Neyval Costa Reis

Modeling and forecasting daily average PM10 concentrations by a seasonal long-memory model with volatility

This paper considers the possibility that the daily average Particulate Matter (PM10) concentration is a seasonal fractionally integrated process with time-dependent variance (volatility). In this context, one convenient extension is to consider the SARFIMA model (Reisen et?al., 2006a,b) with GARCH type innovations. The model is theoretically justified and its usefulness is corroborated with the application to PM10 concentration in the city of Cariacica, ES (Brazil). The fractional estimates evidenced that the series is stationary in the mean level and it has long-memory phenomenon in the long-run and, also, in the seasonal periods. A non-constant variance property was also found in the data. These interesting features observed in the PM10 concentration supports the use of a more sophisticated time series model structure, that is, a model that encompasses both time series properties seasonal long-memory and conditional variance. The adjusted model well captured the dynamics in the series. The out-of-sample forecast intervals were improved by considering heteroscedastic errors and they were able to capture the periods of more volatility. SARFIMA-Garch model is proposed.Properties of the model estimation are established.The series PM10 concentration was used as an example.The model is an alternative tool to obtain good forecasts in the air pollution area.

Impact assessment of odours emitted by a wastewater treatment plant

Complaints from the Domingos Martins population about sewage odours in the city made the district attorney order an impact assessment of the odours emitted by the city wastewater treatment plant (WWTP). This study comprised various techniques, models and population surveys. In 2007, an odour emission model proved that the main hydrogen sulphide emitter was the aeration tank of the WWTP (13.5 g h(-1)) and such emissions, according to CALPUFF model, should be perceived in the whole Domingos Martins city centre area. In this area, 58% of those interviewed were annoyed by the WWTP odours. However, in 2009, the odour monitoring panel recorded few odour occurrences. A second population survey showed that hereafter only 20% of those interviewed were annoyed by the WWTP emissions. Odour emission and dispersion models run with 2010 data proved a drastic reduction of the WWTP aeration tank emissions and consequently the city centre was not bothered by WWTP emissions anymore. The odour emission reduction was due to the modification of the WWTP aeration tank system. Despite the odour emission reduction, houses located southeast of the WWTP were still annoyed by sewage odours. However, in this part of the town, other sources of sewage odours have been found.

Evaluation of weather research and forecasting model parameterizations under sea-breeze conditions in a North Sea coastal environment

Three atmospheric boundary layer (ABL) schemes and two land surface models that are used in the Weather Research and Forecasting (WRF) model, version 3.4.1, were evaluated with numerical simulations by using data from the north coast of France (Dunkerque). The ABL schemes YSU (Yonsei University), ACM2 (Asymmetric Convective Model version 2), and MYJ (Mellor–Yamada–Janjic) were combined with two land surface models, Noah and RUC (Rapid Update Cycle), in order to determine the performances under sea-breeze conditions. Particular attention is given in the determination of the thermal internal boundary layer (TIBL), which is very important in air pollution scenarios. The other physics parameterizations used in the model were consistent for all simulations. The predictions of the sea-breeze dynamics output from the WRF model were compared with observations taken from sonic detection and ranging, light detection and ranging systems and a meteorological surface station to verify that the model had reasonable accuracy in predicting the behavior of local circulations. The temporal comparisons of the vertical and horizontal wind speeds and wind directions predicted by the WRF model showed that all runs detected the passage of the sea-breeze front. However, except for the combination of MYJ and Noah, all runs had a time delay compared with the frontal passage measured by the instruments. The proposed study shows that the synoptic wind attenuated the intensity and penetration of the sea breeze. This provided changes in the vertical mixing in a short period of time and on soil temperature that could not be detected by the WRF model simulations with the computational grid used. Additionally, among the tested schemes, the combination of the localclosure MYJ scheme with the land surface Noah scheme was able to produce the most accurate ABL height compared with observations, and it was also able to capture the TIBL.

Volatilization of hydrogen sulfide from a quiescent surface.

Air-water mass transfer of hydrogen sulfide from a shallow tank with a quiescent surface under the influence of weak wind stress on the water surface was studied numerically using a two-dimensional model. The flow field in the tank was investigated using a computational code based on a finite volume, which is used to numerically solve momentum, mass and continuity conservation equations. The results show that water phase flow field is strongly dependent on the wind-induced surface velocity and the aspect ratio of the tank. Based on the numerical study, the liquid-side mass transfer coefficient is correlated with Reynolds number (R(e)), tank aspect ratio (AR) and Schmidt number (S(c)). Overall mass transfer coefficient (K(L)) values extend further downstream as the R(e) number increases.

Automatic methods to detect the top of atmospheric boundary layer

The main objective of this work is to obtain methods that automatically allow qualitative detections of Atmospheric Boundary Layer heights from LIDAR data. Case studies will be used to describe the more relevant days of a campaign carried out in July of 2012 in Vitória, Espírito Santo, Brazil. The data analysis compares three mathematical algorithms that automatically provide the ABL height: Gradient Method (GM), using the derivative of the Range Corrected Signal (RCS) logarithm, WCT (Wavelet Covariance Transform), and Bulk Richardsons Number, which was used to validate the methods mentioned above. The comparison between the methods has shown that as the presence of clouds and the aerosol sublayer increased, the more sensitive was the refinement needed to choose the “right” parameters, whereas even Richardson’s method had ambiguities in finding a good estimate of the ABL top.

