Insights into the Origin of Water Soluble Organic Carbon in Atmospheric Fine Particulate Matter

To estimate the oxidative potential (OP) of particulate matter (PM), two commonly used cell-free, molecular probes were applied: dithiothreitol (DTT) and dichloro-dihydro-fluorescein diacetate (DCFH-DA), and their performance was compared with 9,10-bis (phenylethynyl) anthracene-nitroxide (BPEAnit). To the best of our knowledge, this is the first study in which the performance of the DTT and DCFH has been compared with the BPEAnit probe. The average concentrations of PM, organic carbon (OC) and elemental carbon (EC) for fine (PM2.5) and coarse (PM10) particles were determined. The results were 44.8 ± 13.7, 9.8 ± 5.1 and 9.3 ± 4.8 µg·m−3 for PM2.5 and 75.5 ± 25.1, 16.3 ± 8.7 and 11.8 ± 5.3 µg·m−3 for PM10, respectively, for PM, OC and EC. The water-soluble organic carbon (WSOC) fraction accounted for 42 ± 14% and 28 ± 9% of organic carbon in PM2.5 and PM10, respectively. The average volume normalized OP values for the three assays depended on both the sampling periods and the PM fractions. The OPBPEAnit had its peak at 2 p.m.; in the afternoon, it was three times higher compared to the morning and late afternoon values. The DCFH and BPEAnit results were correlated (r = 0.64), while there was no good agreement between the BPEAnit and the DTT (r = 0.14). The total organic content of PM does not necessarily represent oxidative capacity and it shows varying correlation with the OP. With respect to the two PM fractions studied, the OP was mostly associated with smaller particles.

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Effects of Water-soluble Organic Carbon on Aerosol pH

10.5194/acp-2019-344 ◽

2019 ◽

Cited By ~ 1

Author(s):

Michael A. Battaglia Jr. ◽

Rodney J. Weber ◽

Athanasios Nenes ◽

Christopher J. Hennigan

Keyword(s):

Organic Carbon ◽

Fine Particulate Matter ◽

Water Soluble ◽

Organic Species ◽

Aerosol Acidity ◽

Activity Coefficient Model ◽

Water Soluble Organic Carbon ◽

Soluble Organic Carbon ◽

Acidic Conditions ◽

Beijing China

Abstract. Water soluble organic carbon (WSOC) is a ubiquitous and significant fraction of fine particulate matter. Despite advances in aerosol thermodynamic equilibrium models, there is limited understanding on the comprehensive impacts of WSOC on aerosol acidity (pH). We address this limitation by studying submicron aerosol that represent the two extremes in acidity levels found in the atmosphere: strongly acidic aerosol from Baltimore, MD, and weakly acidic conditions characteristic of Beijing, China. These cases are then used to construct mixed inorganic/organic single-phase aqueous particles, and thermodynamically analyzed by the E-AIM and ISORROPIA models (in combination with activity coefficient model AIOMFAC) to evaluate the effects of WSOC on the H+ ion activity coefficients (γH+) and activity (pH). We find that addition of organic acids and non-acid organic species concurrently increases γH+ and aerosol liquid water. When allowed to modulate pH, these effects mostly offset each other, giving pH changes of

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Chemical characterization of fine particulate matter in Changzhou, China, and source apportionment with offline aerosol mass spectrometry

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-2573-2017 ◽

2017 ◽

Vol 17 (4) ◽

pp. 2573-2592 ◽

Cited By ~ 42

Author(s):

Zhaolian Ye ◽

Jiashu Liu ◽

Aijun Gu ◽

Feifei Feng ◽

Yuhai Liu ◽

...

Keyword(s):

