Metropolitan Area Of Sao Paulo Research Articles

Relation between ozone levels and NOx and VOC emissions in the Sao Paulo Metropolitan Area for an episode of August, 1998

At present, major efforts in air pollution control for urban areas are oriented to reduce ozone levels to below standards. Models are a useful tool for air quality assessment and they can help to select the best strategy plan to reduce ozone levels in a polluted area. Like other large cities in the world, Sao Paulo Metropolitan Area (SPMA) has registered high levels of ozone and particulate matter for several decades. In order to establish appropriate strategy plans, a photochemical model has been used for an episode that occurred in 1999. Simple emission control strategies have been examined.

Planejamento e aspectos ambientais envolvidos na disposição final de lodos das estações de tratamento de água da Região Metropolitana de São Paulo

A disposição de lodos de estações de tratamento de água (ETAs) de forma ambientalmente correta configura-se em mais um desafio a ser enfrentado pelas companhias de saneamento e tem recebido maior atenção no Brasil e na Região Metropolitana de São Paulo (RMSP) nos últimos anos. O objetivo deste trabalho foi apresentar alternativas existentes de uso e disposição final dos lodos das ETAs da RMSP e, assim sendo, foram pesquisadas várias técnicas de uso e disposição de lodos praticados no Brasil e no mundo e suas condições técnicas e ambientais. Foram avaliadas a quantidade de lodos gerados na RMSP e a existência ou previsão de implantação de sistemas de adensamento e desidratação e, a partir destas informações, foram identificadas alternativas de uso e disposição tecnicamente e ambientalmente exeqüíveis para os lodos das ETAs da RMSP.

In-cloud and below-cloud scavenging analysis of sulfate in the metropolitan area of São Paulo, Brasil

The Metropolitan Area of São Paulo (MASP) is one of the largest urban centers in the world. The significant atmospheric concentrations of ozone, inhalable particles and other pollutants in the MASP raise serious air-quality concerns. In this study, we consider gases, particulate matter (PM) and cloud processes, with a focus on sulfate chemistry. The Regional Atmospheric Modeling System mesoscale numerical model was used in conjunction with detailed scavenging models to compare varying PM mass spectra and size distributions. Field data were collected during the July 1989-May 1990 and February-October 2000 campaigns. Adjusted-urban and rural spectra seem to fit better with observed results which improved the scavenging numerical modeling. Correlations between modeled and observed concentrations were better when the model included rural and adjusted-urban spectra, suggesting locally dominant below-cloud scavenging. Spatial variability analysis and numerical modeling also revealed that the varying sulfate rainwater concentrations indicate below-cloud removal process dominance.

The impact on tropospheric ozone formation on the implementation of a program for mobile emissions control: a case study in São Paulo, Brazil

The main sources of reactive hydrocarbons (RHC) and nitrogen oxides (NOx), ozone precursors, in the Metropolitan Area of Sao Paulo (MASP) in the southeast of Brazil are emissions from vehicles fleets. Ambient surface ozone and particulate matter concentrations are air quality problem in the MASP. This study examined the impact that implementing a control program for mobile emissions has on ozone concentrations, An episode of high surface ozone concentrations occurring in the MASP during the March 13–15, 2000 period was used as a case study that was modeled for photochemical oxidants using the California Institute of Technology/Carnegie Mellon University three-dimensional photochemical model. Different scenarios were analyzed in relationship to the implementation of the Programa Nacional de Controle de Poluicao por Veiculos Automotores (PROCONVE, National Program to Control Motor Vehicle Pollution). Scenario 1 assumed that all vehicles were operating within PROCONVE guidelines. Scenarios 2 and 3 considered hypothetical situations in which the PROCONVE was not implemented. Scenario 2 set the premise that vehicles were using pre-1989 technology, whereas scenario 3 allowed for technological advances. A base case scenario, in which the official emission inventory for the year 2000 was employed, was also analyzed. The CIT model results show agreement with most measurements collected during 13–15 March 2000 modeling episode. Mean normalized bias for ozone, CO, RHC and NO x are approximately 9.0, 6.0, −8.3, 13.0%, respectively. Tropospheric ozone concentrations predicted for scenario 2 were higher than those predicted for scenarios 1, 3 and base case. This study makes a significant contribution to the evaluation of air quality improvement and provides data for use in evaluating the economic costs of implementing a program of motor vehicle pollution control aimed at protecting human health.