Numerical modelling of odour dispersion around a cubical obstacle using large eddy simulation

In the present work two different large eddy simulation (LES) approaches, namely the Dynamic Smagorinsky model and the Wale model, are used to simulate the air flow and pollutant dispersion around a cubical obstacle. Results are compared with wind tunnel data (WT) and with results from the Smagorinsky LES model. Overall agreement was good between the different LES approaches and the WT results, both for the mean and fluctuating flow and concentration patterns. LES models can provide good estimates of concentration fluctuation intensity and enable the calculation of the intermittency factor. The model results indicate that LES is a viable tool for odour impact assessment.

Use of inorganic and organic markers associated with their directionality for the apportionment of highly correlated sources of particulate matter

Particulate matter source identification using receptor models is one of the tools applied in air quality management. These models have limitations such as the collinearity effects, hindering their application and interpretation. Positive Matrix Factorization (PMF) models use chemical markers for the definition of likely sources, leaving to users the factors interpretation. This can lead to biased interpretations, as chemical species can be markers for several sources, particularly when there is source similarity. The Region of Greater Vitória, located southeast of Brazil, is a complex site in which similar industrial activities are installed, such as a pelletizing plant and a steel plant, that produce iron pellets and sinter, both iron-agglomerates with similar chemical profiles. To minimize the effects of collinearity between those sources, a new PMF approach is proposed by using inorganic and organic chemical species and the directionality of pollutant using wind roses. The proposed methodology determines the following consolidated markers: elemental carbon (EC) and organic carbon (OC) for vehicular sources; chloride (Cl) and sodium (Na) for sea salt; iron (Fe) for industrial sources. This association was possible by identifying the directionality of the chemical species. Cl a typical sea salt marker also attributed to industrial sintering activities. Some PMF factors showed high OC loadings, a typical marker for both vehicular exhaust and coal burning. The definition of the most appropriate sources for those factors was only possible due to the assessment of the pollutant roses. Pollutant roses generally showed that higher concentrations of potassium (K), a marker of biomass burning, was predominantly associated with winds from an industrial park, and are most likely associated with sintering emissions. Results showed that combining both organic and inorganic markers with the pollutant roses for identification of the directionality of predominant sources improved the interpretation of PMF factor numbers in source apportionment studies.

Inventário de Emissões com Alta Resolução para a Região da Grande Vitória Utilizando o Sistema de Modelagem Integrada WRF-SMOKE-CMAQ

Atmospheric pollution from anthropogenic activities has been bothering the population of Great Vitoria Region (GVR), Espírito Santo, Brazil. Some people are particularly vulnerable to poor air quality: those affected by health conditions such as asthma, allergies, chemical sensitivity, heart disease, stroke and diabetes, as well as pregnant women, children and people of advanced age. Atmospheric pollutants complex interactions can be understood by using chemical transportation models, which require emissions inventories to provide spatial and temporal allocation of emissions. The emissions inventory of GVR on 2010 has been provided by the State Institute of Environment (IEMA). On this study, the regional sources inventory has been adapted to Sparse Matrix Operator Kernel Emissions (SMOKE) in order to be used on Air Quality Models (AQM) such as Community Multi-scale Air Quality (CMAQ) modeling system and other photoRevista Brasileira de Meteorologia, v. 33, n. 3, 521-536, 2018 rbmet.org.br DOI: http://dx.doi.org/10.1590/0102-7786333011

Resonant Synchrotron X-ray Diffraction determines markers for iron-rich atmospheric particulate matter in urban region

Particulate matter driven health problems are strongly associated with its chemical composition. Despite the benefits of using source apportionment models for air quality management, limitations such as collinearity effects, restrict their application or compromise the accurate separation of sources, particularly for particulate matter with similar chemical profiles. Receptors models also depend on the operator expertise to appropriately classified sources, a subjective process that can lead to biased results. For highly correlated sources, the identification of specific markers is still the best way to achieve proper source apportionment. In this study, Resonant Synchrotron X-ray Diffraction has been applied to the analysis of atmospheric particles to determine markers for industrial and vehicular sources in the Region of Greater Vitória, Brazil. Total suspended particulate matter, PM10, and PM2.5 samples were analyzed by Resonant Synchrotron X-ray Diffraction showing high levels of iron-based crystalline phases. In comparison to the use of chemical elemental species, the identification of the crystalline phases provided an enhanced approach to classify specific iron-based source markers. For this study, α-Fe2O3 was identified with iron-based sources such as iron ore, pelletizing, and sintering; metallic Fe was inferred with blast furnaces and steelmaking; FeS2 was correlated with coal deposits; and K2Fe2O4 was associated to sintering emissions. Elemental carbon with different X-ray diffraction patterns enabled the differentiation of industrial and vehicular sources. The attribution of crystal rather than elemental composition in the identification of sources improves the accuracy of source apportionment studies.

Indoor air quality in an Antarctic Research Station: Fungi, particles and aldehyde concentrations associated with building materials and architectural design

Antarctic buildings are enclosed structures, which provide shelter and logistic support to researchers and personnel who remain indoors for long periods and can be affected by air pollution caused by construction materials and activities inside buildings. This study aims to investigate the indoor air quality at the Brazilian Comandante Ferraz Antarctic Station based on measurements of aldehydes, particulate matter and fungi conducted during the Antarctic summer in 2012. The sampling site was divided in conditioned (personnel living quarters) and unconditioned (service and utilities areas) compartments and outdoor sites. A field log book was used to record the activities in the station. Furniture and plywood coverings may have contributed to high average concentrations of formaldehyde. Cooking resulted in high average levels of acrolein and fine particles in most of the monitored environments. Other activities such as cleaning, use of personal and cosmetic products, waste incineration, building maintenance and movement of people and vehicles have also contributed to particles concentration increase. Dominance of the species Aspergillus versicolor and Penicillium sp. showed potential means of fungal proliferation. Considering that the functionality and operation are similar in many Antarctic buildings, some general recommendations were outlined.