Catálogo de publicaciones - libros

The degradation of environmental quality in many regions of the world has accelerated during the past decades especially due to the industrial development, which has led to important changes in different compartments of the environment. Important atmospheric species are considered to be responsible for wide spread environmental effects including, changes in pH deposition, corrosion of buildings material etc. Deposition of air pollutants is an important loss process for most of the species present in the atmosphere that can cause severe damage to ecosystems. Air pollutants are deposited to the earth’s surface especially through wet and dry processes. Deposition rates are determined in order to estimate the impact of these pollutants on ecological systems. Deposition of pollutants by wet processes is relatively easy to determine through analysis of precipitation samples. However, it is well recognised that less is known about dry deposition, which is much more difficult to measure (estimated using measured air concentration and the deposition velocity concept) and which appears to predominate near strong emission sources with wet deposition predominating further downwind (Whelpdale ., 1997). Direct measurement of pollutants deposition by dry processes is more difficult and requires extensive instrumentation and technical resources.

During last years the negative effects of anthropogenic pollution on the environment has intensified. The effects are observed on the regional and local levels in the change of the environment quality, as well as on the global level as in the change of the planet climate. Urban agglomerations play an important role in these processes.

Since many years there has been increased interest in the investigation of chemical processes taking place in the polluted atmosphere. Definite relationships exist between chemical reactions which occur in the atmosphere in the gas, liquid and solid phases under stationary conditions.

At present, in the mountain regions of Tien-Shan and Pamir reduction and vanishing of glaciers is occurring. According to glaciological data, 1081 glaciers disappeared at Pamir and Alai between 1957 and 1990, and 71 glaciers have completely thawed at Zailijsky Ala Tau. The glaciers recede with an average velocity of 8 meters per year. Not only is the linear size of glaciers reduced, but also their volume. This influences significantly river waters, vegetation and Central Asian climate.

Investigations were conducted at urban and rural sites of the Dniepropetrovsk Province (Ukraine) during the last decade, and were aimed at an assessment of the air pollution and the buffer capacity of local ecosystems. The following themes were considered in the study: the regional distribution of industrial emissions, the structure of the ecosystems, an estimation of the buffer capacity of the soil and vegetation cover.

The measurement of air pollution parameters is a costly process. Due to several reasons, the devices may not take measurements for certain days. In such cases robust estimation methods are quite necessary in order to fill the gaps in the time series. Artificial neural networks have been employed successfully for this purpose for hydrometeorological time series, as reported in literature. In this study, modelling of the time series of air pollution parameters was investigated using two ANN methods; a radial basis function algorithm (RBF) and feed forward back propagation method (FFBP). The ANN methods were employed to estimate the PM10 values using the NO and CO values. The data were from a measurement station in Istanbul, Turkey. The results of an initial statistical analysis were considered in the determination of the input layer node number. In the estimation study, values corresponding to other air pollution parameters were included in the input layer. The results were compared to those obtained with a conventional multi-linear regression (MLR) method.