Trace Elements ◽

Organic Matter ◽

Particulate Matter ◽

Organic Carbon ◽

Source Apportionment ◽

Fine Particulate Matter ◽

Chemical Characterization ◽

Water Soluble ◽

Aerosol Mass ◽

Fine Particulate

Abstract. Knowledge of aerosol chemistry in densely populated regions is critical for effective reduction of air pollution, while such studies have not been conducted in Changzhou, an important manufacturing base and populated city in the Yangtze River Delta (YRD), China. This work, for the first time, performed a thorough chemical characterization on the fine particulate matter (PM2.5) samples, collected during July 2015 to April 2016 across four seasons in this city. A suite of analytical techniques was employed to measure the organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), water-soluble inorganic ions (WSIIs), trace elements, and polycyclic aromatic hydrocarbons (PAHs) in PM2.5; in particular, an Aerodyne soot particle aerosol mass spectrometer (SP-AMS) was deployed to probe the chemical properties of water-soluble organic aerosol (WSOA). The average PM2.5 concentration was found to be 108.3 µg m−3, and all identified species were able to reconstruct ∼ 80 % of the PM2.5 mass. The WSIIs occupied about half of the PM2.5 mass (∼ 52.1 %), with SO42−, NO3−, and NH4+ as the major ions. On average, nitrate concentrations dominated over sulfate (mass ratio of 1.21), indicating that traffic emissions were more important than stationary sources. OC and EC correlated well with each other and the highest OC ∕ EC ratio (5.16) occurred in winter, suggesting complex OC sources likely including both secondary and primary ones. Concentrations of eight trace elements (Mn, Zn, Al, B, Cr, Cu, Fe, Pb) can contribute up to ∼ 5.0 % of PM2.5 during winter. PAH concentrations were also high in winter (140.25 ng m−3), which were predominated by median/high molecular weight PAHs with five and six rings. The organic matter including both water-soluble and water-insoluble species occupied ∼ 21.5 % of the PM2.5 mass. SP-AMS determined that the WSOA had average atomic oxygen-to-carbon (O ∕ C), hydrogen-to-carbon (H ∕ C), nitrogen-to-carbon (N ∕ C), and organic matter-to-organic carbon (OM ∕ OC) ratios of 0.54, 1.69, 0.11, and 1.99, respectively. Source apportionment of WSOA further identified two secondary OA (SOA) factors (a less oxidized and a more oxidized oxygenated OA) and two primary OA (POA) factors (a nitrogen-enriched hydrocarbon-like traffic OA and a local primary OA likely including species from cooking, coal combustion, etc.). On average, the POA contribution outweighed SOA (55 % vs. 45 %), indicating the important role of local anthropogenic emissions in the aerosol pollution in Changzhou. Our measurement also shows the abundance of organic nitrogen species in WSOA, and the source analyses suggest these species are likely associated with traffic emissions, which warrants more investigations on PM samples from other locations.

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Molecular Speciation of Size Fractionated Particulate Water-Soluble Organic Carbon by Two-Dimensional Nuclear Magnetic Resonance (NMR) Spectroscopy

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18031334 ◽

2021 ◽

Vol 18 (3) ◽

pp. 1334

Author(s):

Marie-Cecile Chalbot ◽

Salma Siddiqui ◽

Ilias G. Kavouras

Keyword(s):

Nuclear Magnetic Resonance ◽

Particle Size ◽

Particulate Matter ◽

Nmr Spectroscopy ◽

Magnetic Resonance ◽

Organic Carbon ◽

Water Soluble ◽

Two Dimensional ◽

Water Soluble Organic Carbon ◽

Soluble Organic Carbon

Particulate matter is associated with increased morbidity and mortality; its effects depend on particle size and chemical content. It is important to understand the composition and resultant toxicological profile of particulate organic compounds, the largest and most complex fraction of particulate matter. The objective of the study was to delineate the nuclear magnetic resonance (NMR) spectral fingerprint of the biologically relevant water-soluble organic carbon (WSOC) fraction of size fractionated urban aerosol. A combination of one and two-dimensional NMR spectroscopy methods was used. The size distribution of particle mass, water-soluble extract, non-exchangeable organic hydrogen functional types and specific biomarkers such as levoglucosan, methane sulfonate, ammonium and saccharides indicated the contribution of fresh and aged wood burning emissions, anthropogenic and biogenic secondary aerosol for fine particles as well as primary traffic exhausts and pollen for large particles. Humic-like macromolecules in the fine particle size range included branched carbon structures containing aromatic, olefinic, keto and nitrile groups and terminal carboxylic and hydroxyl groups such as terpenoid-like polycarboxylic acids and polyols. Our study show that 2D-NMR spectroscopy can be applied to study the chemical composition of size fractionated aerosols.

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Effects of water-soluble organic carbon on aerosol pH

Atmospheric Chemistry and Physics ◽

10.5194/acp-19-14607-2019 ◽

2019 ◽

Vol 19 (23) ◽

pp. 14607-14620 ◽

Cited By ~ 6

Author(s):

Michael A. Battaglia Jr. ◽

Rodney J. Weber ◽

Athanasios Nenes ◽

Christopher J. Hennigan

Keyword(s):

