Characterization of the organic matter in submicron urban aerosols using a Thermo-Desorption Proton-Transfer-Reaction Time-of-Flight Mass Spectrometer (TD-PTR-TOF-MS)

Salvador, Christian Mark; Ho, Tse-Tsung; Chou, Charles C.‐K.; Chen, M.-J.; Huang, Wei; Huang, S.-H.

doi:10.1016/j.atmosenv.2016.06.029

Cited by 18 publications

(26 citation statements)

References 49 publications

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“…The large SOM/SOC ratio suggested that the SOM was composed mostly of molecules with high O/C ratios, dicarboxylic acids and amino acids for instance. This is consistent with the results of a recent study conducted at the TARO station where low-molecular-weight carboxylic acids were found abundant in urban aerosols [Salvador et al, 2016].…”

Section: Instrumentation and Complementary Data Setsupporting

confidence: 93%

Seasonality of the mass concentration and chemical composition of aerosols around an urbanized basin in East Asia

Chou

Hsu²,

Chang

et al. 2017

JGR Atmospheres

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This study investigated seasonal variations in the mass concentration and chemical composition of ambient aerosols observed at three stations (coastal, mountainous, and downtown sites) in northern Taiwan from March 2009 to February 2012. The results show that the major aerosol components include ammonium, sulfate, nitrate, sea salt, dust, organic carbon, and elemental carbon, whereas the mass fraction of each species depends on the sampling location and season. A significant correlation (r = 0.7–0.8) was observed in aerosol concentrations measured at the respective stations, indicating that aerosol concentrations were dominated by regional‐scale factors. Ammonium, sulfate, and nitrate consistently reached respective peak values in the spring in conjunction with dust particle levels. This shows that the transport of dust and particulate air pollutants from the Asian continent has affected the atmospheric environment in this area. Distinct seasonality was observed for sea salt and secondary organic carbon (SOC): sea salt levels peaked in the autumn, whereas SOC levels peaked in the summer, implying that their sources were regulated by independent seasonal factors. Correlation between sea salt concentration and surface wind speed was derived from coastal measurements and showed a high value for the wind speed sensitivity parameter of around 0.37 for our location. In addition, it was revealed that the SOC concentration in aerosols was positively correlated with oxidant photolysis index (Ox × UVB), suggesting that the SOC seasonality was dominated by hydroxyl radical production.

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Section: Instrumentation and Complementary Data Setsupporting

confidence: 93%

Seasonality of the mass concentration and chemical composition of aerosols around an urbanized basin in East Asia

Chou

Hsu²,

Chang

et al. 2017

JGR Atmospheres

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“…The shortcomings of low time resolution with filter measurements can be overcome using this kind of instruments to elucidate more information about the chemical processes involved. Such instrumentations include, for instance, TAG-AMS (thermal desorption aerosol gas chromatograph-AMS) [359][360][361], EESI-TOF-MS (extractive electrospray ionization-time of flight-MS) [362][363][364][365][366], or different inlets associated to PTR-MS (proton-transfer reaction-MS) or CIMS (chemical ionization MS) such as FIGAERO (filter inlet for gases and aerosols) [367], CHARON (chemical analysis of aerosol online) or thermo-desorption (TD) systems [37,[368][369][370][371], which have been successfully applied to apportion SOC in details. However, these instruments are still costly and only appropriate for short term studies.…”

Section: Conclusion and Future Implicationsmentioning

confidence: 99%

Comparison of Measurement-Based Methodologies to Apportion Secondary Organic Carbon (SOC) in PM2.5: A Review of Recent Studies

et al. 2018

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Secondary organic aerosol (SOA) is known to account for a major fraction of airborne particulate matter, with significant impacts on air quality and climate at the global scale. Despite the substantial amount of research studies achieved during these last decades, the source apportionment of the SOA fraction remains difficult due to the complexity of the physicochemical processes involved. The selection and use of appropriate approaches are a major challenge for the atmospheric science community. Several methodologies are nowadays available to perform quantitative and/or predictive assessments of the SOA amount and composition. This review summarizes the current knowledge on the most commonly used approaches to evaluate secondary organic carbon (SOC) contents: elemental carbon (EC) tracer method, chemical mass balance (CMB), SOA tracer method, radiocarbon (14C) measurement and positive matrix factorization (PMF). The principles, limitations, challenges and good practices of each of these methodologies are discussed in the present article. Based on a comprehensive—although not exhaustive—review of research papers published during the last decade (2006–2016), SOC estimates obtained using these methodologies are also summarized for different regions across the world. Conclusions of some studies which are directly comparing the performances of different methodologies are then specifically discussed. An overall picture of SOC contributions and concentrations obtained worldwide for urban sites under similar conditions (i.e., geographical and seasonal ones) is also proposed here. Finally, further needs to improve SOC apportionment methodologies are also identified and discussed.

