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Samples of organic aerosol were collected in Santiago de Chile. An activated-charcoal diffusion denuder was used to strip out organic vapors prior to particle collection. Both polynuclear aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons were determined using gas chromatography/mass spectrometry (GC/MS). Organic particle sources were resolved using both concentration diagnostic ratios and multivariate methods such as hierarchical cluster analysis (HCA) and factor analysis (FA). Four factors were identified based on the loadings of PAHs and n-alkanes and were attributed to the following sources: (1) high-temperature combustion of fuels; (2) fugitive emissions from oil residues; (3) biogenic sources; and (4) unburned fuels. Multilinear regression (MLR) analysis was used to determine emission profiles and contributions of the sources. The reconstructed concentrations of particle phase aliphatic and polynuclear aromatic hydrocarbons were in good agreement (R2 > 0.70) with those measured in Santiago de Chile.

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In a Eucalyptus forest in Portugal were investigated (a) the formation of secondary organic aerosol formed through the condensation of low vapor pressure products of monoterpenes (α- and β-pinene) photooxidation and (b) the chemical structure of these products related to their ability to form new particles. Two isomers of pinonic acid (cis- and trans-2,2-dimethyl-3-acetylcyclobutylethanoic acid) and norpinonic acid (cis- and trans-2,2-dimethyl-3-acetylcyclobutylmethanoic acid), pinic acid (cis-2,2-dimethyl-3-carboxycyclobutylethanoic acid), pinonaldehyde (2,2-dimethyl-3-acetylcyclobutylethanal), and nopinone (6,6-dimethylbicyclo[3.1.1]heptan-2-one) were detected in all forest aerosol samples. By considering the diurnal concentration pattern of the acidic products and Aitken nuclei observed during the same periods, our results indicated that cis- and trans-pinonic, cis- and trans- norpinonic and pinic acids are photooxidation products of α-pinene chemically coupled with new particles formed. Lipids such as n-alkanes, n-alkanols, n-alkanals, and n-alkanoic acids determined in the forest aerosol were associated with primary biogenic emissions from Eucalyptus trees.

Transposable elements (TEs) comprise a group of repetitive sequences that bring positive, negative, as well as neutral effects to the host organism. Earlier considered as “junk DNA,” TEs are now well-accepted driving forces of evolution and critical regulators the of expression of genetic information. Their activity is regulated by epigenetic mechanisms, including methylation of DNA and histone modifications. The loss of epigenetic control over TEs, exhibited as loss of DNA methylation and decondensation of the chromatin structure, may result in TEs reactivation, initiation of their insertional mutagenesis (retrotransposition) and has been reported in numerous human diseases, including cancer. Accumulating evidence suggests that these alterations are not the simple consequences of the disease, but often may drive the pathogenesis, as they can be detected early during disease development. Knowledge derived from the in vitro, in vivo, and epidemiological studies, clearly demonstrates that exposure to ubiquitous environmental stressors, many of which are carcinogens or suspected carcinogens, are capable of causing alterations in methylation and expression of TEs and initiate retrotransposition events. Evidence summarized in this review suggests that TEs are the sensitive endpoints for detection of effects caused by such environmental stressors, as ionizing radiation (terrestrial, space, and UV-radiation), air pollution (including particulate matter [PM]-derived and gaseous), persistent organic pollutants, and metals. Furthermore, the significance of these effects is characterized by their early appearance, persistence and presence in both, target organs and peripheral blood. Altogether, these findings suggest that TEs may potentially be introduced into safety and risk assessment and serve as biomarkers of exposure to environmental stressors. Furthermore, TEs also show significant potential to become invaluable surrogate biomarkers in clinic and possible targets for therapeutic modalities for disease treatment and prevention.

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The number of ultrafine particles may be a more health relevant characteristic of ambient particulate matter than the conventionally measured mass. Epidemiological time series studies typically use a central site to characterize human exposure to outdoor air pollution. There is currently very limited information how well measurements at a central site reflect temporal and spatial variation across an urban area for particle number concentrations (PNC). The main objective of the study was to assess the spatial variation of PNC compared to the mass concentration of particles with diameter less than 10 or 2.5 mm (PM 10 and PM 2.5). Continuous measurements of PM 10 , PM 2.5 , PNC and soot concentrations were conducted at a central site during October 2002-March 2004 in four cities spread over Europe (Amsterdam, Athens, Birmingham and Helsinki). The same measurements were conducted directly outside 152 homes spread over the metropolitan areas. Each home was monitored during 1 week. We assessed the temporal correlation and the variability of absolute concentrations. For all particle indices, including particle number, temporal correlation of 24-h average concentrations was high. The median correlation for PNC per city ranged between 0.67 and 0.76. For PM 2.5 median correlation ranged between 0.79 and

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