Polyfluoroalkyl compounds in the Canadian Arctic atmosphere

Lutz Ahrens; Mahiba Shoeib; Sabino Del Vento; Garry Codling; Crispin Halsall

doi:10.1071/en10131

Polyfluoroalkyl compounds in the Canadian Arctic atmosphere

Environmental Chemistry ◽

10.1071/en10131 ◽

2011 ◽

Vol 8 (4) ◽

pp. 399 ◽

Cited By ~ 46

Author(s):

Lutz Ahrens ◽

Mahiba Shoeib ◽

Sabino Del Vento ◽

Garry Codling ◽

Crispin Halsall

Keyword(s):

Gas Phase ◽

Environmental Concern ◽

Canadian Arctic ◽

High Volume ◽

Ambient Air ◽

Coast Guard ◽

The Arctic ◽

Particle Phase ◽

Method Performance ◽

Arctic Atmosphere

Environmental contextPerfluoroalkyl compounds are of rising environmental concern because of their ubiquitous distribution in remote regions like the Arctic. The present study quantifies these contaminants in the gas and particle phases of the Canadian Arctic atmosphere. The results demonstrate the important role played by gas–particle partitioning in the transport and fate of perfluoroalkyl compounds in the atmosphere. AbstractPolyfluoroalkyl compounds (PFCs) were determined in high-volume air samples during a ship cruise onboard the Canadian Coast Guard Ship Amundsen crossing the Labrador Sea, Hudson Bay and the Beaufort Sea of the Canadian Arctic. Five PFC classes (i.e. perfluoroalkyl carboxylates (PFCAs), polyfluoroalkyl sulfonates (PFSAs), fluorotelomer alcohols (FTOHs), fluorinated sulfonamides (FOSAs), and sulfonamidoethanols (FOSEs)) were analysed separately in the gas phase collected on PUF/XAD-2 sandwiches and in the particle phase on glass-fibre filters (GFFs). The method performance of sampling, extraction and instrumental analysis were compared between two research groups. The FTOHs were the dominant PFCs in the gas phase (20–138 pg m–3), followed by the FOSEs (0.4–23 pg m–3) and FOSAs (0.5–4.7 pg m–3). The PFCAs could only be quantified in the particle phase with low levels (<0.04–0.18 pg m–3). In the particle phase, the dominant PFC class was the FOSEs (0.3–8.6 pg m–3). The particle-associated fraction followed the general trend of: FOSEs (~25 %) > FOSAs (~9 %) > FTOHs (~1 %). Significant positive correlation between ∑FOSA concentrations in the gas phase and ambient air temperature indicate that cold Arctic surfaces, such as the sea-ice snowpack and surface seawater could be influencing FOSAs in the atmosphere.

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Evaluation of atmospheric concentrations of dl-PCBs comparing to PCDD/F compounds in Istanbul, Turkey

Global NEST Journal ◽

10.30955/gnj.002921 ◽

2018 ◽

Vol 21 (2) ◽

pp. 113-123

Keyword(s):

Gas Phase ◽

Meteorological Factors ◽

Winter Season ◽

High Volume ◽

Ambient Air ◽

Particle Phase ◽

Particulate Phase ◽

Air Samples ◽

Atmospheric Concentrations ◽

Homolog Group

In this study, the seasonal variation of atmospheric concentrations of PCDD/F and Dl-PCB and the effect of meteorological factors on concentration were investigated. Ambient air samples were collected monthly between May 2011 and October 2013 by using high volume samplers. Based on these samples, average PCDD/F and dl-PCB concentrations were obtained as 1482 fg/m3 and 4983 fg/m3 respectively. PCDD/F congeners did show seasonal variations. 58% share in total PCDD/Fs belongs to winter season while 4% to summer season. No significant seasonal change has been observed for dl-PCBs. 92% (1397 fg/m3) of PCDD/Fs were detected in particulate phase while 20% (926 fg/m3) of dl-PCBs were found in particulate phase. Strong negative correlations were obtained between all homolog groups and T, UV, SR. Correlation between five-chlorinated dl-PCBs, the most abandoned homolog group, with T, UV and SR generated positive meaningful correlation. No meaningful correlations were observed with other parameters. Correlations with particle phase were found to be more meaningful compared to gas phase for both PCDD/Fs and dl-PCBs.

