Simultaneous measurements of outdoor and indoor pollution were performed at three schools in Lisbon. Volatile organic compounds (VOCs), formaldehyde and NO2 were passively monitored over a two-week period. Bacterial and fungal colony-forming units and comfort parameters were also monitored at classrooms and playgrounds. The highest indoor levels of CO2 (2666 μg/m³), NO2 (40.3 μg/m³), VOCs (10.3 μg/m³), formaldehyde (1.03 μg/m³) and bioaerosols (1634 CFU/m³), and some indoor/outdoor ratios greater than unity, suggest that indoor sources and building conditions might have negative effects on air indoors. Increasing ventilation rates and use of low-emission materials would contribute towards improving indoor air quality.

Aerosol size distributions from 6 to 700 nm were measured simultaneously at an urban background site and a roadside station in Oporto. The particle number concentration was higher at the traffic exposed site, where up to 90% of the size spectrum was dominated by the nucleation mode. Larger aerosol mode diameters were observed in the urban background site possibly due to the coagulation processes or uptake of gases during transport. Factor analysis has shown that road traffic and the neighbour stationary sources localised upwind affect the urban area thought intra-regional pollutant transport.

A Berner impactor was used to collect size-differentiated aerosol samples from March to August 2003 in the city of Aveiro, on the Portuguese west coast. The samples were analysed for the main water-soluble ion species. The average concentration of sulphate, nitrate, chloride and ammonium was 6.38, 3.09, 1.67 and 1.27 µg m-3, respectively. The results show that SO4(2-) and NH4+ were consistently present in the fine fraction < 1 µm, which represents, on average, 72 and 89% of their total atmospheric concentrations, respectively. The NO3-particles were concentrated in the coarse size. Chloride presented the characteristic coarse mode for marine aerosols. During some spring/summer events, an ammonium surplus was observed (NH4+/SO4(2-) molar ratios > 2), possibly due to greater availability of ammonia coming from agricultural activities or from the neighbouring chemical industrial complex. During the remaining periods, the aerosol was found to be somewhat acidic and predominantly in the form of ammonium bisulphate (NH4+/SO4(2-) molar ratios = 0.5-1.25). Samples collected under a major or exclusive influence of maritime air masses were essentially constituted by coarse particles with enrichment in sea salt, while for air masses of continental origin the contribution of water-soluble ionic species in the fine mode was more pronounced.

This paper focuses: (i) the development of a measurement technique for the determination of atmospheric C2-C6 hydrocarbons with sampling in canisters and analysis by gas chromatography/flame ionisation detector (GC/FID), (ii) the improvement of an existent adsorption-sampling technique with Tenax TA tubes for the determination of C6-C11 hydrocarbons and analysis by GC/FID after thermal desorption and cryogenic concentration, (iii) the identification of compounds present in ambient air by gas chromatography/mass spectrometry (GC/MS) for both canister and Tenax samples, (iv) a program of interlaboratorial comparison for quality control of C2-C11 analyses, and (v) the seasonal characterisation of ambient air C2-C11 hydrocarbons.

Atendendo às características fotoquímicas atmosféricas, as áreas florestadas dos países mediterrânicos constituem um ambiente apropriado para investigar os aerossóis orgânicos secundários. Este estudo visa estudar in situ a composição dos aerossóis, em particular os produtos resultantes da foto-oxidação de compostos orgânicos voláteis biogênicos, considerando simultaneamente a contribuição antropogênica, e explicar como estes compostos surgem nos aerossóis. As amostragens de matéria particulada atmosférica ocorreram em dois locais: uma floresta de Abies boressi na Grécia central e numa localidade rural próxima da costa, no centro de Portugal. A matéria orgânica presente nos aerossóis foi extraída com solventes e analisada por cromatografia gasosa e espectrometria de massa. Detectaram-se vários produtos resultantes da foto-oxidação de compostos orgânicos voláteis emitidos pela vegetação ou de precursores antropogênicos. Estes constituintes secundários incluem derivados de alcenos, ácidos oxo-, di- e monocarboxílicos, compostos aromáticos oxigenados, aza-arenos, tio-arenos e muitos produtos da foto-oxidação dos terpenos. Esta experiência in situ possibilitou a confirmação da presença de constituintes secundários, os quais haviam sido estudados quase exclusivamente em atmosferas simuladas através de ensaios laboratoriais. Alguns mecanismos reacionais que explicam a formação de compostos na fase particulada a partir de precursores são aqui apresentados.

Taking into account their atmospheric characteristics, generally under photochemical conditions, forested areas of Mediterranean countries constitute an appropriate environment to investigate the secondary organic aerosols. The objective of this study was to study in situ the aerosol composition, particularly in the photo-oxidation products of biogenic volatile organic compounds, taking into consideration anthropogenic inputs, and to explain how these compounds appear in the aerosols. Atmospheric particulate matter was collected at two sites: an Abies boressi forest in central Greece and at Giesta, a coastal-rural site in the centre of Portugal. The collected aerosol was extracted with solvents and characterised by gas chromatography and mass spectrometry. The detected secondary organics include alkene derivatives, oxo-, di- and monocarboxylic acids, oxy-aromatics, aza and thia arenes, and many terpene photo-oxidation products. This in situ experiment allowed confirming the presence of secondary constituents, which have been studied almost exclusively under simulated laboratory conditions. Some reaction pathways leading to the formation of compounds in the particulate phase from precursors are presented.