Emission Factors for Gas-Powered Vehicles Traveling Through Road Tunnels in São Paulo, Brazil

The objective of this study was to improve the vehicular emissions inventory for the light- and heavy-duty fleet in the metropolitan area of São Paulo (MASP), Brazil. To that end, we measured vehicle emissions in road tunnels located in the MASP. On March 22-26, 2004 and May 04-07, 2004, respectively, CO, CO2, NOx, SO2, and volatile organic compounds (VOCs) emissions were measured in two tunnels: the Janio Quadros, which carries light-dutyvehicles; and the Maria Maluf, which carries light-duty vehicles and heavy-duty diesel trucks. Pollutant concentrations were measured inside the tunnels, and background pollutant concentrations were measured outside of the tunnels. The mean CO and NOx emission factors (in g km(-1)) were, respectively, 14.6 +/- 2.3 and 1.6 +/- 0.3 for light-duty vehicles, compared with 20.6 +/- 4.7 and 22.3 +/- 9.8 for heavy-duty vehicles. The total VOCs emission factor for the Maria Maluf tunnel was 1.4 +/- 1.3 g km(-1). The main VOCs classes identified were aromatic, alkane, and aldehyde compounds. For the heavy-duty fleet, NOx emission factors were approximately 14 times higher than those found for the light-duty fleet. This was attributed to the high levels of NOx emissions from diesel vehicles.

Wet deposition and related atmospheric chemistry in the São Paulo metropolis, Brazil. Part 3: Trends in precipitation chemistry during 1983–2003

The metropolitan area of São Paulo (MASP), with 18 million inhabitants, is one of the largest urban areas of the world, with serious environmental problems, including atmospheric pollution. Even though there is an official network monitoring the air quality, it does not include data on the chemical composition of precipitation. However, some research groups have sampled and measured common analytes in rainwater on several sites at MASP during restricted periods. Eventually, available data of pH values and ion concentrations in rainwater since 1983 in the city of São Paulo have been compiled and are, now, discussed in this work, which, besides showing possible trends, gives support for future studies planned in MASP. A decreasing trend of rainwater free acidity in São Paulo occurred along the 2 decades considered. Since 1995, no monthly volume weight mean (VWM m) pH values below 4.5 have been observed which, in part, reflects the gradual decrease in the atmospheric concentrations of the SO 2, with annual average of 65 μg m −3 in 1983 and 15 μg m −3 in 2003. Scarce data on sulfate concentration in the rain shows a similar decay from 33±35 μmol L −1 in 1989–1990 to 19±18 μmol L −1 in 2002–2003. Despite the fact that no significant trends can be inferred in the limited nitrate database, for ammonium, high concentrations (47±42 μmol L −1 of NH 4 +) have been observed in recent years, indicating the contribution of the NH 3 present in the São Paulo's atmosphere to the neutralization of the rain acidity.

Morphology and Solutes Content of Atmospheric Particles in an Urban and a Natural Area of São Paulo State, Brazil

The objectives of this work were to characterize and compare the chemical composition of the water-soluble fraction of the PM10 particles (Dp < 10μm) in two sites: one inside the Metropolitan Area of Sao Paulo (MASP) and another, 250km apart, inside the State Park of Serra do Mar (CUNHA) part of the Atlantic Forest Reserve, both located in Sao Paulo State, Brazil. The atmospheric particles were collected during dry and wet season. The morphologic parameters of the particles were characterized for the different size fractions of the collected material. In the aqueous extract of the particulate fine fraction the major ions (Na+, K+, Mg2+, Ca2+, Cl−, NO3−, NH4+, SO42−) and trace elements (Al, Mn, Fe, Pb, Cd, Zn, Ti, Ni, Cu, Co, Ba) were determined. The morphological characteristics of the particles collected within the MASP are typical of polluted environment while in CUNHA there is no evidence of this type of contribution. Regarding the solute concentrations it was observed that the most abundant major ions and trace elements were K+, Ca2+, Na+, Cl− and Pb, for CUNHA and NO3−, SO42−, NH4+ and Mn, Ni, Pb, Co, Cd and Ba for MASP. These differences are associated with the different sources of the particles. In the urban area they are predominantly of pollution origin, mainly from vehicle emissions, and road dust suspension, while in the State Park they are mainly of biogenic, terrigenous and oceanic origins. For these reasons the CUNHA region can be considered to be a regional reference site for studies concerning eventual disturbances in the Cunha background site, derived from transported pollution.