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Pollution Level and Distribution of PCDD/PCDF Congeners between Gas Phase and Particulate Phase in early Spring Air of Dalian, China

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.71-78.2679 ◽

2011 ◽

Vol 71-78 ◽

pp. 2679-2682

Author(s):

Xiu Hua Zhu ◽

Song Tao Qin ◽

Qian Xu ◽

Yu Wen Ni ◽

Ji Ping Chen ◽

...

Keyword(s):

Gas Phase ◽

Gaseous Phase ◽

High Volume ◽

Ambient Air ◽

Early Spring ◽

Pollution Level ◽

Particulate Phase ◽

Spring Season ◽

International Standard

Ambient air of Dalian was sampled with active high-volume air samplers in early spring time. The concentrations and the congeners between gas phase and particulate phase of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs) in the air were measured. Samples analysis results showed that the concentration of PCDD/Fs in particulate phase was higher than that in gas phase. The ratio of PCDD to PCDF in gaseous phase and particulate phase was lower than 0.4. The main sources of atmospheric PCDD/Fs in Dalian early spring season were coal-related source. The total I-TEQ in gaseous phase and particulate phase was 30.3 and 143.6 fg m-3, respectively. The I-TEQ of Dalian early spring atmosphere was lower than international standard, the atmospheric quality in Dalian was better.

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Observation of HClO3 and HClO4 in the Arctic atmosphere

10.5194/egusphere-egu2020-16908 ◽

2020 ◽

Author(s):

Yee Jun Tham ◽

Nina Sarnela ◽

Carlos A. Cuevas ◽

Iyer Siddharth ◽

Lisa Beck ◽

...

Keyword(s):

Gas Phase ◽

Ozone Depletion ◽

Surface Ozone ◽

Negative Ion ◽

The Arctic ◽

Research Station ◽

Visible Absorption ◽

Data Set ◽

Near Surface ◽

Arctic Atmosphere

Atmospheric halogens chemistry like the catalytic reaction of bromine and chlorine radicals with ozone (O3) has been known to cause the springtime surface-ozone destruction in the polar region. Although the initial atmospheric reactions of chlorine with ozone are well understood, the &#64257;nal oxidation steps leading to the formation of chlorate (ClO3-) and perchlorate (ClO4-) remain unclear due to the lack of direct evidence of their presence and fate in the atmosphere. In this study, we present the first high-resolution ambient data set of gas-phase HClO3 (chloric acid) and HClO4 (perchlorate acid) obtained from the field measurement at the Villum Research Station, Station Nord, in high arctic North Greenland (81&#176;36&#8217; N, 16&#176;40&#8217; W) during the spring of 2015. A state-of-the-art chemical ionization atmospheric pressure interface time-of-flight mass spectrometer (CI-APi-TOF) was used in negative ion mode with nitrate ion as the reagent ion to detect the gas-phase HClO3 and HClO4. We measured significant level of HClO3 and HClO4 only during the springtime ozone depletion events in the Greenland, with concentration up to 9x105 molecule cm-3. Air mass trajectory analysis shows that the air during the ozone depletion event was confined to near-surface, indicating that the O3 and surface of sea-ice/snowpack may play important roles in the formation of HClO3 and HClO4. We used high-level quantum-chemical methods to calculate the ultraviolet-visible absorption spectra and cross-section of HClO3 and HClO4 in the gas-phase to assess their fates in the atmosphere. Overall, our results reveal the presence of HClO3 and HClO4 during ozone depletion events, which could affect the chlorine chemistry in the Arctic atmosphere.

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Mapping gas-phase organic reactivity and concomitant secondary organic aerosol formation: chemometric dimension reduction techniques for the deconvolution of complex atmospheric data sets

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-8077-2015 ◽

2015 ◽

Vol 15 (14) ◽

pp. 8077-8100 ◽

Cited By ~ 7

Author(s):

K. P. Wyche ◽

P. S. Monks ◽

K. L. Smallbone ◽

J. F. Hamilton ◽

M. R. Alfarra ◽

...

