Carbonaceous Particulate Matter Research Articles

Analysis of exhausts emitted by i.c. engines and stationary burners, by means of u.v. extinction and fluorescence spectroscopy

Optical investigations of the exhausts emitted by internal combustion (i.c.) engines and a stationary burner were performed, in order to assess their relative role as sources of organic matter to the atmosphere. Extinction spectra of air-diluted exhausts in the 200–400 nm u.v. band reveal the expected existence of gaseous trace-species (NO, NO 2 and SO 2) and carbonaceous particulate matter (soot). In addition, after subtracting the absorption contribution from known species, a strong residual absorption band remains below 250 nm, which is attributed to organic aromatic matter, involving no more than two aromatic rings. A set of ex situ extinction and laser induced fluorescence (LIF) experiments were carried out on condensed combustion-water samples. Extinction measurements from the water samples show absorption spectra similar to those observed from air-diluted samples, which are attributed to low volatility organic compounds, as they are trapped in the condensed phase. Combining the indications of extinction data for both air-diluted and condensed samples, it is suggested that the absorbing species might be molecular clusters of one/two aromatic rings. LIF spectra from condensed samples evidence two fluorescence bands, centered above 300 and 400 nm, respectively, whose intensities correlate with the combustion regimes. Analogous optical analysis on rain samples, collected in an urban area, showed that rain absorption and fluorescence spectra are similar to those found in condensed exhaust samples, which is consistent with the prevailing contribution of i.c. engines to the urban air pollution. The combined experimental data suggest that the absorbing and fluorescent species trapped in the condensed samples are organic (aromatic) compounds, involving mostly one–two aromatic rings structural units, since they do not absorb above 250 nm. The overall molecular weight of the trapped material is likely heavy as they show low volatility.

Short-Term Inhalation Exposure of Healthy and Compromised Rats and Mice to Fine and Ultrafine Carbon Particles

Epidemiological studies have consistently shown associations between acute pulmonary effects and relatively low levels of ambient particulate matter (PM). The present study was carried out to examine the pulmonary toxicity of inhaled fine (FCB) and ultrafine carbon (UFC) particles as model compounds for carbonaceous (primary) PM, and to identify whether particle size, particle number, and/or mass could be critical in inducing the deleterious effects. Healthy and compromised rats and mice were exposed for 4 h/day during 3 consecutive days to 104 or 105 fine carbon black (~300-500 nm), or 105 or 106 ultrafine carbon (∼30-60 nm) particles/cm3, covering a mass range of about 10 to 10,000 µ/m3. Separate groups of rats were also exposed to a combination of FCB and fine ammonium nitrate at similar number and mass concentrations. Animals were sacrificed the day after the last exposure to determine their pulmonary responses using bronchoalveolar lavage fluid (BALF) analysis and lung histopathology. Exposure to FCB resulted in early signs of lung injury. Effects were not enhanced in compromised animals when compared to healthy animals. Exposure to UFC particles at similar and higher number concentrations did not induce any biologically relevant changes. These data may indicate that at number concentrations occurring in ambient air, the size of the particles (in air) is more important than their number.

Detection of airborne carbonaceous particulate matter by scanning electron microscopy

Airborne particulate matter has been analysed for elemental carbon using a scanning electron microscope equipped with a low atomic number X-ray detector. Problems associated with finding a suitable filter paper for sampling are discussed. Particles were analysed computer control scanning electron microscopy (CCSEM) with the Link program DIGISCAN. Interpretation and classification was performed using multivariate statistical techniques, including MIDAS.

Carbonaceous particles in fly ash -a source for the de-novo-synthesis of organochlorocompounds

In experiments with model mixtures it is demonstrated that the de-novo-synthesis of organohalides from carbonaceous particulate matter and inorganic chloride (activated by copper ions) yields not only PCDD/PCDF but a variety of other compounds such as polychlorobenzenes (Cl 3 to Cl 6), polychloronaphthalenes and -biphenyls. In the presence of bromide also mixed chlorobromospezies are formed.