Impacts of ozone precursor limitation and meteorological variables on ozone concentration in São Paulo, Brazil

Ozone concentrations in the heavily polluted metropolitan area of São Paulo (MASP), in Brazil, frequently exceed established international standards. This study aims to describe the impact that three meteorological variables (mixing height, wind speed and air temperature) on the ozone concentration, as well as reactive hydrocarbon (RHC) limitation and nitrogen oxide (NO x ) limitation, have on ozone formation in the area. To achieve these objectives the California Institute of Technology (CIT) Eulerian air quality model was applied combined with the same methodology described in Baertsch-Ritter et al. [2004. Atmospheric Chemistry and Physics 4, 423–438] In addition, NO x and RHC emission inventory reductions were used to evaluate their sensitivities in the CIT model. A simulation of an episode occurring in the MASP on 22 August 2000, when a peak ozone level of 127 ppbv was recorded, is presented. In the CIT model results for the base case, primary pollutant concentrations and ozone concentrations are in good agreement with the measured data. In addition, changes in mixing height, wind speed and air temperature input files have the greatest effect on peak ozone in the MASP, and the isolated effect of RHC emission inventory reduction leads to 26% lower ozone levels than in the base case. Based on the results of this study, we can conclude that with reduction of RHC emission could provide the best scenario for promoting lower ozone concentrations in the MASP.

A distribuição espacial dos termos do balanço de energia em superfície a partir de imagem orbital e observação de campo

Estimates of the balance energy in surface is performed over the Metropolitan Area of São Paulo (MASP). A modified method based on the procedure used by Lopes (2003), in the case of the Metropolitan Area of Lisboa (MAL) – Portugal, and a similar classification of land cover suggested by Sukopp et al. (1979), related to the Metropolitan Area of Western Berlin (MAWB) – Germany, are employed . Data sets obtained from sensors installed in orbital platforms and mobile platforms at the surface are combined and used in order to elaborate the analysis. The generated balance shows a pattern that is not analogous to the traditional one only generated from orbital data sets. Observations raised up into the urban canopy layer give us a new sense that comprises the meaning of the energy balance from a pedestrian perspective.

Determination of O3-, CO- and PM10-transport in the metropolitan area of São Paulo, Brazil through synoptic-scale analysis of back trajectories

This study is aimed to qualitatively analyze the impact of remote sources on air pollution in the Metropolitan Area of Sao Paulo (MASP). Air-mass back trajectories from June to August of 1999 were calculated using a three-dimensional kinematic trajectory model and grouped into trajectory clusters. Correlations of individual trajectory clusters with O3, CO and PM10 concentrations were determined. In this model, trajectories were obtained using the means of the three wind velocity components (U, V and W). The three-dimensional wind field was derived from the Regional Atmospheric Modeling System, and downscaling was employed. Coarse and fine nested grids (64-km and 16-km horizontal resolution, respectively) were used. Every 12 h (at 00 and 12 UTC), a back-trajectory ensemble, using the 64-km grid, was calculated for five defined endpoints at intervals of 0.5° N, S, E and W of the MASP (λ = 23° 33′S, ϕ = 46° 45′W), that last endpoint being centered in the MASP. To analyze cluster trajectories, the five trajectory ensembles from each day were allocated into one of four clusters (northeast, southeast, southwest or northwest quadrant) based on the origin of the trajectory over 4 days. Days on which all five trajectories originated from the same quadrant were classified as “core” days. Core day concentrations of CO, O3 and PM10 during the study period were evaluated. The results show that, during the study period, air-mass back trajectories in the MASP originated from all four quadrants: northeast (32%), southeast (12%), southwest (19%) and northwest (37%). Our analysis of back-trajectory clusters in the MASP suggests a transport to ambient air of O3 precursors and O3 from the northeast region, which is associated with agricultural activities involving biomass burning.