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“…1 and 3). A clear influence of the aerosol sampling technique on the differences of these parameters can be neither determined nor excluded (Salvador et al, 2016).…”

Section: Charon-ptr-tof-ms Acm-ptr-tof-ms Td-ptr-tof-msmentioning

confidence: 99%

“…However, ACM and TD were operated at 1 bar and up to 250 and 350 • C, respectively, with longer heat exposure times. To further assess whether surface evaporation for ACM and TD had an additional effect on the measurements, focus was placed on the experimental case studies performed by Salvador et al (2016) using the TD-PTR-ToF-MS. Five authentic standard substances (phthalic acid, levoglucosan, arabitol, cis-pinonic and glutaric acid) were utilized to examine the response of the sampling device. If the compounds only fragment in the PTR-ToF-MS due to ionic dissociation, then the detected fragments should have the same volatility trend as the parent compounds since both originate from the latter.…”

Section: Comparison Of Ptr-based Aerosol Measurement Techniques To Smmentioning

confidence: 99%

Comparison of three aerosol chemical characterization techniques utilizing PTR-ToF-MS: a study on freshly formed and aged biogenic SOA

Gkatzelis¹,

Tillmann²,

Hohaus³

et al. 2018

Atmos. Meas. Tech.

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Abstract. An intercomparison of different aerosol chemical characterization techniques has been performed as part of a chamber study of biogenic secondary organic aerosol (BSOA) formation and aging at the atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction chamber). Three different aerosol sampling techniques -the aerosol collection module (ACM), the chemical analysis of aerosol online (CHARON) and the collection thermal-desorption unit (TD) were connected to proton transfer reaction time-of-flight mass spectrometers (PTR-ToF-MSs) to provide chemical characterization of the SOA. The techniques were compared among each other and to results from an aerosol mass spectrometer (AMS) and a scanning mobility particle sizer (SMPS). The experiments investigated SOA formation from the ozonolysis of β-pinene, limonene, a β-pinene-limonene mix and real plant emissions from Pinus sylvestris L. (Scots pine). The SOA was subsequently aged by photo-oxidation, except for limonene SOA, which was aged by NO 3 oxidation. Despite significant differences in the aerosol collection and desorption methods of the PTR-based techniques, the determined chemical composition, i.e. the same major contributing signals, was found by all instruments for the different chemical systems studied. These signals could be attributed to known products expected from the oxidation of the examined monoterpenes. The sampling and desorption method of ACM and TD provided additional information on the volatility of individual compounds and showed relatively good agreement.Averaged over all experiments, the total aerosol mass recovery compared to an SMPS varied within 80 ± 10, 51 ± 5 and 27 ± 3 % for CHARON, ACM and TD, respectively. Comparison to the oxygen-to-carbon ratios (O : C) obtained by AMS showed that all PTR-based techniques observed lower O : C ratios, indicating a loss of molecular oxygen either during aerosol sampling or detection. The differences in total mass recovery and O : C between the three instruments resulted predominantly from differences in the field strength (E/N) in the drift tube reaction ionization chambers of the PTR-ToF-MS instruments and from dissimilarities in the collection/desorption of aerosols. Laboratory case studies showed that PTR-ToF-MS E/N conditions influenced fragmentation which resulted in water and further neutral fragment losses of the detected molecules. Since ACM and TD were operated in higher E/N than CHARON, this resulted in higher fragmentation, thus affecting primarily the detected oxygen and carbon content and therefore also the mass recovery. Overall, these techniques have been shown to provide

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Characterization of the organic matter in submicron urban aerosols using a Thermo-Desorption Proton-Transfer-Reaction Time-of-Flight Mass Spectrometer (TD-PTR-TOF-MS)

Cited by 18 publications

References 49 publications

Seasonality of the mass concentration and chemical composition of aerosols around an urbanized basin in East Asia

Seasonality of the mass concentration and chemical composition of aerosols around an urbanized basin in East Asia

Comparison of Measurement-Based Methodologies to Apportion Secondary Organic Carbon (SOC) in PM2.5: A Review of Recent Studies

Comparison of three aerosol chemical characterization techniques utilizing PTR-ToF-MS: a study on freshly formed and aged biogenic SOA

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