Oswaldo Massambani

Seasonal behavior of tropospheric ozone in the Sao Paulo (Brazil) metropolitan area

Abstract This paper presents a study of the seasonal behavior of tropospheric ozone and its precursors in the Sao Paulo Metropolitan Area as observed during 1987. The 03, NO, NO 2 , NMHC, and meteorological data were collected at an air quality station in downtown Sao Paulo by the State Environmental Protection Agency (CETESB). The air pollutant measurements were related to both daily total insolation and the number of hours of insolation measured at the Sao Paulo University Climatological Station. Correlations between both radiation parameters and total daily integrated ozone amounts were performed. The total number of sunshine hours was highly correlated to mean hourly ozone concentration values during each month of 1987. The seasonal behavior of NO, NO 2 , and NMHC was also studied. Two diurnal peaks in average NO concentration were observed, i.e. one in early morning and one in early evening; both were due to emissions from urban mobile sources. The magnitude of these peaks doubled in value during the winter months. Its diurnal concentration variation was inverse to that of the 03; similar behavior was found for NO 2 and for NMHC. The data presented herein show the influence of solar radiation and of ozone precursors on photochemical smog formation in this tropical region.

In-cloud and below-cloud numerical simulation of scavenging processes at Serra Do Mar region, SE Brazil

Abstract Atmospheric scavenging processes have been investigated, taking into consideration a numerical simulation through the model Regional Atmospheric Modeling System (RAMS), the below-cloud scavenging model, local atmospheric conditions and local emissions in the Serra do Mar region in southeastern Brazil. The RAMS modeling was coupled with a one-dimensional (1-D) below-cloud scavenging model in order to simulate the in-cloud and below-cloud scavenging processes. RAMS modeling was also used in order to simulate the cloud structures. The aim of the modeling was to predict the average concentration of three chemical species found in rainwater: SO 4 = , NO 3 − and NH 4 + , scavenged from the atmosphere. The concentrations of gases and particles in the samplings, as well as the meteorological parameters obtained during the March 1993 Campaign, were the input data in both models. Another objective was to compare the modeled and the observed rainwater and determine the variability in concentration. Rainwater was obtained by using fractionated rain samplers. Variability was determined through chemical analysis. Urban and rural aerosol spectra modeling were also used in order to compare the rainwater concentration species variability. When both in-cloud and below-cloud processes are included, the general result of the March 1993 events presents a better agreement between modeled and observed data sets than only below-cloud . Preliminary results lead us to conclude that the rainwater variability of nitrate is explained by the scavenging of particles from urban spectrum size distribution, whereas rural spectra explain ammonium rainwater variability—indicating the different sources of those species. Comparing to the March 1992 events, these case studies present a significant contribution from the in-cloud scavenging, supported by the Weather Radar maps and RAMS modeling. In particular, the almost constant rainwater concentrations on 16 March (an indication of strong in-cloud contribution) are related to the rainfall event, which crossed the study area on that day. These results add an important understanding to the atmospheric wet removal processes in the region studied.

Modelling and measurements of below cloud scavenging processes in the highly industrialised region of Cubatão-Brazil

Abstract Below cloud scavenging has been investigated from rainwater chemistry measurements using a one-dimensional scavenging numerical model and surface data from the local atmospheric conditions. The local emissions of pollutants from a large industrial complex in the south-eastern Brazil were also evaluated in the modelling. The scavenging model was coupled to the measurements of SO 2− 4 , NO − 3 and NH + 4 found in the rainwater samples. The concentration of gases and particles samplings and meteorological parameters measured during the study of rain episodes were used as input data in the numerical model, which simulates the raindrop interactions associated with the removal process. The results were compared with those actually measured. The variability of the rainwater concentrations estimated through the scavenging model was also compared to the chemical analysis of the rainwater collected by fractionated rain samplers. The results show a good agreement between both modelled and observed data as seen from the role of the raindrop size distribution in the below cloud scavenging of pollutants

Preliminary Analysis of Atmospheric Scavenging Processes in the Industrial Region of Cubatao, Southeastern Brazil

During a German-Brazilian research project on vegetation damage, atmospheric scavenging processes were investigated, considering transport and local emissions. For this goal, radar precipitation data was evaluated together with analyses of fractionated rain samples of one stratiform and one convective rain event. The temporal variation of pollutant concentration in rain water and the meteorological conditions were compared for both rain events at two stations: one at the top of the Serra do Mar mountain ridge (∼ 900 m) with minor influence of local emissions and one at sea level, close to the high indutrialized area of Cubatao. At the station close to the industrial plants, major influence of the local sources on wet deposition was determined. During the stratiform rain event, an additional influence of transport could be observed. On the top of the Serra do Mar, major influence of the local sources could only be observed during the convective rain event, while transport is mainly responsible for wet deposition during the stratiform event.