A simple photochemical module implemented in RAMS for tropospheric ozone concentration forecast in the metropolitan area of São Paulo, Brazil: Coupling and validation

An in-line simplified photochemical module was coupled with RAMS, an atmopsheric mesoscale model, to produce an operational forecast of ozone and other constituent concentration for the Metropolitan Area of São Paulo (MASP), Brazil. Comparisons between surface pollutants concentrations data, provided by automatic network stations for air quality monitoring and modeled values, show good agreement, with correlation coefficients greater than 0.7 for all stations considered. Mean values over all analyzed stations have an index of agreement higher than 0.8. An important feature observed during the simulations was the ability of the model to simulate nocturnal concentrations of ozone over MASP which are usually observed as a result of transport of this pollutant from other regions and from higher levels of the atmosphere, representing the close coupling between the micro scale process and the chemical reactions, although these nocturnal maximums are overestimated by the model in some cases. The computational efficiency of the model shows that it can be considered for operational procedures with relatively small PC-based clusters and used as a tool for emission control strategies by environmental agencies concerned with the improvement of air quality.

Modeling a densely urbanized watershed with an artificial neural network, weather radar and telemetric data

Artificial neural networks (ANN) are widely used in a myriad of fields of research and development, including the predictability of time series. This work is concerned with one of such applications to simulate and to forecast stage level and streamflow at the Tamanduateí river watershed, one of the main tributaries of the Alto Tietê river watershed in São Paulo State, Brazil. This heavily urbanized watershed is within the Metropolitan Area of São Paulo (MASP) where recurrent flash floods affect a population of more than 17 million inhabitants. Flash floods events between 1991 and 1995 were selected and divided up into three groups for training, verification and forecasting purposes. Weather radar rainfall estimation and telemetric stage level and streamflow data were input to a three-layer feed forward ANN trained with the Linear Least Square Simplex training algorithm (LLSSIM) by Hsu et al. [Hsu, K.L., Gupta, H.V., Sorooshian, S., 1996. A superior training strategy for three-layer feed forward artificial neural networks. Tucson, University of Arizona. (Technique report, HWR no. 96-030, Department of Hydrology and Water Resources)]. The performance of the ANN is improved by 40% when either streamflow or stage level were input together with the rainfall. The ANN simulated flood waves tend to be dominated by phase errors. The ANN showed slightly better results then a multi-parameter auto-regression model and indicates its usefulness in flash flood forecasting.

The effects of air pollution and meteorological parameters on respiratory morbidity during the summer in São Paulo City

Effects of meteorological variables and air pollutants on child respiratory morbidity are investigated during two consecutive summers (December–March 1992/1993 and 1993/1994) at the Metropolitan Area of São Paulo (MASP), Brazil. The MASP, with almost 17 million inhabitants, is considered the most populous region in South America. Due to warmer temperatures, increased rainfall and consequent low levels of air pollutants during the summer compared to winter, less attention has been paid to epidemiological studies during this season, especially in tropical urban areas such as Sao Paulo. In the present work, principal component analysis (PCA) is applied to medical end environmental data to identify patterns relating child morbidity, meteorological variables and air pollutants during the summer. The following pollutant concentrations are examined: SO 2, inhalable particulate matter (PM 10), and O 3. The meteorological variables investigated are air temperature, water vapor (water vapor density) and solar radiation. Although low correlation between respiratory morbidity and environmental variables are, in general, observed for the entire dataset, the PCA method indicates that child morbidity is positively associated with O 3 for the 1992/1993 summer. This pattern is identified in the third principal component (PC3), which explains about 19% of the total variance of all data in this summer. However, the 1993/1994 summer shows a more complex association between both groups, suggesting stronger ties with meteorological variables. Marked changes in synoptic conditions from the end of January to end of March of the 1993/1994 summer seem to have played an important role in modulating respiratory morbidity. A detailed examination of meteorological conditions in that period indicates that prefrontal (postfrontal), hot (cold) and dry (wet) days favored the observed decrease (increase) of respiratory morbidity.

