Alkanes and polycyclic aromatic hydrocarbons were quantified in samples of coastal sediments along Fildes Peninsula, King George Island, South Shetland Islands, Antarctica, during the summers of 2005 and 2007. Quantification was done by using GC-MS and applying the EPA 3550B method. Individual polycyclic aromatic hydrocarbon (PAHs) concentrations were below 14.4 ng g^-1 dry wt in 2005 and below 88.7 ng g^-1 dry wt in 2007. Alkanes concentrations were higher than those of PAHs and ranged from 8 to 2236 ng g^-1 dry wt in 2005 and from 53 to 745 ng g^-1 dry wt in 2007. Results of total PAHs and alkanes were integrated along with base administrative and geographic maps in a GIS environment to determine the geographic extent of hydrocarbons detected. The largest concentrations were found in areas near research stations where total n-alkanes suggest petrogenic sources and where some diagnostic ratios suggest the presence of some PAHs produced by pyrogenic processes. Even if concentrations of hydrocarbons are low, they seem to be a result of increases in scientific activities, in the activities of the stable population, in the number of tourists, or a combination of theses factors.

Urban trees, air quality and respiratory diseases in six communes of the province of Santiago, Chile Ozone (O 3) is a secondary pollutant, often above the norm in some areas of Santiago in the spring-summer period. It is formed in the atmosphere by photochemical reactions, between nitrogen oxides (NOx) and volatile organic compounds (VOCs), which have an important biogenic contribution (BVOCs). In this research the interrelationship between urban trees, their contribution to atmospheric ozone formation and particulate matter, and respiratory diseases in 6 communes in the province of Santiago was analyzed. The choice of the communes considered the number of inhabitants, the existence of stations monitoring air quality, the percentage of green areas and the geographical distribution. The results showed correlation between the type of species of urban trees, ozone, particulate matter and respiratory diseases: asthma and pneumonia. Necessity for replacement of exotic trees species by native species is concluded.