Organic Carbon ◽

Activity Coefficient ◽

Organic Acids ◽

Organic Acid ◽

Fine Particulate Matter ◽

Water Soluble ◽

Ph Changes ◽

Water Soluble Organic Carbon ◽

Soluble Organic Carbon ◽

Acidic Conditions

Abstract. Water-soluble organic carbon (WSOC) is a ubiquitous and significant fraction of fine particulate matter. Despite advances in aerosol thermodynamic equilibrium models, there is limited understanding on the comprehensive impacts of WSOC on aerosol acidity (pH). We address this limitation by studying submicron aerosols that represent the two extremes in acidity levels found in the atmosphere: strongly acidic aerosol from Baltimore, MD, and weakly acidic conditions characteristic of Beijing, China. These cases are then used to construct mixed inorganic–organic single-phase aqueous particles and thermodynamically analyzed by the Extended Aerosol Inorganics Model (E-AIM) and ISORROPIA models in combination with activity coefficient model AIOMFAC (Aerosol Inorganic–Organic Mixtures Functional groups Activity Coefficient) to evaluate the effects of WSOC on the H+ ion activity coefficients (γH+) and activity (pH). We find that addition of organic acids and nonacid organic species concurrently increases γH+ and aerosol liquid water. Under the highly acidic conditions typical of the eastern US (inorganic-only pH ∼1), these effects mostly offset each other, giving pH changes of < 0.5 pH units even at organic aerosol dry mass fractions in excess of 60 %. Under conditions with weaker acidity typical of Beijing (inorganic-only pH ∼4.5), the nonacidic WSOC compounds had similarly minor effects on aerosol pH, but organic acids imparted the largest changes in pH compared to the inorganic-only simulations. Organic acids affect pH in the order of their pKa values (oxalic acid > malonic acid > glutaric acid). Although the inorganic-only pH was above the pKa value of all three organic acids investigated, pH changes in excess of 1 pH unit were only observed at unrealistic organic acid levels (aerosol organic acid concentrations > 35 µg m−3) in Beijing. The model simulations were run at 70 %, 80 %, and 90 % relative humidity (RH) levels and the effect of WSOC was inversely related to RH. At 90 % RH, WSOC altered aerosol pH by up to ∼0.2 pH units, though the effect was up to ∼0.6 pH units at 70 % RH. The somewhat offsetting nature of these effects suggests that aerosol pH is sufficiently constrained by the inorganic constituents alone under conditions where liquid–liquid phase separation is not anticipated to occur.

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Significant Contribution of Primary Sources to Water-Soluble Organic Carbon During Spring in Beijing, China

Atmosphere ◽

10.3390/atmos11040395 ◽

2020 ◽

Vol 11 (4) ◽

pp. 395

Author(s):

Yali Jin ◽

Caiqing Yan ◽

Amy P. Sullivan ◽

Yue Liu ◽

Xinming Wang ◽

...

Keyword(s):

Organic Carbon ◽

Significant Contribution ◽

Fine Particulate Matter ◽

Water Soluble ◽

Primary Sources ◽

Chemical Components ◽

Formation Mechanisms ◽

Secondary Source ◽

Water Soluble Organic Carbon ◽

Soluble Organic Carbon

Despite the significant role water-soluble organic carbon (WSOC) plays in climate and human health, sources and formation mechanisms of atmospheric WSOC are still unclear; especially in some heavily polluted areas. In this study, near real-time WSOC measurement was conducted in Beijing for the first time with a particle-into-liquid-sampler coupled to a total organic carbon analyzer during the springtime, together with collocated online measurements of other chemical components in fine particulate matter with a 1 h time resolution, including elemental carbon (EC), organic carbon (OC), multiple metals, and water-soluble ions. Good correlations of WSOC with primary OC, as well as carbon monoxide, indicated that major sources of WSOC were primary instead of secondary during the study period. The positive matrix factorization model-based source apportionment results quantified that 68 ± 19% of WSOC could be attributed to primary sources, with predominant contributions by biomass burning during the study period. This finding was further confirmed by the estimate with the modified EC-tracer method, suggesting significant contribution of primary sources to WSOC. However, the relative contribution of secondary source to WSOC increased during haze episodes. The WSOC/OC ratio exhibited similar diurnal distributions with O3 and correlated well with secondary WSOC, suggesting that the WSOC/OC ratio might act as an indicator of secondary formation when WSOC was dominated by primary sources. This study provided evidence that primary sources could be major sources of WSOC in some polluted megacities, such as Beijing. From this study, it can be seen that WSOC cannot be simply used as a surrogate of secondary organic aerosol, and its major sources could vary by season and location.