Neural network-based study for predicting ground-level ozone concentration in large urban areas, applied to the Sao Paulo metropolitan area

Events of high concentration of ground-level ozone constitute a matter of major concern in large urban areas in terms of air quality, and public health. In the Sao Paulo Metropolitan Area (SPMA), air quality data generated by a network of air quality measuring stations have been used in a number of studies correlating ozone formation with different variables. A study was carried out on the application of neural network models in the identification of typical sceneries leading to high ground-level ozone concentrations in the SPMA. The results were then applied in the selection of variables, and in the definition of neural network-based models for estimating ozone levels from meteorological variables. When combined with existing weather prediction tools, the models can be applied in the prediction of ozone levels in the SPMA

Air quality model simulating photochemical formation of pollutants: the Sao Paulo Metropolitan Area, Brazil

The main sources of ozone precursors in the atmosphere of the Sao Paulo Metropolitan Area (SPMA) in Brazil are emissions from gasoline-, ethanol-, and diesel-powered vehicles. Ozone is a significant air quality problem in the SPMA. To come into compliance with the National Ambient Air quality Standard for Ozone, emission reduction policies must be established. An adequate emissions inventory and a description of the meteorology and chemistry involved are needed in order to evaluate the effectiveness of methodologies that reduce the effect of vehicle emissions on ozone formation. During the period 10–12 August 1999, concentrations of ozone in the SPMA and the impact of the official emissions inventory were simulated through application of an urban-scale Eulerian model. We found that using the official inventory in simulations resulted in ozone values much lower than those observed and nitrogen oxide emission profiles that were overestimated by a factor of approximately two.

Size-Resolved Mass Balance of Aerosol Particles over the São Paulo Metropolitan Area of Brazil

During an eight-day period in August of 1999, a nine-stage, micro-orifice, uniform-deposit impactor was used to determine the mass size distribution of atmospheric aerosol particles in the heavily polluted Metropolitan Area of São Paulo (MASP) in Brazil. Particle-induced X-ray emission analysis (PIXE) was used to identify up to 20 trace elements in particles collected in the five lower stages. All nine stages, as well as the after filter, were also analyzed for mass, black carbon, and various inorganic ions. A real-time carbon monitor provided organic and elemental carbon concentrations of PM 10 . For the five lower stages, the crustal material concentration was estimated by the sum of the main oxides and carbonates. In the after filter, PIXE analysis was not performed. The averaged mass balance analysis showed that black carbon was concentrated in the after filter, revealing black carbon particles to be very small in diameter. Ammonium sulfate showed simple unimodal size distribution during the day (peak diameter, 0.38 m) and bimodal size distribution at night (0.38 and 0.59 μ m). The crustal material contribution was greater in larger cutoff diameter stages. No explanation was found for a significant fraction of the fine particulate matter. The difference between the mass concentration and the sum of the component concentrations could be attributed to organic carbon being in fine mode. This could explain 38% of the difference and almost all of the missing diurnal and nocturnal mass. Based on these results and assumptions, we can conclude that the fine mode receives a greater contribution from organic and black carbon than from ammonium sulfate. The three together appear to constitute the bulk of fine particulate matter in the MASP.

Dynamics of urban boundary layer over S�o Paulo associated with mesoscale processes

Examination of the Doppler SODAR data from Sao Paulo, Brazil, has given valuable information on the coupling between planetary boundary layer (PBL) and the free atmosphere above, which is reported here. In this communication a case study, on the dynamics of the urban boundary layer over the Metropolitan Area of Sao Paulo (MASP), Brazil, is examined for July 27, 1999 when a multiple gravity wave (GW), a low-level jet (LLJ) and a cold front (CF) all occurred in one single day in succession, making use of data from Doppler SODAR, surface meteorological instruments, satellite imageries and model derived values. The experimental findings are compared to provide validations of ground truth with the model-derived profiles based on the mesoscale analysis of Regional Atmospheric Modelling System (RAMS). It is seen that the multiple GW, the LLJ and the CF have different types of nonlinear coupling between the PBL and the free atmosphere. However, there is convincing matching between Doppler SODAR derived features, those of mesoscale analysis from RAMS and satellite view of cloud dynamics. The study provided valuable information on (i) the very nature of these events, (ii) the nonlinear hydrodynamical coupling between the PBL and the free atmosphere above, during such events, and (iii) the possible mechanism of CF influencing the formation of GW and LLJ.