Organic matter of the troposphere—IV. Lipids in harmattan aerosols of nigeria

Harmattan aerosols were sampled during the 1979 and 1980 seasons in urban, rural and remote areas of Nigeria, in order to characterize sources of the continental carbonaceous particulate matter. High volume air samples (400–3600 m 3) were obtained. The sample filters were extracted and the soluble lipids were separated into functional group fractions for molecular analyses. These lipids were composed primarily of vascular plant wax and minor amounts of microbial detritus, with a significant anthropogenic component from petroleum products and burning superimposed in samples under urban influence. Plant wax was characterized by the homologous series of mainly n-alkanes and n-alkanols, with minor amounts of n-alkanoic acids, n-alkan-2-ones and biomarkers, all in the higher molecular weight range (> C 20). Alcohol fractions contained characteristic phytosterols (C 27–C 29) and triterpenols (C 30 > C 29), which are the biomarkers for vegetation sources. The plant wax signatures of the aerosols in northern Nigeria could be correlated with two dominant geographic source regions (e.g. northern Nigeria and Sahara). A microbial lipid component was evident primarily in the hydrocarbon (as unresolved complex mixture, UCM) and fatty acid fractions (< C 20). Its origin was inferred to be from erosion of lacustrine detritus and from viable microbiota in the ambient particles. Petroleum residues and traces of pyrogenic polynuclear aromatic hydrocarbons (PAH) were present in HC fractions of Harmattan aerosols under some urban influence. These anthropogenic components were comprised of n-alkanes (<C 24, no C number preference), unresolved complex mixture of naphthenic HC ( C max = C 28), minor biomarkers specific for petroleum and traces of PAH. These compositional data were used for very approximate mass balancing and organic matter source determinations. This permitted the assignment of Harmattan aerosol source regions and the conclusion that the urban components are rapidly diluted downwind from their sources by the overwhelming natural organic matter.

Lung Polycyclic Aromatic Hydrocarbon Metabolism during Epithelial Hyperplasia

Human exposures to polycyclic aromatic hydrocarbons, bound to carbonaceous particulate matter, whether it be in urban or occupational environments, or as a result of cigarette smoking, are normally accompanied by inhalation of irritant gases. These air pollutants include the oxides of nitrogen, ozone and acrolein, which not only have been linked to alterations of the lung defense mechanisms responsible for the clearance of particulate matter from the respiratory tract, but also have been associated with pathologic alterations at the epithelial sites identified with the activation and detoxification of polycyclic aromatic hydrocarbons.

Mutagenicity and chemical characteristics of carbonaceous particulate matter from vehicles on the road

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMutagenicity and chemical characteristics of carbonaceous particulate matter from vehicles on the roadWilliam R. Pierson, Robert A. Gorse, Ann Cuneo. Szkarlat, Wanda W. Brachaczek, Steven M. Japar, Frank S. C. Lee, Roy B. Zweidinger, and Larry D. ClaxtonCite this: Environ. Sci. Technol. 1983, 17, 1, 31–44Publication Date (Print):January 1, 1983Publication History Published online1 May 2002Published inissue 1 January 1983https://doi.org/10.1021/es00107a009RIGHTS & PERMISSIONSArticle Views70Altmetric-Citations34LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Get e-Alerts Get e-Alerts

Sampling of carbonaceous particles in the atmosphere

A method for measurement of atmospheric carbonaceous particulate matter is proposed and evaluated. A diffusion denuder, placed ahead of a filter, is used to exclude vapor-phase organic compounds which might be retained by adsorption on the filter. The carbonaceous material lost by volatilization from the filter after collection is retained with a fluidized bed of powdered Al 2O 3. The efficiencies of the denuder and Al 2O 3 were evaluated with vapor phase phenanthrene and octadecane. Atmospheric sampling was done at two urban and one background site in California using the proposed technique in parallel with conventional hi-vol and dichotomous samplers. Hi-vol samples appear to have lost up to half of the particle phase carbon during sampling. About half this error could be eliminated by sampling at low face velocity. The effects of face velocity appear to distort the proportions of fine and coarse particulate carbon obtained with a dichotomous sampler.