Organic compounds, in atmospheric aerosol

Hansen, K. J., B. N. Hansen, E. Cravens, and R. E. Sievers, Supercritical Fluid Extraction—Gas Chromatographic Analysis of Organic Compounds in Atmospheric Aerosols, Anal. Chem., 67, 3541-3549 (1995). 

Chan, M. N., Choi, M. Y., Ng, N. L., and Chan, C. K. (2005). Hygroscopicity of water-soluble organic compounds in atmospheric aerosols Amino acids and biomass burning derived organic species. Environ. Sci. Technol. 39,1555-1562. 

Decesari, S., Facchini, M. C., Fuzzi, S., and Tagliavini, E. (2000). Characterization of water-soluble organic compounds in atmospheric aerosols A new approach. 7. Geophys. Res. 105,1481-1489. 

Shimmo, M., A. Piia, K. Hartonem, et al. 2004. Identification of organic compounds in atmospheric aerosol particles by on-line supercritical fluid extraction-liquid chromatography-gas chromatography-mass spectrometry./. Chromatogr. A 1022 151-159. 

Falkovich AH, Rudich Y. 2001. Analysis of semivolatile organic compounds in atmospheric aerosols by direct sample introduction thermal desorption CC/MS. Environ SciTechnol 35 2326-2333. 

Our knowledge of the chemical and physical processes that govern aerosol formation in the atmosphere is limited, and further research in the field is badly needed. Attention should be focused on laboratory studies of aerosol formation from aromatic hydrocarbons. The concentrations of aerosol precursors in the atmosphere should be determined more data on organic compounds in ambient aerosols are needed to estimate the relative importance of olefinic and aromatic hydrocarbons as aerosol precursors. 

Although much emphasis has been placed on characterisation of the organic compounds in atmosphere, recent research suggests that a substantial fraction of both gas-phase and aerosol atmospheric organics have not been, or have very rarely been, determined. A major challenge in atmospheric chemistry research will be to elucidate the sources, structure, transformation and formation processes, and fate of the clearly ubiquitous, yet poorly constrained, organic atmospheric constituents. 

Nowadays, thermo-optical methods are considered the most reliable measurement techniques for OC/EC split in atmospheric aerosols. Nevertheless, methods for TC/EC/BC analysis in atmospheric particles are still open to debate and their different analytical approaches have been the main cause for performing intercomparison studies (Schmid et al., 2001 ten Brink et al., 2004). The TC measurements showed good agreement, whereas the results of EC/BC determinations were highly variable due to EC overestimation by thermal methods. Furthermore, caution must be taken when using BC as an estimative of the EC content in aerosols, and vice versa BC and EC measurements are associated to the carbon content of colored and refractory organic compounds, respectively, which can lead to substantially different results between methods (Poschl, 2005). 

However, not every aerosol particle serves as CCN. Accumulation mode aerosols provide the nuclei for most cloud drops (Penner et al., 2001). As in the case of anthropogenic and natural sulphate particles, OAs can also serve as CCN (Ramanathan et al., 2001). Additionally, the presence of water-soluble organic compounds in the particles and the presence of soluble gases (HN03) in the atmosphere can amplify the CCN activity of the aerosols and further increase the concentration of cloud droplets and the indirect forcing (Charlson et al., 2001). Also, biomass... 

Air quality in homes and workplaces is affected by human activities, construction material, underground minerals, and outside pollution. The most common indoor pollutants are radon, carbon oxides, nitrogen oxides, tobacco smoke, formaldehyde, and a large variety of organic compounds. Indoor atmospheres can also be contaminated with fine particles such as dust, aerosols (from spray cans), fungal spores, and other microorganisms. 

Water-soluble organic compounds in urban atmospheric particles can also contain organosulfur compounds. Methanesulfonic acid and hydroxymethanesulfonic acid have been found as the major organosulfur compounds in urban aerosols, most particularly in particles with the diameter range of 0.43-1.1 p.m. Monomethyl hydrogen sulfate has also been detected on urban particles from localities where no oil or coal power plant exist (Suzuki et al., 2001). 

Particulate emissions are by-products of fuel combustion, industrial processes, and motor vehicles and are believed to have a significant potential for causing adverse health effects. Carbonaceous material present in atmospheric aerosols is a combination of elemental carbon and organic and inorganic compounds. Particulate matter may also consist of fly ash, minerals, or road dust and contain traces of a number of heavy metals. Population-based studies have consistently found that the association between adverse respiratory effects and particulate concentrations occurs in a number of regions throughout the United States. This association is strongest for PM]o and PM2.5 indices (particulate matter less than 10 and 2.5 pm in diameter, respectively). The observed adverse effects include increases in total mortality, mortality due to respiratory and cardiovascular causes, chronic bronchitis, and hospital visits and admissions for asthma. Elderly or unhealthy individuals and infants appear to comprise subpopulations that are most sensitive to the adverse health effects of PM. 

A wide range of structurally diverse compounds is produced during incineration. These include PAHs and related compounds, azaarenes, and chlorinated PAHs from combustion of fossil fuels and natural wildfires. Organic compounds in the atmosphere may exist both in the free (gaseous) state or on particles of various dimensions. Recent concern has been directed to the occurrence in aerosols both of the compounds themselves and of their transformation products (secondary aerosols) (1) for their role in atmospheric chemistry and as determinants of climate (Andreae and Crutzen 1997) and (2) due to health risks since aerosol formation facilitates the transport into and sorption by the lungs. 

Pankow JF (1987) Review and comparative analysis of the theories on partitioning between the gas and aerosol particulate phases in the atmosphere. Atmos Environ 21 2275-2283 (1967) Pankow JF (1994) An absorption model of gas/particle partitioning of organic compounds in the... 

Pankow JF (1994a) An absorption model of gas/aerosol partitioning organic compounds in the atmosphere. Atmos Environ 28 185-188... 

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