Direct on-strip analysis of size- and time-resolved aerosol impactor samples using laser induced fluorescence spectra excited at 263 and 351 nm

Wang, Chuji; Pan, Yong‐Le; James, D.; Wetmore, Alan; Redding, Brandon

doi:10.1016/j.aca.2014.02.037

Cited by 4 publications

(3 citation statements)

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“…Examples of EEM applications to ambient aerosols can be found in refs − . Time- and wavelength-resolved fluorescence spectra at a fixed excitation wavelength have been recorded for PM samples collected on a drum impactor, resulting in a time resolution of several hours, as well as for single particles − in real time. Thus far, the fixed-wavelength excitation measurements have resulted in an empirical clustering of fluorescence spectra into groups based on the shape of the emission spectra with only tentative correlations between the observed clusters and the molecular identities of the fluorophores. , …”

Section: Overview Of Methods For Physicochemical Characterization Of ...mentioning

confidence: 99%

Chemistry of Atmospheric Brown Carbon

Laskin¹,

Laskin²,

2015

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Section: Overview Of Methods For Physicochemical Characterization Of ...mentioning

confidence: 99%

Chemistry of Atmospheric Brown Carbon

Laskin¹,

Laskin²,

2015

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“…Examples of EEM applications to ambient aerosols can be found in refs 240−243. Time-and wavelength-resolved fluorescence spectra at a fixed excitation wavelength have been recorded for PM samples collected on a drum impactor, 244 resulting in a time resolution of several hours, as well as for single particles 245−247 in real time. Thus far, the fixed-wavelength excitation measurements have resulted in an empirical clustering of fluorescence spectra into groups based on the shape of the emission spectra with only tentative correlations between the observed clusters and the molecular identities of the fluorophores.…”

Section: Eem Fluorescence Experimentsmentioning

confidence: 99%

Chemistry of Atmospheric Brown Carbon

Laskin¹

2020

Preprint

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<p>Fundamental understanding of the complex chemistry of light absorbing atmospheric aerosols (aka Brown Carbon - BrC), their physico-chemical properties and environmental impacts is a challenging task because no single method of analytical chemistry is capable of providing the full range of analytical chemistry information. Micro-spectroscopy approaches can visualize individual particles and their internal structures; however, they largely exclude molecular-level information, and are limited to elemental and chemical bonding characterization. Contemporary methods of high-resolution mass spectrometry can provide detailed information on the molecular content of BrC, but these methods use bulk particle samples and provide no knowledge of the individual particle composition. Therefore, application of complementary analytical methods of chemical analysis is necessary for comprehensive characterization of aerosol properties ranging from bulk molecular composition of BrC constituents to microscopy level details of individual particles. Combined assessment of the results provided by complementary analytical chemistry techniques offers unique insights to understand the composition and physico-chemical properties of BrC aerosols determining their effects on air quality and climate. This presentation will give an overview of recent field and laboratory studies of BrC with an overall goal to understand fundamental relationship between chemical transformations of airborne particles and their environmental and climate impacts.</p>

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“…Such samplers provide size-segregated aerosol samples collected with high temporal resolution on rotating thin foils. Aerosol deposits are usually characterised for elemental concentration (Na-Pb) using different non-destructive techniques such as Particle-Induced X-Ray emission (Annegarn, 1987;Cahill, 1996;Calzolai et al, 2015), Energy-Dispersive X-Ray Fluorescence (Giannoni et al, 2015), Syncrotron Radiation X-Ray Fluorescence (Bukowiecki et al, 2005) or for organic/biological components (Wang et al, 2014). High-time resolved source apportionment studies have been performed typically using elemental composition (e.g.…”

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confidence: 99%

Set-up of a multi wavelength polar photometer for off-line absorption coefficient measurements on 1-h resolved aerosol samples

Bernardoni

Valli

Vecchi

2017

Journal of Aerosol Science

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In this paper, a polar photometer (PP_UniMI) was set up to measure the aerosol absorption coefficient (σ ap) at four wavelengths (λ) on 1-h resolved aerosol samples collected using a streaker sampler. Due to the characteristics of such samples (small deposit area, low aerosol load, and limited substrate thickness-10μm), the main technical developments aimed at reaching suitable limits of detection (LODs). To this aim, multiple scattering between the sample and a suitable substrate were exploited to amplify the system sensitivity to absorbing particle load. In the paper, the development and test of this innovative approach is presented. LODs for σ ap in the range 5.0-11.6 Mm-1 were reached, depending on the wavelength. Such values were suitable for the analysis of 1-hour resolved samples collected at an urban background site in Milan (Italy) during a test campaign of 1-week carried out in winter 2015. The methodology was validated comparing σ ap measurements performed by PP_UniMI at λ=635nm on the streaker sample to the data obtained by a Multi-Angle Absorption Photometer (MAAP) operated in parallel. Agreement within 10% was found. To check the results obtained at other wavelengths, Ångström Absorption Exponent (AAE) was calculated from σ ap measurements at 4-λ. The AAE values resulted in the range of expectations for aerosol emitted by fossil fuel combustion (0.8-1.2) and wood burning (0.9-3.5), which are the main sources contributing to absorbing aerosol in urban areas in winter. 2 The analytical methodology can be extended to samples collected with high time resolution using other high-time resolution samplers (e.g. drum rotating impactors). This is-as far as we know-the first time that σ ap measurements are performed on streaker samples collected with 1-h resolution. Our results thus set PP_UniMI as an important tool for the community performing high time resolved sampling to widen the characterisation of such samples and to further develop source apportionment studies.

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Direct on-strip analysis of size- and time-resolved aerosol impactor samples using laser induced fluorescence spectra excited at 263 and 351 nm

Cited by 4 publications

References 34 publications

Chemistry of Atmospheric Brown Carbon

Chemistry of Atmospheric Brown Carbon

Chemistry of Atmospheric Brown Carbon

Set-up of a multi wavelength polar photometer for off-line absorption coefficient measurements on 1-h resolved aerosol samples

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