate and organic carboxylic acid compounds were more likely internal mixture particles with similar hygroscopicity and physicochemical mixing state influenced by upslope fog. However, the distinct κ ranges of sulfate-containing particles (0.5 < κ<sub>p-SO4 </sub>< 0.7 or 0.6 < κ<sub>p-SO4 </sub>< 0.8) and organic carboxylic acid group particles (0.1 < κ<sub>p-org</sub> < 0.2) revealed the different chemical and physical properties of external mixture particles at non-foggy daytime.</p><p> </p><p> </p>

scholarly journals Chemical composition, sources, and processes of urban aerosols during summertime in northwest China: insights from high-resolution aerosol mass spectrometry

2014 ◽  
Vol 14 (23) ◽  
pp. 12593-12611 ◽  
Author(s):  
J. Xu ◽  
Q. Zhang ◽  
M. Chen ◽  
X. Ge ◽  
J. Ren ◽  
...  
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Coal Combustion ◽  
Northwest China ◽  
Temporal Variations ◽  
Organic Mass ◽  
Scanning Mobility Particle Sizer ◽  
Aerosol Mass ◽  
Early Afternoon ◽  
Particle Sizer

Abstract. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was deployed along with a scanning mobility particle sizer (SMPS) and a multi-angle absorption photometer (MAAP) to measure the temporal variations of the mass loading, chemical composition, and size distribution of submicron particulate matter (PM1) in Lanzhou, northwest China, during 11 July–7 August 2012. The average (PM1 mass concentration including non-refractory (PM1 (NR-(PM1) measured by HR-ToF-AMS and black carbon (BC) measured by MAAP during this study was 24.5 μg m−3 (ranging from 0.86 to 105 μg m−3), with a mean composition consisting of 47% organics, 16% sulfate, 12% BC, 11% ammonium, 10% nitrate, and 4% chloride. Organic aerosol (OA) on average consisted of 70% carbon, 21% oxygen, 8% hydrogen, and 1% nitrogen, with the average oxygen-to-carbon ratio (O / C) of 0.33 and organic mass-to-carbon ratio (OM / OC) of 1.58. Positive matrix factorization (PMF) of the high-resolution organic mass spectra identified four distinct factors which represent, respectively, two primary OA (POA) emission sources (traffic and food cooking) and two secondary OA (SOA) types – a fresher, semi-volatile oxygenated OA (SV-OOA) and a more aged, low-volatility oxygenated OA (LV-OOA). Traffic-related hydrocarbon-like OA (HOA) and BC displayed distinct diurnal patterns, both with peak at ~ 07:00–11:00 (BJT: UTC +8), corresponding to the morning rush hours, while cooking-emission related OA (COA) peaked during three meal periods. The diurnal profiles of sulfate and LV-OOA displayed a broad peak between ~ 07:00 and 15:00, while those of nitrate, ammonium, and SV-OOA showed a narrower peak between ~ 08:00–13:00. The later morning and early afternoon maximum in the diurnal profiles of secondary aerosol species was likely caused by downward mixing of pollutants aloft, which were likely produced in the residual layer decoupled from the boundary layer during nighttime. The mass spectrum of SV-OOA was similar to that of coal combustion aerosol and likely influenced by coal combustion activities in Lanzhou during summer. The sources of BC were estimated by a linear decomposition algorithm that uses the time series of the NR-PM1 components. Our results indicate that a main source of BC was local traffic (47%) and that transport of regionally processed air masses also contributed significantly to BC observed in Lanzhou. Finally, the concentration and source of polycyclic aromatic hydrocarbons (PAHs) were evaluated.

scholarly journals Chemical composition, sources, and processes of urban aerosols during summertime in Northwest China: insights from High Resolution Aerosol Mass Spectrometry

2014 ◽  
Vol 14 (11) ◽  
pp. 16187-16242 ◽  
Author(s):  
J. Xu ◽  
Q. Zhang ◽  
M. Chen ◽  
X. Ge ◽  
J. Ren ◽  
...  
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Coal Combustion ◽  
Northwest China ◽  
Temporal Variations ◽  
Scanning Mobility Particle Sizer ◽  
Night Time ◽  
Aerosol Mass ◽  
Early Afternoon ◽  
Particle Sizer

