This work aims to quantify the wet precipitation the Metropolitan Area of Porto Alegre (MAPA), in southern Brazil, through the analysis of major ions (by ion chromatography) and metallic elements (ICP/AES). By principal components analysis and cluster analysis was possible to identify the influence of natural and anthropic sources in wet precipitation. The results indicated of the higher contribution to the ions NH4+, SO4(2-) and Ca2+. Thus it was possible to identify the contribution of anthropogenic sources in wet precipitation in the study area, such as power plants, oil refineries, steel and vehicle emissions.

Resumo: O Brasil passou por um período de crise energética em 2000. Contudo, este país apresenta vastas reservas de carvão que poderiam ser mais exploradas. Depois da crise o consumo de carvão teve algum incremento, mais estudos deveriam ser feitos a fim de minimizar as emissões de SOx e o aproveitamento das cinzas. As propriedades das cinzas dependem das características dos minerais que as originaram e da temperatura de combustão. A maioria dos sistemas empregados para queima é de combustão em leito pulverizado (1200-1600°C) ou fluidizado (850°C - mais comum fora do Brasil). Este artigo apresenta um estudo preliminar das características físicas do carvão, como tamanho e superfície, submetida a diferentes temperaturas com a finalidade de compreender seu comportamento nestas condições. A reconstrução mineralógica do carvão também foi desenvolvida.

Abstract: Brazil has experienced a small period of power crisis in 2000. However this country has larges resources of coal that could be more explored. Afterwards, coal consumption got some improvement, but studies about its properties should be made to minimize SOx emissions and to develop ashes utilization. The ashes properties are different according to the mineral characteristics and the combustion temperature. Most ordinary coal combustion systems are the pulverized (1200-1600°C) or fluidized (850°C) ones. This paper presents a preliminary study of coal physical characteristics, like particle size and surface, under different temperatures to understand its behavior. Mineralogical reconstruction of coal was also developed.

Este trabalho estabelece uma comparação básica entre dois cenários distintos de simulação da formação de ozônio superficial sobre o Estado do Rio Grande do Sul. No primeiro cenário usa-se um modelo digital de elevação com resolução de 9 km com a interface de simulação "Models-3". No segundo cenário, um modelo com resolução de 3 km é usado. Em cada cenário, implementa-se um único domínio de simulação, com resoluções correspondentes as do respectivo modelo. Dados do Centro Nacional Estadunidense de Previsão Ambiental foram usados na simulação meteorológica, e dados do Instituto Brasileiro de Geografia e Estatística e do Departamento de Trânsito do Rio Grande do Sul foram usados na estimativa das emissões devidas à frota veicular da Região Metropolitana de Porto Alegre (única fonte emissora aqui considerada). Os resultados apresentaram diferenças marcantes entre um cenário e outro. As concentrações constantemente elevadas de ozônio observadas à resolução de 9 km, tiveram seus níveis reduzidos à metade a 3 km. Também os padrões de dispersão tiveram características bem distintas, espalhando-se amplamente sobre a parte sul do domínio de simulação no primeiro cenário e, no segundo, espalhando-se de forma mais limitada sobre a parte sudoeste, com um jato observado em direção noroeste. Elevados níveis de concentração de ozônio foram observados a cerca de 500 km das fontes emissoras.

This study establishes a basic comparison between two different simulation scenarios of surface ozone formation over the Rio Grande do Sul State. In the first simulation scenario, a 9 km resolution digital elevation model is used within the so-called Models-3 simulation interface. In the second one, a 3 km resolution model is used. For each scenario, a single simulation domain was implemented, with resolutions matching the respective model. US National Center for Environmental Prediction's data were used to simulate meteorology, as well as the Brazilian Institute for Geography and Statistics and the Rio Grande do Sul Traffic Department's data were used to estimate emissions by the Metropolitan Area of Porto Alegre vehicle fleet, supposed as the only source of the emissions. The results present striking differences between the two scenarios: the sustained high ozone concentrations values observed at 9 km resolution dropped to half at 3 km resolution. Also, dispersion patterns had quite distinguishable features, spreading widely over the south part of the simulation domain in the first scenario and spreading in a narrower scheme over the south-west region, with a jet observed north-westwards. High levels of ozone concentration were observed as far as 500 km from the emission sources.

