Nazly E. Sánchez

Formation and Characterization of Polyaromatic Hydrocarbons

Issues concerning polycyclic aromatic hydrocarbons (PAH) carcinogenicity, and their important role in formation of dangerous pollutants, such as soot, have motivated their study under a wide range of laboratory conditions and for several kinds of thermochemical processes. Every experimental system, depending on the operating conditions, demands a specific protocol for PAH determination. This chapter aims to contribute to the knowledge of different procedures for PAH quantification both at the gas phase and when they are associated with soot particles. Different kinds of experimental set-ups for PAH formation together with the collection systems to capture them are explained here. Besides, some sample extraction techniques are reviewed, mainly focused on Soxhlet extraction because of its inexpensive equipment and overall simplicity to be applied by staff with limited analytical experience. Chromatographic techniques are also considered, paying special attention to gas chromatography coupled to mass spectrometry (GC–MS), popular in PAH analysis.

Levels of Polycyclic Aromatic Hydrocarbons (PAHs) in Atmospheric Environment of Urban Areas in Latin America

ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) are chemical compounds considered as pollutants of high priority due to their carcinogenic potential. PAH can appear in water, soil or in the atmosphere as adsorbed on particulate material or in gas phase. An increased number of studies on atmospheric PAH in urban areas have been published in the last decade, especially in the last years. Anthropogenic sources are frequently mentioned to be responsible for the increased concentration of PAHs in the atmosphere of urban areas, which at the same time seems to depend on meteorological parameters. This research is focused on compiling information on PAH levels in Latin America and their relationship with typical meteorological variables from seasonal and tropical countries. Brazil is the country with the most number of bibliographies about this topic, followed by Argentina, Chile and Mexico. Scarce information was found for Colombia and Venezuela and none for the rest of Latin American countries. The majority of studies checked have evaluated the climatological parameters in relationship with the PAH concentration and their distribution, finding that it affects meaningfully their levels. The monitor campaigns in Brazil have been developed mainly in the southern cities, where PAHs are strongly influenced by the seasons and their proximity to the South Pole. Tropical countries such as Venezuela and Colombia showed moderate variation of PAH concentration through months. The main influential parameters are precipitation and direction/speed winds.