Keyword(s):

Phase Composition ◽

Dimension Reduction ◽

Gas Phase ◽

Secondary Organic Aerosol ◽

Ambient Air ◽

Organic Aerosol ◽

Chemical Mechanism ◽

Particle Phase ◽

Aerosol Formation ◽

Holistic View

Abstract. Highly non-linear dynamical systems, such as those found in atmospheric chemistry, necessitate hierarchical approaches to both experiment and modelling in order to ultimately identify and achieve fundamental process-understanding in the full open system. Atmospheric simulation chambers comprise an intermediate in complexity, between a classical laboratory experiment and the full, ambient system. As such, they can generate large volumes of difficult-to-interpret data. Here we describe and implement a chemometric dimension reduction methodology for the deconvolution and interpretation of complex gas- and particle-phase composition spectra. The methodology comprises principal component analysis (PCA), hierarchical cluster analysis (HCA) and positive least-squares discriminant analysis (PLS-DA). These methods are, for the first time, applied to simultaneous gas- and particle-phase composition data obtained from a comprehensive series of environmental simulation chamber experiments focused on biogenic volatile organic compound (BVOC) photooxidation and associated secondary organic aerosol (SOA) formation. We primarily investigated the biogenic SOA precursors isoprene, α-pinene, limonene, myrcene, linalool and β-caryophyllene. The chemometric analysis is used to classify the oxidation systems and resultant SOA according to the controlling chemistry and the products formed. Results show that "model" biogenic oxidative systems can be successfully separated and classified according to their oxidation products. Furthermore, a holistic view of results obtained across both the gas- and particle-phases shows the different SOA formation chemistry, initiating in the gas-phase, proceeding to govern the differences between the various BVOC SOA compositions. The results obtained are used to describe the particle composition in the context of the oxidised gas-phase matrix. An extension of the technique, which incorporates into the statistical models data from anthropogenic (i.e. toluene) oxidation and "more realistic" plant mesocosm systems, demonstrates that such an ensemble of chemometric mapping has the potential to be used for the classification of more complex spectra of unknown origin. More specifically, the addition of mesocosm data from fig and birch tree experiments shows that isoprene and monoterpene emitting sources, respectively, can be mapped onto the statistical model structure and their positional vectors can provide insight into their biological sources and controlling oxidative chemistry. The potential to extend the methodology to the analysis of ambient air is discussed using results obtained from a zero-dimensional box model incorporating mechanistic data obtained from the Master Chemical Mechanism (MCMv3.2). Such an extension to analysing ambient air would prove a powerful asset in assisting with the identification of SOA sources and the elucidation of the underlying chemical mechanisms involved.

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Biogenic, anthropogenic and sea salt sulfate size-segregated aerosols in the Arctic summer

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-5191-2016 ◽

2016 ◽

Vol 16 (8) ◽

pp. 5191-5202 ◽

Cited By ~ 24

Author(s):

Roghayeh Ghahremaninezhad ◽

Ann-Lise Norman ◽

Jonathan P. D. Abbatt ◽

Maurice Levasseur ◽

Jennie L. Thomas

Keyword(s):

Fine Particles ◽

Coast Guard ◽

Sea Salt ◽

The Arctic ◽

Sulfate Concentration ◽

Local Pollution ◽

Fine Aerosol ◽

Two Samples ◽

Range Transport ◽

Arctic Atmosphere

Abstract. Size-segregated aerosol sulfate concentrations were measured on board the Canadian Coast Guard Ship (CCGS) Amundsen in the Arctic during July 2014. The objective of this study was to utilize the isotopic composition of sulfate to address the contribution of anthropogenic and biogenic sources of aerosols to the growth of the different aerosol size fractions in the Arctic atmosphere. Non-sea-salt sulfate is divided into biogenic and anthropogenic sulfate using stable isotope apportionment techniques. A considerable amount of the average sulfate concentration in the fine aerosols with a diameter <  0.49 µm was from biogenic sources (>  63 %), which is higher than in previous Arctic studies measuring above the ocean during fall (<  15 %) (Rempillo et al., 2011) and total aerosol sulfate at higher latitudes at Alert in summer (>  30 %) (Norman et al., 1999). The anthropogenic sulfate concentration was less than that of biogenic sulfate, with potential sources being long-range transport and, more locally, the Amundsen's emissions. Despite attempts to minimize the influence of ship stack emissions, evidence from larger-sized particles demonstrates a contribution from local pollution. A comparison of δ34S values for SO2 and fine aerosols was used to show that gas-to-particle conversion likely occurred during most sampling periods. δ34S values for SO2 and fine aerosols were similar, suggesting the same source for SO2 and aerosol sulfate, except for two samples with a relatively high anthropogenic fraction in particles <  0.49 µm in diameter (15–17 and 17–19 July). The high biogenic fraction of sulfate fine aerosol and similar isotope ratio values of these particles and SO2 emphasize the role of marine organisms (e.g., phytoplankton, algae, bacteria) in the formation of fine particles above the Arctic Ocean during the productive summer months.