The present study aims at assessing the influence of pollution from mobile sources on air quality in the Metropolitan Area of Porto Alegre by means of an inventory based on methods applied specifically to vehicular emissions. The study uses the method described by CETESB, based on inventories on vehicular emissions, according to USEPA methodology. Following fuel types were taken into account: gasoline (24% ethanol), alcohol, diesel oil, and CNG (compressed natural gas). Results have shown that gasoline-powered vehicles are still responsible for emitting the highest CO and HC concentrations, while diesel-powered vehicles are the source of highest NOx, MP and SOx concentrations.

The purpose of the present study is to evaluate the atmospheric behavior in the dispersion of the pollutants SO2, PM10 and NOx emitted by the President Medici power plant in Candiota, RS. The RAMS atmospheric model was applied and the simulations were conducted from april in 20 to 24, 2004. The concentrations of the pollutants simulated by RAMS were compared with the data measured at the air quality monitoring stations. The results showed significant influence of the emissions generated by the power plant on the concentration of the pollutants.

The present work is a preliminary study of total and wet precipitation in the Candiota region, RS. The samples were collected from January to June 2001 at four different sites. The following variables were analysed: pH, conductivity, alkalinity, Cl-, NO3-, F-, SO4(2-), Na+, K+, Mg2+, NH4+, Ca2+ and Zn, Cu, Fe, Al, Mn. The results showed slightly acidic precipitation and higher concentrations of NH4+, Na+, Cl- and SO4(2-). Factor analysis applied to the variables studied allowed identifying the major sources. Na+, Cl- and Mg2+ have their origin in sea salts and NH4+, Ca2+, K+, SO4(2-) and NO3- are from local anthropogenic sources.

The identification and characterization of the hydrochemistry of the groundwaters has been done for seven wells. The sampling occurred during three bimonthly campaigns. The results classified the waters as of the calcium bicarbonated type for the majority of the samples, except for one well, whose composition is of the sodium bicarbonated type. The major ions found and how they determine the quality parameters are consistent with the reactions of mineral dissolution of the majority of volcanic rocks and the reactions with intrusion of alkaline rock in only one well. Anomalous values of nitrate in some wells alert to the impact of especially polluting sources at the time the reservoirs of the hydroeletric plant were formed.

The main purpose of the present work is to study the concentration of atmospheric particles (PM10 and PM2.5) in the Candiota (RS) region using HV PM10 and dichotomous samplers. Four sampling sites at a distance of 50 km from the emission source were selected: Aceguá, Aeroporto, 8 de Agosto and Pedras Altas. Samples were collected from December 2000 to December 2001. The values obtained with the ISCST (Industrial Source Complex Term) model and with the samplers were compared on January 21st, April 5th, July 14th, August 1st, and October 13th 2001, and are representative of frontal systems occurring in the study area.

The present paper has as objective to apply a sequential Cluster Analysis to the atmospheric particles: Hierarchical Cluster Analysis followed by Nonhierarchical Cluster Analysis. The hierarchical cluster analysis results were used as start point for the nonhierarchical cluster analysis as an agglomerative technique. These particles were taken from two areas of the metropolitan region of Porto Alegre, Charqueadas and Sapucaia do Sul., from may /97 to may/98, using a High Volume Sampler (Hi-Vol). Around 10,000 particles were analysed by Scanning Electron Microscope with Energy-Dispersive X-Ray microanalysis (SEM-EDS). The Hierarchical Cluster Analysis allowed the identification of five groups of particles, whose amounts were differentiated according to the summer and the winter campaigns. The abundance of each type of particles inside each group according to the different sections was verified by the Nonhierarchical Cluster Analysis, resulting in information about the emissions sources. The groups of particles of Si/Al and Si and of Fe/Zn and Fe for Charqueadas were more significant in section 2 and 3 (NW and W wind directions) and in section 1 (SE wind direction), evidencing the influence of the coal power plant and steel industry, respectively located in these quadrants. In Sapucaia do Sul the data were more heterogeneous, causing a certain difficulty to identify the source as anthropogenic. Nevertheless the group of particles containing Fe was found in sectors of NW/W wind directions which shows the influence of the steel plant.

This work aims at the study of the air quality determination regarding the total suspended particles (TSP) and the associated metals in the counties of Charqueadas and Sapucaia do Sul at the state of Rio Grande do Sul. The TSP samples were collected using high volume samplers and the analysis of the metallic elements was accomplished through ICP-AES. The results revealed that the TSP concentrations, found in the two studied regions, have exceded the current air quality patterns established by the Brazilian Legislation. They also revealed high levels of several of the elements being attributed to the presence of anthropogenic sources. The correlation between meteorological data (speed and wind direction) and TSP concentrations were significant and revealed strong influence in particle dispersion.