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Effects of Water-soluble Organic Carbon on Aerosol pH

10.5194/egusphere-egu2020-2009 ◽

2020 ◽

Author(s):

Christopher Hennigan ◽

Michael Battaglia, Jr. ◽

Rodney Weber ◽

Athanasios Nenes

Keyword(s):

Organic Carbon ◽

Organic Acids ◽

Organic Acid ◽

Fine Particulate Matter ◽

Dry Mass ◽

Water Soluble ◽

Ph Changes ◽

Water Soluble Organic Carbon ◽

Soluble Organic Carbon ◽

Acidic Conditions

Water soluble organic carbon (WSOC) is a ubiquitous and significant fraction of fine particulate matter.&#160; Despite advances in aerosol thermodynamic equilibrium models, there is limited understanding on the comprehensive impacts of WSOC on aerosol acidity (pH).&#160; We address this limitation by studying submicron aerosol that represent the two extremes in acidity levels found in the atmosphere: strongly acidic aerosol from Baltimore, MD, and weakly acidic conditions characteristic of Beijing, China. These cases are then used to construct mixed inorganic/organic single-phase aqueous particles, and thermodynamically analyzed by the E-AIM and ISORROPIA models in combination with activity coefficient model AIOMFAC to evaluate the effects of WSOC on the H+ ion activity coefficients (&#947;H+) and activity (pH).&#160; We find that addition of organic acids and non-acid organic species concurrently increases &#947;H+ and aerosol liquid water.&#160; Under the highly acidic conditions typical of the eastern U.S. (inorganic-only pH ~1), these effects mostly offset each other, giving pH changes of < 0.5 pH units even at organic aerosol dry mass fractions in excess of 60%.&#160; Under conditions with weaker acidity typical of Beijing (inorganic-only pH ~4.5), the non-acidic WSOC compounds had similarly minor effects on aerosol pH, but organic acids imparted the largest changes in pH compared to the inorganic-only simulations.&#160; Organic acids affect pH in the order of their pKa values (oxalic acid > malonic acid > glutaric acid).&#160; Although the inorganic-only pH was above the pKa value of all three organic acids investigated, pH changes in excess of 1 pH unit were only observed at unrealistic organic acid levels (aerosol organic acid concentrations > 35 &#181;g m-3) in Beijing.&#160; The model simulations were run at 70%, 80%, and 90% relative humidity (RH) levels and the effect of WSOC was inversely related to RH.&#160; At 90% RH, WSOC altered aerosol pH by up to ~0.2 pH units, though the effect was up to ~0.6 pH units at 70% RH.&#160; The somewhat offsetting nature of these effects suggests that aerosol pH is sufficiently constrained by the inorganic constituents alone under conditions where liquid-liquid phase separation is not anticipated to occur.

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Exposure to chemical components of fine particulate matter and ozone, and placenta-mediated pregnancy complications in Tokyo: a register-based study

Journal of Exposure Science & Environmental Epidemiology ◽

10.1038/s41370-021-00299-4 ◽

2021 ◽

Author(s):

Takehiro Michikawa ◽

Seiichi Morokuma ◽

Shin Yamazaki ◽

Akinori Takami ◽

Seiji Sugata ◽

...

Keyword(s):

Particulate Matter ◽

Organic Carbon ◽

Pregnancy Complications ◽

Fine Particulate Matter ◽

First Trimester ◽

Chemical Components ◽

Specific Chemical ◽

Network Database ◽

Fine Particulate ◽

Pollutant Concentrations

Abstract Background Maternal exposure to fine particulate matter (PM2.5) was associated with pregnancy complications. However, we still lack comprehensive evidence regarding which specific chemical components of PM2.5 are more harmful for maternal and foetal health. Objective We focused on exposure over the first trimester (0–13 weeks of gestation), which includes the early placentation period, and investigated whether PM2.5 and its components were associated with placenta-mediated pregnancy complications (combined outcome of small for gestational age, preeclampsia, placental abruption, and stillbirth). Methods From 2013 to 2015, we obtained information, from the Japan Perinatal Registry Network database, on 83,454 women who delivered singleton infants within 23 Tokyo wards (≈627 km2). Using daily filter sampling of PM2.5 at one monitoring location, we analysed carbon and ion components, and assigned the first trimester average of the respective pollutant concentrations to each woman. Results The ORs of placenta-mediated pregnancy complications were 1.14 (95% CI = 1.08–1.22) per 0.51 μg/m3 (interquartile range) increase of organic carbon and 1.11 (1.03–1.18) per 0.06 μg/m3 increase of sodium. Organic carbon was also associated with four individual complications. There was no association between ozone and outcome. Significance There were specific components of PM2.5 that have adverse effects on maternal and foetal health.

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