Scavenging processes of atmospheric particulate matter: a numerical modeling of case studies

Below cloud scavenging processes have been investigated considering a numerical simulation, local atmospheric conditions and particulate matter (PM) concentrations, at different sites in Germany. The below cloud scavenging model has been coupled with bulk particulate matter counter TSI (Trust Portacounter dataset, consisting of the variability prediction of the particulate air concentrations during chosen rain events. The TSI samples and meteorological parameters were obtained during three winter Campaigns: at Deuselbach, March 1994, consisting in three different events; Sylt, April 1994 and; Freiburg, March 1995. The results show a good agreement between modeled and observed air concentrations, emphasizing the quality of the conceptual model used in the below cloud scavenging numerical modeling. The results between modeled and observed data have also presented high square Pearson coefficient correlations over 0.7 and significant, except the Freiburg Campaign event. The differences between numerical simulations and observed dataset are explained by the wind direction changes and, perhaps, the absence of advection mass terms inside the modeling. These results validate previous works based on the same conceptual model.

BACTERIA AND FUNGAL SPORES AS ICE NUCLEI FROM COFFEA ARABICA L.

Microorganismos tem sido encontrados na atmosfera pela primeira vez no final do seculo XIX century. Alguns destes sao bacterias e especies de fungos com habilidade de atuar como nucleantes de gelo e afetar plantacoes sensiveis a geada como o cafe. Consequentemente, geada e um dos maiores problemas para este tipo de plantacao no Sul-Sudeste do Brasil. Neste estudo, foram encontados tres categorias de organismos com atividade de nucleacao de gelo (INA) em folhas de cafe, tendo por base o ponto de congelamento da solucao salina, cerca de -17oC. A primeira categoria, com forte atividade INA, foi encontrada a Pseudomonas syringae var. garceae, um patogenico de folhas de cafe, como INA+. Pseudomonas syringae var syringae comporta-se com menor efficiencia de INA comparando-a a var. garceae (-5oC contra -4oC). Esta ultima variedade tambem causa a doenca denominada de “mancha aureolada”. A segunda categoria apresentou uma parcial atividade de nucleacao de gelo, incluindo duas outras bacterias: Pantoea agglomerans (conhecida por ter INA+) e Corynebacterium, ambas com pontos de congelamento entre -7oC e -10oC. A terceira categoria apresentou nenhuma atividade nucleadora (INA-), com pontos de congelamento abaixo de -11oC, incluindo-se todas bacterias e fungos. Adicionalmente, H.vastatrix, o fungo responsavel pela ferrugem de cafe, o qual ja causa enormes prejuizos aos agricultores, pode estar associado a bacterias INA+, gerando geada. Estes resultados necessitam melhor averiguamento tentando esclarecer como esta associacao poderia ocorrer. Portanto, duas doencas de plantacoes de cafe, a ferrugem e a mancha aureolada, e a presenca da bacteria Pantoea agglomerans podem estar diretamente e indiretamente associados a atividade de nucleacao de gelo, demandando maior controle biologico, particularmente durante o inverno devido a possibidade de danos por geada.

Uma análise do coeficiente de remoção de poluentes em função do espectro de gotas de chuva em diferentes localidades no Brasil e Alemanha

The pollutant transference among reservoirs atmosphere-hydrosphere, relevant to the atmospheric chemistry, depends upon scavenging coefficient (Λ) calculus, which depends on the raindrop size distribution as well as on the rainfall systems, both different to each locality. In this work, the Λ calculus will be evaluated to gas SO2 and particulate matter fine and coarse among five sites in Germany and two in Brazil. The results show three possible classifications in function of Λ, comparable to literature, however with a greater range due to the differences of rainfall system sites. This preliminary study supports future researches