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Coupling of organic and inorganic aerosol systems and the effect on gas–particle partitioning in the southeastern US

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-357-2018 ◽

2018 ◽

Vol 18 (1) ◽

pp. 357-370 ◽

Cited By ~ 32

Author(s):

Havala O. T. Pye ◽

Andreas Zuend ◽

Juliane L. Fry ◽

Gabriel Isaacman-VanWertz ◽

Shannon L. Capps ◽

...

Keyword(s):

Gas Phase ◽

Organic Compounds ◽

Thermodynamic Model ◽

Ambient Air ◽

Particle Phase ◽

Organic System ◽

Pure Species ◽

Southeastern Us ◽

Model Predictions ◽

Total Ammonia

Abstract. Several models were used to describe the partitioning of ammonia, water, and organic compounds between the gas and particle phases for conditions in the southeastern US during summer 2013. Existing equilibrium models and frameworks were found to be sufficient, although additional improvements in terms of estimating pure-species vapor pressures are needed. Thermodynamic model predictions were consistent, to first order, with a molar ratio of ammonium to sulfate of approximately 1.6 to 1.8 (ratio of ammonium to 2  ×  sulfate, RN∕2S  ≈  0.8 to 0.9) with approximately 70 % of total ammonia and ammonium (NHx) in the particle. Southeastern Aerosol Research and Characterization Network (SEARCH) gas and aerosol and Southern Oxidant and Aerosol Study (SOAS) Monitor for AeRosols and Gases in Ambient air (MARGA) aerosol measurements were consistent with these conditions. CMAQv5.2 regional chemical transport model predictions did not reflect these conditions due to a factor of 3 overestimate of the nonvolatile cations. In addition, gas-phase ammonia was overestimated in the CMAQ model leading to an even lower fraction of total ammonia in the particle. Chemical Speciation Network (CSN) and aerosol mass spectrometer (AMS) measurements indicated less ammonium per sulfate than SEARCH and MARGA measurements and were inconsistent with thermodynamic model predictions. Organic compounds were predicted to be present to some extent in the same phase as inorganic constituents, modifying their activity and resulting in a decrease in [H+]air (H+ in µg m−3 air), increase in ammonia partitioning to the gas phase, and increase in pH compared to complete organic vs. inorganic liquid–liquid phase separation. In addition, accounting for nonideal mixing modified the pH such that a fully interactive inorganic–organic system had a pH roughly 0.7 units higher than predicted using traditional methods (pH  =  1.5 vs. 0.7). Particle-phase interactions of organic and inorganic compounds were found to increase partitioning towards the particle phase (vs. gas phase) for highly oxygenated (O : C  ≥  0.6) compounds including several isoprene-derived tracers as well as levoglucosan but decrease particle-phase partitioning for low O : C, monoterpene-derived species.

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Fine particle pH and gas-particle partitioning during winter fog in Delhi, India

10.5194/egusphere-egu21-14140 ◽

2021 ◽

Author(s):

Prodip Acharja ◽

Sachin Ghude ◽

Kaushar Ali ◽

Ismail Gultepe

Keyword(s):

