Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.

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Climate Change 2007: The Physical Science Basis.

The science of the total environment

openair is an R package primarily developed for the analysis of air pollution measurement data but which is also of more general use in the atmospheric sciences. The package consists of many tools for importing and manipulating data, and undertaking a wide range of analyses to enhance understanding of air pollution data. In this paper we consider the development of the package with the purpose of showing how air pollution data can be analysed in more insightful ways. Examples are provided of importing data from UK air pollution networks, source identification and characterisation using bivariate polar plots, quantitative trend estimates and the use of functions for model evaluation purposes. We demonstrate how air pollution data can be analysed quickly and efficiently and in an interactive way, freeing time to consider the problem at hand. One of the central themes of openair is the use of conditioning plots and analyses, which greatly enhance inference possibilities. Finally, some consideration is given to future developments.

openair - An R package for air quality data analysis

In order to use environmental models effectively for management and decision-making, it is vital to establish an appropriate level of confidence in their performance. This paper reviews techniques available across various fields for characterising the performance of environmental models with focus on numerical, graphical and qualitative methods. General classes of direct value comparison, coupling real and modelled values, preserving data patterns, indirect metrics based on parameter values, and data transformations are discussed. In practice environmental modelling requires the use and implementation of workflows that combine several methods, tailored to the model purpose and dependent upon the data and information available. A five-step procedure for performance evaluation of models is suggested, with the key elements including: (i) (re)assessment of the model's aim, scale and scope; (ii) characterisation of the data for calibration and testing; (iii) visual and other analysis to detect under- or non-modelled behaviour and to gain an overview of overall performance; (iv) selection of basic performance criteria; and (v) consideration of more advanced methods to handle problems such as systematic divergence between modelled and observed values.

Position paper: Characterising performance of environmental models

The Structure of Turbulent Shear Flow By Dr. A. A. Townsend. Pp. xii + 315. 8¾ in. × 5½ in. (Cambridge: At the University Press.) 40s.

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The Structure of Turbulent Shear Flow

The understanding of the behaviour of pollutants released in urban sites is of paramount importance for a number of reasons, mainly related to human health. Furthermore, the particular present international political situation adds further concerns, as the deliberate discharge of toxic material in populated areas is a serious threat. Wind tunnel experiments were performed in order to study flow and pollutant dispersion in a real urban environment. The work is part of a larger EPSRC funded project (DAPPLE, Dispersion of Air Pollution & Penetration into the Local Environment) involving six British Universities.

Poster 1 Mass flux balance at an urban intersection

R.N. Colvile, S. Kaur, S. Belcher, M. Bell, R. Britter, M. Nieuwenhuijsen, A. Robins, A. Tomlin, D. Shallcross Imperial College London, Department of Environmental Science & Technology, London, UK University of Reading Department of Meteorology, Reading, UK University of Leeds Institute for Transport Studies, Leeds, UK University of Cambridge, Department of Engineering, Cambridge, UK University of Surrey, School of Mechanical Engineering, Guildford, UK University of Leeds Department of Fuel & Energy, Leeds, UK University of Bristol Department of Chemistry Bristol, UK

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Personal exposure to air pollution at a street canyon intersection: implications for air quality management in the context of sustainable development

Blackett Review on wide-area biological detection

Suitable dispersion models are required for the p rediction of nanoparticle number concentrations for adopting mitigation policies. The aim of this work is to model the dispersion of nanoparticle number concentrations in the 10-300 nm range at different heights in an urban street canyon. A modified Box model (Kumar et al . 2009b) and an operational street pollution model (OSPM) are used for this purpose and modelled results are compared with the measured nanoparticle concentrations. Further, the article discusses the role of particle dynamics in street-scale modelling and analyses the influenc e of the uncertainty in particle number emission fa ctors on modelled concentrations. Reasons for discrepancies in modelled results due t o particle number emission factors and street-level particle dynamics are given.

Alan Robins

Papers

Poster 1 Mass flux balance at an urban intersection

Personal exposure to air pollution at a street canyon intersection: implications for air quality management in the context of sustainable development

Blackett Review on wide-area biological detection

Modelling the dispersion of nanoparticles in street canyons

Group riding: Cyclists exposure to road vehicle emissions in urban environments