Abstract. An aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed along with a Scanning Mobility Particle Sizer (SMPS) and a Multi Angle Absorption Photometers (MAAP) to measure the temporal variations of the mass loading, chemical composition, and size distribution of sub-micrometer particulate matter (PM1) in Lanzhou, northwest China, during 12 July–7 August 2012. The average PM1 mass concentration including non-refractory PM1 (NR-PM1) measured by HR-ToF-AMS and black carbon (BC) measured by MAAP during this study was 24.5 μg m−3 (ranging from 0.86 to 105μg m−3), with a mean composition consisting of 47% organics, 16% sulfate, 12% BC, 11% ammonium, 10% nitrate, and 4% chloride. The organics was consisted of 70% carbon, 21% oxygen, 8% hydrogen, and 1% nitrogen, with the average oxygen-to-carbon ratio (O / C) of 0.33 and organic mass-to-carbon ratio (OM / OC) of 1.58. Positive matrix factorization (PMF) of the high-resolution mass spectra of organic aerosols (OA) identified four distinct factors which represent, respectively, two primary OA (POA) emission sources (traffic and food cooking) and two secondary OA (SOA) types – a fresher, semi-volatile oxygenated OA (SV-OOA) and a more aged, low-volatility oxygenated OA (LV-OOA). Traffic-related hydrocarbon-like OA (HOA) and BC displayed distinct diurnal patterns both with peak at ~07:00–11:00 (BJT: UTC +8) corresponding to the morning rush hours, while cooking OA (COA) peaked during three meal periods. The diurnal profiles of sulfate and LV-OOA displayed a broad peak between ∼07:00–15:00, while those of nitrate, ammonium, and SV-OOA showed a narrower peak at ~08:00–13:00. The later morning and early afternoon peak in the diurnal profiles of secondary aerosol species was likely caused by mixing down of pollutants aloft, which were likely produced in the residual layer decoupled from the boundary layer during night time. The mass spectrum of SV-OOA also showed similarity with that of coal combustion aerosol, likely contributed by coal combustion activities in Lanzhou during summer. The sources of BC were estimated by a linear decomposition algorithm that uses the time series of the NR-PM1 components. Our results indicate that a main source of BC was local traffic (47%) and that transport of regionally processes air masses also contributed significantly to BC observed in Lanzhou. Finally, the concentration and source of polycyclic aromatic hydrocarbons (PAHs) were evaluated.

scholarly journals Insights into the growth of newly formed particles in a subtropical urban environment

2015 ◽  
Vol 15 (23) ◽  
pp. 13475-13485 ◽  
Author(s):  
F. Salimi ◽  
L. R. Crilley ◽  
S. Stevanovic ◽  
Z. Ristovski ◽  
M. Mazaheri ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Quality Parameters ◽  
Scanning Mobility Particle Sizer ◽  
Particle Volume ◽  
Aerosol Mass ◽  
Organic Markers ◽  
Particle Sizer ◽  
Subtropical Environment ◽  
Aerosol Chemical Composition

Abstract. The role of different chemical compounds, particularly organics, involved in the new particle formation (NPF) and its consequent growth are not fully understood. Therefore, this study was conducted to investigate the chemical composition of aerosol particles during NPF events in an urban subtropical environment. Aerosol chemical composition was measured along with particle number size distribution (PNSD) and several other air quality parameters at five sites across an urban subtropical environment. An Aerodyne compact Time-of-Flight Aerosol Mass Spectrometer (c-ToF-AMS) and a TSI Scanning Mobility Particle Sizer (SMPS) measured aerosol chemical composition (particles above 50 nm in vacuum aerodynamic diameter) and PNSD (particles within 9–414 nm in mobility diameter), respectively. Five NPF events, with growth rates in the range 3.3–4.6 nm, were detected at two of the sites. The NPF events happened on relatively warmer days with lower condensation sink (CS). Temporal percent fractions of organics increased after the particles grew enough to have a significant contribution to particle volume, while the mass fraction of ammonium and sulfate decreased. This uncovered the important role of organics in the growth of newly formed particles. Three organic markers, factors f43, f44 and f57, were calculated and the f44 vs. f43 trends were compared between nucleation and non-nucleation days. K-means cluster analysis was performed on f44 vs. f43 data and it was found that they follow different patterns on nucleation days compared to non-nucleation days, whereby f43 decreased for vehicle-emission-generated particles, while both f44 and f43 decreased for NPF-generated particles. It was found for the first time that vehicle-generated and newly formed particles cluster in different locations on f44 vs. f43 plot, and this finding can be potentially used as a tool for source apportionment of measured particles.

