65 research outputs found

    Estimation of PM10-bound As, Cd, Ni and Pb levels by means of statistical modelling: PLSR and ANN approaches

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    Air quality assessment regarding metals and metalloids using experimental measurements is expensive and time consuming due to the cost and time required for the analytical determination of the levels of these pollutants. According to the European Union (EU) Air Quality Framework Directive (Directive 2008/50/EC), other alternatives, such as objective estimation techniques, can be considered for ambient air quality assessment in zones and agglomerations where the level of pollutants is below a certain concentration value known as the lower assessment threshold. These conditions occur in urban areas in Cantabria (northern Spain). This work aims to estimate the levels of As, Cd, Ni and Pb in airborne PM10 at two urban sites in the Cantabria region (Castro Urdiales and Reinosa) using statistical models as objective estimation techniques. These models were developed based on three different approaches: partial least squares regression (PLSR), artificial neural networks (ANNs) and an alternative approach consisting of principal component analysis (PCA) coupled with ANNs (PCA-ANN). Additionally, these models were externally validated using previously unseen data. The results show that the models developed in this work based on PLSR and ANNs fulfil the EU uncertainty requirements for objective estimation techniques and provide an acceptable estimation of the mean values. As a consequence, they could be considered as an alternative to experimental measurements for air quality assessment regarding the aforementioned pollutants in the study areas while saving time and resources.The authors gratefully acknowledge the financial support from the Spanish Ministry of Economy and Competitiveness through the Project CMT2010-16068. The authors also thank the Regional Environment Ministry of the Cantabria Government for providing the PM10 samples at the Castro Urdiales and Reinosa sites

    Pollutant profiles as tools for characterisation of environmental exposure

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    This thesis is concerned with measurements of persistent organic pollutants (POPs) in environmental samples. The POPs consist of several groups of compound with many isomers, hence analysing POPs in a complex environment is a This thesis is concerned with measurements of persistent organic pollutants (POPs) in environmental samples. The POPs consist of several groups of compound with many isomers, hence analysing POPs in a complex environment is a challenging task. Studies of the abundance or dynamics of such substances in the environment require careful consideration of several key steps. The environmental and analytical problems must be correctly defined, suitable analytes, sampling strategies and techniques must be selected, the chemical analyses must be reproducible and accurate, and the data evaluation protocols must be rigorous and appropriate. The aim of this thesis was to evaluate the use of pollutant profiles in order to assess complex patterns of environmental exposure. When combined with multivariate data analysis (MVDA) a maximum of information may be extracted from analytical data. Nevertheless, good quality data is essential for correct evaluation of the environmental phenomena under investigation. The precision and accuracy of a solid phase assisted liquid extraction method was therefore assessed by comparison to a reference method. The validated method was used in two human exposure studies. The concentrations of PCBs and dioxins were determined in human tissues from general populations in Sweden and Spain. Although it was concluded that the populations were exposed to similar degree to PCBs and dioxins, principal component analysis (PCA) showed that the compound profiles differed between the populations. PCA was also used to differentiate between occupationally exposed workers and matched controls and between exposed workers with recent and earlier exposure. In addition, the analysis indicated that the differences in PCB patterns in workers with recent and earlier exposure were related to differences in the metabolic degradation rates of individual PCBs. The PCA model was further used to select PCB congeners that were representative of each group. Finally, the emission of polycyclic aromatic hydrocarbons (PAHs) in a traffic tunnel was estimated by measuring 29 individual PAHs. The sampling periods were chosen to reflect a maximum variation in the traffic composition. An excellent prediction of the percentage of heavy-duty vehicles was obtained using partial least squares (PLS) regression. It was shown by PCA that it might be possible to predict source compositions at other locations with the aid of multivariate statistical tools. Thus, properly gathered pollutant profiles and MVDA may be combined to extract a large amount of significant information from environmental source and exposure data

    Parkeringsköp – ett verktyg vid plangenomförande?

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    Few issues raise such an engagement as parking areas, both by the municipality, property- and car owners. For car owners, it is of great importance where to park his car. Parking is not simply about availability but also about safety, security and how it affects the urban environment. When the land will be utilized for building development, there are regulations in Chapter 8, § 9 PBL how parking will be provided. Property owners have an obligation to provide parking space and it shall be arranged in an equitable manner, on the site or near it, which gives an opportunity for shared parking facilities. The guidelines for parking that the municipality has adopted should be the starting point for the extent of that space for parking is required when a building permit review. The first thing you should look at, is if the property owner has ability to provide parking space at his own property, but this is not always the best solution in areas such as inner cities. To solve the issue on another property near the property, there are a number of different possibilities for the property owner to resolve the parking issue. It may be through an easement, either as official easement or easement agreements. If the facility is intended to be shared by multiple properties as a joint facility, it can be established by Facilities Act. Common parking facilities may also take place at the initiative of the municipality or by a private operator. The finished parking areas can then be leased by a tenancy agreement. Parking purchase is another way to solve the parking issue. The public legal obligation to provide parking space is then transformed, through a civil contract, to an obligation to financially contribute to a municipal or private parking facility. All solutions have both positive and negative aspects, such as, regulating the costs of operation and maintenance of plant, the agreement can be terminated, etc. which we illustrate by this report
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