Gas Phase ◽

Fine Particle ◽

Chemical Constituents ◽

Fundamental Property ◽

Ambient Air ◽

Water Volume ◽

Winter Period ◽

Particle Phase ◽

Fine Particulates ◽

High Particle

Comprehensive measurements were conducted to simultaneously monitor the trace gases (HCl, HONO, HNO3, SO2, and NH3) and inorganic chemical constituents (Cl-, NO3-, SO42-, Na+, NH4+, K+, Ca2+, and Mg2+) of fine particulates (PM1 and PM2.5) at hourly resolution during the Winter Fog Experiment (WIFEX) field campaign, Delhi, India, for the winter period of 2017-2018. The measurements were performed using the instrument called Monitor for AeRosols and Gases in Ambient air (MARGA-2S) to study the role of chemical composition and gas-particle interplay chemistry in the life cycle of fog, i.e., formation, development, and dissipation phase. In the past, the variation of fine particle acidity (pH) and its impact on fog has not been studied explicitly and quantitatively over Delhi. The pH is a fundamental property of aerosol that plays a significant role in the chemical behavior and composition of particles, but it is very challenging and difficult to measure directly. Particulate water is also a significant component of aerosol and can serve as a medium for aqueous-phase reactions under foggy conditions. The pH depends on the particle water amount, as pH represents the concentration of H+ per liquid water volume (i.e., particulate water). Whereas, H+ concentration per unit volume of air is defined as the particulate proton loading.Using the measured gas-phase and particle-phase concentrations and meteorological observations (T, RH), the particulate water and pH were estimated from the thermodynamic model ISORROPIA-II. In this study, the gas phase NH3, HNO3, and HCl and particle-phase NH4+, NO3-, Cl-, and SO42- species were estimated using ISORROPIA-II, and model predictions of these species were validated by using the measured gas and particle-phase species. The predictions were confirmed by a good agreement between predicted and measured ammonia concentrations (r=0.94) and aerosol species concentrations ammonium (r=0.97) chloride (r=0.61), nitrate (r=0.61), and sulfate (r=0.74). The predicted PM2.5 pH ranged from 2.55 to 6.54, with mean pH of 4.55 &#177; 0.51. This was consistent with the findings of previous studies. It is concluded that high particle water content, higher acidic pH, and abundant ammonia concentrations can promote the gas-particle partitioning and formation of more secondary particles under foggy conditions. The scattering cross-section of these secondary fine hygroscopic particles increases under high humidity conditions due to water uptake, resulting in visibility degradation.

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Strong deviations from thermodynamically expected phase partitioning of organic acids during one year of rural field measurements

10.5194/dach2022-198 ◽

2021 ◽

Author(s):

Andreas Tilgner ◽

Bastian Stieger ◽

Dominik van Pinxteren ◽

Gerald Spindler ◽

Laurent Poulain ◽

...

Keyword(s):

Organic Acids ◽

Gas Phase ◽

Methanesulfonic Acid ◽

Field Measurements ◽

Ambient Air ◽

Water Soluble ◽

Particle Phase ◽

Organic Salts ◽

Phase Partitioning ◽

One Year

Organic acids are ubiquitous compounds in the troposphere and can affect human health, the climate, air quality, and the linked ecosystems. Depending on their solubility and volatility, they can partition in both gas phase and in the particle phase. In the particle phase, organic acids partly represent about 10% of the water-soluble organic matter. However, their partitioning between different phases is not fully understood yet. Therefore, an upgraded monitor for aerosols and gases in ambient air (MARGA) was applied for one year at the Central European TROPOS research site Melpitz to study the gas- and particle-phase partitioning of formic, acetic, propionic, butyric, glycolic, pyruvic, oxalic, malonic, succinic, malic, and methanesulfonic acid (MSA). Measured gas- and PM10 particle-phase mean concentrations were 12&#8722;445 and 7&#8722;31 ng m-3 for monocarboxylic acids (MCAs), between 0.6&#8722;8 and 4&#8722;31 ng m-3 for dicarboxylic acids (DCAs), and 2 and 31 ng m-3 for MSA, respectively. Assuming full dissolution in nonideal aerosol solutions, empirical noneffective Henry&#8217;s law constants (Hemp) were calculated and compared with literature values (Hlit). Calculated mean Hemp were 4.5 &#215; 109&#8722;2.2 &#215; 1010 mol L&#8722;1 atm&#8722;1 for MCAs, 3.6 &#215; 1010&#8722;7.5 &#215; 1011 mol L&#8722;1 atm&#8722;1 for DCAs, and 7.5 &#215; 107 mol L&#8722;1 atm&#8722;1 for MSA and, thus, factors of 5.1 &#215; 103&#8722;9.1 &#215; 105 and 2.5&#8722;20.3 higher than their corresponding Hlit for MCAs and DCAs, respectively, and 9.0 &#215; 10&#8722;5 lower than Hlit,MSA. Data analyses and thermodynamic calculations implicate that the formation of chemical association complexes and organic salts inhibits the partitioning of organic acids toward the gas phase and, thus, at least partly explains higher Hemp&#160;values for both MCAs and summertime DCAs. Low Hemp,MSA are also unexpected because of the high MSA solubility and are reported for the first time in this study. Overall, the results of the present study implicate that processes responsible for the observed stronger partitioning of carboxylic acids toward the particle phase need to be further investigated and accounted for in complex multiphase chemistry models as they affect the contribution of organic acids to secondary organic aerosol mass, their chemical processing, and lifetime. &#160; &#160;

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Characteristics of Atmospheric Polycyclic Aromatic Hydrocarbons (PAHs) in Gas and Particle Phase in April and July 2011 in Beijing, China