The inner salt 4-carboxy-2-(pyridinium-4-yl)-1H-imidazole-5-carboxylate monohydrate

2006 ◽  
Vol 62 (7) ◽  
pp. o2751-o2752 ◽  
Author(s):  
Ting Sun ◽  
Jian-Ping Ma ◽  
Ru-Qi Huang ◽  
Yu-Bin Dong
Keyword(s):  
Carboxylic Acid ◽  
Dihedral Angle ◽  
Title Compound ◽  
Acid Group ◽  
Planar Structure ◽  
Carboxyl Group ◽  
Carboxylic Acid Group ◽  
Pyridyl Group ◽  
Compound C

In the title compound, C10H7N3O4·H2O, one carboxyl group is deprotonated and the pyridyl group is protonated. The inner salt molecule has a planar structure, apart from the carboxylic acid group, which is tilted from the imidazole plane by a small dihedral angle of 7.3 (3)°.

scholarly journals Crystal structure of betulinic acid methanol monosolvate

2014 ◽  
Vol 70 (12) ◽  
pp. o1242-o1243 ◽  
Author(s):  
Wei Tang ◽  
Neng-Hua Chen ◽  
Guo-Qiang Li ◽  
Guo-Cai Wang ◽  
Yao-Lan Li
Keyword(s):  
Carboxylic Acid ◽  
Solvent Molecule ◽  
Acid Group ◽  
Carboxylic Acid Group ◽  
Syzygium Jambos ◽  
Carboxylic Acid Groups ◽  
Pentacyclic Triterpenoid ◽  
Naturally Occurring ◽  
Dimensional Network ◽  
Chinese Medicinal Plant

The title compound [systematic name: 3β-hydroxylup-20(29)-en-28-oic acid methanol monosolvate], C30H48O3·CH3OH, is a solvent pseudopolymorph of a naturally occurring plant-derived lupane-type pentacyclic triterpenoid, which was isolated from the traditional Chinese medicinal plantSyzygium jambos(L.) Alston. The dihedral angle between the planes of the carboxylic acid group and the olefinic group is 12.17 (18)°. TheA/B,B/C,C/DandD/Ering junctions are alltrans-fused. In the crystal, O—H...O hydrogen bonds involving the hydroxy and carboxylic acid groups and the methanol solvent molecule give rise to a two-dimensional network structure lying parallel to (001).

scholarly journals Studies on Adhesion Properties of Grafted EPDM Containing Carboxylic Acid Group

2012 ◽  
Vol 13 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Dongho Kim ◽  
Yoomi Yoon ◽  
Ildoo Chung ◽  
Chanyoung Park ◽  
Jongwoo Bae ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Acid Group ◽  
Carboxylic Acid Group ◽  
Adhesion Properties ◽  
Grafted Epdm

Isolated complexes of the amino acid arginine with polyether and polyamine macrocycles, the role of proton transfer

2017 ◽  
Vol 19 (46) ◽  
pp. 31345-31351 ◽  
Author(s):  
Juan Ramón Avilés-Moreno ◽  
Giel Berden ◽  
Jos Oomens ◽  
Bruno Martínez-Haya
Keyword(s):  
Amino Acid ◽  
Carboxylic Acid ◽  
Proton Transfer ◽  
Acid Group ◽  
Side Group ◽  
Carboxylic Acid Group

Protonated arginine interacts with 12-crown-4 through the guanidinium side group. In the complex with the N-substituted analog cyclen, the dominant conformation is the result of the proton transfer from the carboxylic acid group of the amino acid to the macrocycle.

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