S. Tascini

A Simplified Approach To Photochemical BoxModel Meteorological Data Input

One of the most important meteorological input parameter for photochemical air pollution models is the mixing height h mix , which has a strong influence on the shape and intensity of the vertical diffusivity and, as a consequence, on ground level air concentration of primary and secondary pollutants. In this paper the analytical model of the boundary layer height proposed by Gryning and Batchvarova has been taken into consideration. A new meteorological input, developed according to specific requirements, has been developed to supply input data to a simple numerical air quality model (Photochemical Box Model) that simulates urban scale photochemical smog evolution.

Assessing the representativeness of thermal comfort in outdoor spaces

This paper presents preliminary findings of an outdoor thermal comfort study conducted in an urban area to evaluate the representative Predicted Mean Vote index. Thermal comfort in outdoor urban spaces is often faced with the task of using large amounts of data that yields meaningful information concerning the thermal sensation. It is essential to interpret correctly meteorological and thermal comfort data. In particular, it is important to interpret data using an appropriate statistical analysis, and the analysis of thermal comfort presupposes a synthesis of information derived from a series of temporal data. It is indispensable to deal with realistic data and an actual day should be considered, but the widely used average day is not an actual day. On the contrary, the representative day is made of the actual data of the day, in the period considered, where the sum of the mean-square differences among its monitored quantities, averaged within each hour, and the same quantities for all other days at the same hour, is minimised. The goal of this research is to assess the representativeness of the thermal comfort indices provided using a representative day technique. Specifically, a new tool has been developed using a powerful and useful environment for symbolic and numerical computing and data visualization such as Wolfram MathematicaTM, aiming at linking information computed by a bio-climate model to the representative day technique. The possibility of assessing the diurnal variation of PMV thermal comfort index by introducing the Representative Day technique has been evaluated in order to gather information on the correlation between thermal comfort and meteorological parameters. A case study has been analysed in order to improve the microclimate in an outdoor space located in a typical Mediterranean area and a comparison with CFD code, namely ENVI-MET, has been reported. This technique can prove to be a very

Importance Of Local Meteorology In Coastal Ozone Dynamics: A Case Study

Ozone dynamics are strictly dependent to meteorological conditions. Solar radiation, pressure distribution and horizontal wind field, along with precursor concentrations, play fundamental roles in ozone formation and depletion. The present case study concerns Falconara, an Italian town located on the Adriatic sea, which presents several air pollution modelling issues: complex orography, location at the mouth of Esino river and the presence of several distributed and point precursor sources. During the summer 2000 strong ozone episodes have been recorded in disagreement with other typical pollution concentration levels. The aim of our work was to investigating the role played by meteorological scenarios that may favour ozone formation, stagnation and recirculation. For this purpose RAMS simulations have been implemented by assimilating data from provincial monitoring network and from European Center for Mediumrange Weather Forecast elaborations. The simulation domain is represented by four regular nested grids: the first grid is an 18x18 mesh with a 50000m side width; the finest grid is a 37x37; the four nesting ratios are respectively 1,5,5,5. Simulations have been carried out for three significant days in the month of August (9, 12 and 23) and explained the evolution of critical quantities (namely wind, pressure and humidity) during those periods. Results show the existence of meteorological scenarios suitable for Tropospheric Ozone production and the persistence of re-circulation phenomena (namely stable sea breezes) with consequent pollution low depletion and accumulation. Peculiar coastal phenomena have also been highlighted, such as breeze fronts capable of significant increment of both ozone and precursor concentrations. Transactions on Ecology and the Environment vol 66,

A Preliminary Evaluation Of UnexpectedOzone Levels Measured In Falconara, Italy

Ozone is a secondary pollutant that forms in the atmosphere through complex chemical reactions mainly between Nitrogen Oxides ( NOx ) and Volatile Organic Compounds (VOC ); such reactions are triggered by the presence of solar radiation. In this paper the Ozone formation in the Falconara area, an industrialized area located on the central Adriatic coast of Italy, has been examined during a period of high ozone concentrations that occurred in August 2000 to understand spike phenomena registered in some ozone time series. The selected data set consists of concentration hourly averages and related elementary values, both provided by the monitoring network of Ancona Province, Italy. We have analysed hourly averages to investigate the long-term and medium-term behaviour of pollutants, while elementary values have been used to study scattering phenomena (low frequency and high frequency fluctuations in concentration levels) registered in some ozone time series. Spectral analysis has been performed over the air pollutant time series; the focus has been set on photochemical pollutants traced by ozone concentrations, considering potential correlations with chemical precursors, and atmospheric parameters such as solar radiation, wind velocity and air temperature. Analyses conducted led to the hypothesis that the processes that generate ozone in Falconara are more rapid and efficient than in other urban areas, and that ozone production varies significantly over shorter spatial scales than in other urban areas. Results have yielded possible explanations regarding the origins of the oscillations. www.witpress.com, ISSN 1743-3541 (on-line)