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.664.99 ◽

2013 ◽

Vol 664 ◽

pp. 99-105 ◽

Cited By ~ 1

Author(s):

Xiao Liang Cheng ◽

Shao Dong Xie

Keyword(s):

Gas Phase ◽

Aromatic Hydrocarbons ◽

Coal Combustion ◽

Elemental Carbon ◽

Total Concentration ◽

High Volume ◽

Particle Phase ◽

Major Fraction ◽

Polycyclic Aromatic ◽

Beijing China

Presence of atmospheric PAHs in urban and suburban region (Beijing, China) was studied in April and July 2011. Forty-four pairs of gas and particle (TSP) phase samples were collected every six day by high volume (Hi-Vol) air samplers at four sampling sites, and determined separately by GC/MS based on USEPA Method TO-13A. Average total concentration (gas + particles) of PAHs (T-PAHs) was 135.1±49.0 ng/m3 and 181.2±40.9 ng/m3 in April and July, respectively. Gas phase PAHs (G-PAHs) was the major fraction, comprising 63–92% of T-PAHs. Lighter (2-, 3-, 4-ring) and heavier (5-,6-ring) PAHs were found predominantly in gas and particle phase, respectively. 2- to 6- ring PAHs contributed 10%, 53%, 26%, 7% and 4% of T-PAHs, respectively. Five major PAHs, naphthalene (NAP), fluorene (FLU), PHE, fluoranthene (FLA), and pyrene (PYR) contributed 70 – 90% of T-PAHs. G-PAHs increased significantly while PAHs in particle phase (P-PAHs) decreased from April to July. Volatilization from soil and more emission from power generation increase might explain the increase of G-PAHs, and the washout of P-PAHs along with particles might explain the decrease of P-PAHs. Given particulate organic carbon (OC) and elemental carbon (EC) being well correlated, P-PAHs was moderately correlated with OC and EC, suggesting that there were other mechanisms contributing to P-PAHs different from those of OC/EC. Significant correlation between P-PAHs with SO2 and NO2 suggested coal combustion and automobile exhaust to be contamination contributors.

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Biogenic, anthropogenic, and sea salt sulfate size-segregated aerosols in the Arctic summer

10.5194/acp-2015-1010 ◽

2016 ◽

Author(s):

Roghayeh Ghahremaninezhad ◽

Ann-Lise Norman ◽

Jonathan P. D. Abbatt ◽

Maurice Levasseur ◽

Jennie L. Thomas

Keyword(s):

Fine Particles ◽

Coast Guard ◽

Sea Salt ◽

The Arctic ◽

Sulfate Concentration ◽

Local Pollution ◽

Fine Aerosol ◽

Two Samples ◽

Range Transport ◽

Arctic Atmosphere

Abstract. Size-segregated aerosol sulfate concentrations were measured on board the Canadian Coast Guard Ship (CCGS) Amundsen in the Arctic during July 2014. The objective of this study was to utilize the isotopic composition of sulfate to address the contribution of anthropogenic and biogenic sources of aerosols to the growth of the different aerosol size fractions in the Arctic atmosphere. Non-sea salt sulfate is divided into biogenic and anthropogenic sulfate using stable isotope apportionment techniques. A considerable amount of the average sulfate concentration in the fine aerosols with diameter < 0.49 μm was from biogenic sources (> 70 %) which is higher than previous Arctic studies measuring above the ocean during fall (< 15 %) (Rempillo et al., 2011) and total aerosol sulfate at higher latitudes at Alert in summer (> 30 %) (Norman et al., 1999). The anthropogenic sulfate concentration was less than biogenic sulfate, with potential sources being long range transport and, more locally, the Amundsen’s emissions. Despite attempts to minimize the influence of ship stack emissions, evidence from larger-sized particles demonstrates a contribution from local pollution. A comparison of δ34S values for SO2 and fine aerosols was used to show that gas-to-particle conversion likely occurred during most sampling periods. δ34S values for SO2 and fine aerosols were similar suggesting the same source for SO2 and aerosol sulfate, except for two samples with a relatively high anthropogenic fraction in particles < 0.49 μm in diameter (July 15–17 and 17–19). The high biogenic fraction of sulfate fine aerosol and similar isotope ratio values of these particles and SO2 emphasize the role of marine organisims (e.g. phytoplankton, algea, bacteria) in the formation of fine particles above the Arctic Ocean during the productive summer months.

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