Evolution of air quality in the Sao Paulo metropolitan area and its relation with public policies

The Sao Paulo Metropolitan Area (SPMA) is one of the largest urban regions in the world, with more than 17 million inhabitants, about 2000 major industrial facilities, and more than 6 million vehicles based on diesel, gasoline, and ethanol. The area is thus a representative example of large urban region. The accumulated data collected by a network of air quality measuring stations, distributed throughout the SPMA, enables the monitoring of the air quality and is an adequate source of information for checking the effect of air quality control measures in the region. The present work shows that, although the levels of primary air pollutants have decreased over the last 20 years, events with high levels of NO 2 , CO, particulate material and ozone still take place. In the last five years ozone has become the most problematic pollutant, in view of the high frequency of peak events. Increased control of emission sources and adequate planning of the urban area, especially concerning the traffic system, are both necessary in order to keep pollution in the area under established levels.

Climatological analysis of wintertime extreme low temperatures in São Paulo City, Brazil: impact of sea‐surface temperature anomalies

AbstractA diagnostic climatological study of winter cold temperature extremes in the Metropolitan Area of São Paulo (MASP) is presented. This diagnosis is based on temperature data collected at the Meteorological Station of Parque Estadual das Fontes do Ipiranga (IAG/USP) from 1950 to 2000. The persistence of synoptic and climatological patterns has been studied through principal component (PC) analysis and the results are compared with monthly anomalies in sea‐surface temperature (SST) of the eastern Pacific and South Atlantic. The extreme cold air temperatures, on a monthly basis, have shown no significant change since 1950. On the other hand, the mean monthly air temperatures have shown a slight warming trend, in agreement with the South Atlantic Ocean warming trend. The PC indicates significant loadings of two SST anomaly types: a cold anomaly of the South Atlantic Ocean, and a warm anomaly off the southern Brazilian coast. The latter could also be responsible for some extreme cold events (for daily minimum temperatures) in the MASP, and to a dominant westerly wind direction (southwest to northwest). Both the cold events and the westerly wind direction were evident in such winters as 1953, 1975, 1978, 1981, and 1994. On the other hand, the cold mean monthly temperatures are very well correlated to a broad cold pool anomaly in the South Atlantic at around 25 to 35° S and 15 to 55° W—sometimes narrower (such as in 1979 and 1988), and sometimes broader (such as 1964 and 1990). Where there was a narrowing or a widening, the prevailing wind direction was from the south–southeast. Therefore, the conclusion of these results is that the SST anomalies in the South Atlantic Ocean have a dominant effect on the São Paulo winter temperature climatology. Copyright © 2002 Royal Meteorological Society.

Heavy metal distribution in recent sediments of the Tietê-Pinheiros river system in São Paulo state, Brazil

The concentrations and possible chemical associations of Al, Fe, Mn, Ca, Cu, Pb, Cd, Zn, Ni and Cr in sediments of the Tietê-Pinheiros river system in São Paulo state, Brazil, were studied using a 3-step sequential extraction protocol recommended by the Standards, Measurements and Testing Programme (SM&T, formerly BCR). A single extraction with 0.1 mol l −1 HCl was applied in parallel to anoxic and air-dried samples. The river system crosses the metropolitan area of São Paulo (MASP), which houses a population of nearly 17 million people, and receives a large load of industrial and domestic wastes. Samples were collected from reservoirs in the surroundings of MASP, named Billings, Pirapora and Rasgão, and from the Barra Bonita reservoir, that is located in the Tietê river, 270 km downstream from São Paulo city. The distribution of metals indicates the recent pollution characteristics for samples from the Billings, Pirapora and Rasgão reservoirs. In these sediments the metals are associated to a large degree with reactive forms such as sulphides and carbonates, or adsorbed to amorphous oxyhydroxides of Fe and Mn. In samples from Barra Bonita, heavy metals are mainly associated with the residual fraction, suggesting that their concentrations are controlled significantly by transport processes with fine particles as carriers from diffuse pollution sources.