Characterization of atmospheric aerosol and its carbonaceous components at a central Mediterranean site: A multi-method approach using optical, physical, and isotopic techniques

Surface-enhanced Raman spectroscopy (SERS) for the characterization of atmospheric aerosols: Current status and challenges

Chemical characterisation and source identification of atmospheric aerosols in the Snowy Mountains, south-eastern Australia

Characterization of atmospheric aerosols in the Po valley during the supersito campaigns — Part 3: Contribution of wood combustion to wintertime atmospheric aerosols in Emilia Romagna region (Northern Italy)

Multi year sun-photometer measurements for aerosol characterization in a Central Mediterranean site

Molecular characterization of atmospheric organic aerosols: Contemporary applications of high-resolution mass spectrometry

The impact of long-range-transport on PM1 and PM2.5 at a Central Mediterranean site

The unique characteristics of atmospheric aerosol in the northern foot of Mt. Fuji, central Japan were first clarified. The Mt. Fuji (an altitute of 3776 m) is the largest basaltic stratovolcano in the quaternary period in Japan. The aerosol measurements were carried out at an altitute of 1100 m from June 2000 to April 2001. Ambient aerosol in the predominant area of a typical volcanic rock like basalt was referred to as a basaltic aerosol in this study. Fifteen elements (Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Cu, Zn, Ba, Pb) of major to trace in the aerosol samples were determined by X-ray fluorescence spectrometry. Total mass concentration (< 10 μm) of the basaltic aerosol showed the higher values in summer and spring rather than autumn to winter, and the seasonal variation pattern differed widely from that of general urban aerosol. The behavior of the basaltic aerosol was mainly controlled by mineral particles throughout the year, so that a typical anthropogenic-derived element like Pb was very rarely detected. Even V, Cr and Zn which have been generally considered to be typical anthropogenic-derived elements, showed crustal-like behaviors. A concentration ratio of Si/Al showed markedly a uniqueness of the basaltic aerosol. From a comparison with atmospheric aerosol Si/Al ratio in granitic region being an exact opposite geology, a correlation plot of Si/Al ratio against Si concentration was made. It showed a big regional difference available for source identification of atmospheric soil particles. The chemical and geological characteristics of the basaltic aerosol are very useful for the novel characterization of atmospheric soil particles.

The present program can be divided into three main areas of research: chemical characterization of atmospheric aerosols with emphasis on nonphotochemical reactions involving SO/sub 2/, NO, HN/sub 3/, and soot particles; studies of reaction mechanisms; and field studies. The contributions made during the last year in each of these areas are described.

A combination of Raman microscopy and diffuse reflectance Fourier transform infrared spectroscopy (FTIR) has been used for the characterization of fine mode (<1 μm) tropospheric aerosols. Peak fitting was used to identify five overlapping bands in the Raman spectra. These bands have been identified as due to combustion generated carbon soot as well as large molecular organic carbon species. The fwhm of the D band at 1400 cm(-1) as well as the ratio of intensities of the D3 band at 1550 cm(-1) to the G band at 1580 cm(-1) can serve as a measure of the aerosol organic carbon content. Raman microscopy combined with spectral mapping capabilities was used to investigate the composition of the fine mode aerosols at the particle level, allowing for the direct determination of aerosol mixing state. Results showed that the fine aerosols were predominately internally mixed particles composed of carbon soot coated with molecular organic carbon species. Characterization of the aerosols by diffuse reflectance FTIR showed that the major organic carbon species were polycarboxylates and polysaccharide-like species typical of humic-like substances (HULIS).

Atmospheric aerosol characterization with the Dutch–Chinese FAST formation flying mission

The characterisation of atmospheric aerosols is becoming an increasingly important issue for the relevant role played by the aerosols in a variety of physical and chemical processes. In addition, such characterisation is a challenging task for those involved in the development of suitable analytical tools.

In the present paper we report on a sensitive technique for determining anions by means of ion exchange chromatography. The method is suitable for use in the analysis of anion content in atmospheric aerosols. Photometric detection, both direct and indirect is used. Although the direct photometry technique is more sensitive, it does not permit analysis of sulphates. Moreover, indirect photometry does not allow us to measure the levels of bromide in atmospheric aerosols due to its low concentration. These levels are successfully determined by direct photometry. Indirect photometry has the disadvantage that it presents a system peak which may overlap with the peaks of nitrate or sulphate, which do not appear in direct photometry. Nevertheless, if sulphates and bromides need to be analyzed simultaneously, both techniques seem to be complementary. Finally, the possible advantages which this kind of analysis may provide for the understanding and characterization of atmospheric aerosols are also considered.

Characterization of atmospheric aerosols by SEM-EDX in a rural-continental environment-a seasonal approach

Atmospheric aerosol plays a significant role in radiative budget, climate change, hydrological processes, and the global carbon, nitrogen and sulfur cycles. Aerosol optical thickness (AOT) is a key property used in the characterization of atmospheric aerosol. There is a relatively long history of the quantitative estimation of AOT from remotely sensed imagery; especially the dark object method has already made many progresses in the retrieval of AOT over the areas with low surface reflectance. Based on the analysis of the advantages and limits of dark object method, extended dark object method, V5.2 algorithm and four-branched decision method, we introduce a combined method to retrieve AOT over some areas around Beijing using moderate resolution imaging spectroradiometer (MODIS) data, the retrieval results are validated with AERONET data in Beijing and Xianghe sites.

Atmospheric aerosols in the PM10 and PM1 fractions have been sampled at the Global Atmospheric Watch station Mount Cimone, Italy (2165 m above mean sea level) for 3 months during summer 2004, and simultaneous size distributions have been derived by means of an optical particle counter. Samples have been analyzed by X‐ray fluorescence, ion chromatography, and thermal‐optical methodology in order to quantify their elemental, ionic, and carbonaceous constituents. The concentration of PM10 was 16.1 ± 9.8 μg m−3 (average and standard deviation). Source apportionment allowed us to identify, quantify and characterize the following aerosol classes: anthropogenic pollution (10 μg m−3), mineral dust (4 μg m−3), and sea salt (0.2 μg m−3). Pollution has been further split into ammonium sulfate (44%), organic matter (42%), and other compounds (14%). The nitrate/sulfate ratio in the polluted aerosol was 0.1. Fine particles have been completely related to the polluted aerosol component, and they represented 70% in weight of pollution. Coarse particles characterized the dust and salt components, and crustal oxides have been found to be the largest responsible for the aerosol concentration variations that occurred during the campaign. Nitrate has also been found in the coarse particles, representing ∼10% of mineral dust. The analysis of the transport mechanisms responsible for aerosol fluctuations permitted us to identify the origin of the major aerosol components: Pollution has been ascribed to regional transport driven by boundary layer meteorology, whereas mineral dust has been related to long‐range transport events originating in the Sahara and Sahel. A particularly significant Saharan episode has been identified on 10 August 2004 (PM10 daily concentration, 69.9 μg m−3). Average elemental ratios for the African dust events were as follows: Si/Al = 2.31, Fe/Ca = 0.94, Ca/Al = 0.90, K/Ca = 0.44, Ti/Ca = 0.11, and Ti/Fe = 0.12.