Atmosferik kirleticilerin kuru ve ıslak çökelme mekanizmalarının kireçtaşlarındaki parlaklık kaybına etkisi

Abstract

İnsanoğlunun ortak varlığını oluşturan ve yaşamsal ve toplumsal olarak vazgeçilmesi imkansız değerler bütünü olan çevre, zamanla insanın yaşamsal faaliyetlerindeki birtakım değişimlerle, olumsuz bir sürece girerek, tüm canlıların doğal yaşam ortamlarının bozulmasına ve kirlenmesine yol açmıştır. Nüfus artışı, sanayileşme ve kentleşme üçgeni arasında biçimlenen bu yeni yaşam ortamı, yaşadığımız yüzyılın en büyük çevre kirliliği sorunu olan ve yeryüzündeki yaşamsal faaliyetler açısından büyük bir öneme sahip hava kirliliğini ortaya çıkarmıştır. Ve canlı ve cansız bütün varlıklar üzerindeki olumsuz etkilerinin, tarihsel ve kültürel değer içeren yapılar ile günümüz yapılarında da görülmesi, hava kirliliğinin, birçok alanda olduğu gibi, mimarlık disiplini içerisinde de ele alınmasını ve araştırılmasını kaçınılmaz hale getirmiştir. Bu bağlamda yaklaşılan tez çalışmasında, yapılar üzerine "Kuru ve Islak Çökelme Mekanizmaları" şeklinde, iki farklı yoldan ulaşan atmosferik kirleticilerin etkileri ve bu etkilerin, farklı ortamlarda ve konumlarda yer alan kireçtaşları üzerinde meydana getirdiği parlaklık değişimlerinin deneysel bir yöntem ile desteklenerek incelenmesi yönünde bir araştırmaya gidilmiştir. Araştırmadan elde edilen bulguların değerlendirilmesi ile de, atmosferik kirleticilerin, kuru ve ıslak çökelme mekanizmalarının kireçtaşları ile olan etkileşiminin ve kimyasal reaksiyonunun, hava kirliliği seviyesi, meteorolojik faktörler, yağmur suyunun asitliliği, kireçtaşı örneklerinin yerleştirildiği bölgelerin yapısı ve durumu, kireçtaşlarının bu bölgeler içinde bulunduğu konum, reaksiyon süresi, kireçtaşlarının karakteristik özellikleri ve kimyasal yapıları gibi temel faktörlere bağlı olduğu ve ister kuru çökelme, isterse ıslak çökelme mekanizmalarının etkisiyle olsun, kireçtaşları üzerinde, çok kısa süreçler sonunda dahi parlaklık kaybı meydana geldiği ve bu parlaklık kaybının da, kireçtaşlarının bünyesinde, bundan sonra ortaya çıkabilecek hasar ve bozulmaların başlangıcını oluşturduğu bulunmuştur.

Environment is a set of values that constitutes human beings common ground and is too important to forgo. Thus, any of life elements such as air, water and soil, plant and animal communities sharing these elements with human beings and all the civilizations that human beings created in the course of history is an environmental value. But, from the beginning of the human being existence, the interaction that continues with these values, went to a negative period, by the variation in the vital activities of human being and causes the natural life environments of the whole living creatures, become spoiled and dirty. Especially, after the beginning of the industrial revolution, human living environments shaped with the anxiety of industrialization and urbanization and this brought a bigger load for the nature to renewal itself. Urbanization accelerated by industrialization, causes huge ratios of population growth. This population, which is spread out to a wide physical area, caused high density, heterogeneous, industrial society cities. The effects of the activities, to supply the urban services, to the environment, has become greater, as the cities grow. And high population growth, urbanization and industrialization, altogether, caused air pollution, the greatest environment problem. As the air pollution increases and spreads out in a great amount, beyond the local boundaries, it become a big problem, that damages the ecological equilibrium (including not only the human health, but also the plant and animal communities) and the buildings. Because of having a great role for the living and inanimate bodies must be known. And this necessity, brings the air pollution to be considered in the architecture dicipline, as the other career diciplines. Especially for the buildings that has a cultural and historical value and for today's buildings and the materials and components that constitutes this buildings must be examined and analysed for the effects of the air pollution. The solid and liquid fuels used even in heating buildings or transportation vehicles, are the most important factors for the formation and growing to maximum amounts of the air pollution. Especially, the polluters, that are found in a high amount in the atmosphere, like S02 (sulfurdioxide), forms by the use of these fuels, goes into chemical reactions, by reaching to the building surface materials from two different ways, called as "Wet and Dry Deposition Mechanisms" by the catalysor effect of the meteorological factors like rain, relative humidity, fog, wind and sun radiation. And this chemical reactions causes different types of damage formations, according to the materials chemical structure and characteristics. In this study, the effect of dry and wet deposition mechanism of the atmospheric polluters was searched for the loose of brightness of the limestones, that are located in different regions of an urban settlement, having different settlement properties. And it was considered that these loose of brightness, will be the beginning of the damages and failures in the limestone on the following stages. The most important problem, for the effect of the air pollution on the dry and wet deposition mechanisms on the limestone and examine the variation in the brightness of the limestone is, to distinguish the differences between the effect of the wet and dry deposition mechanisms. To distinguish these differences, practically, a hypothesis is set, to define the effect of the wet deposition mechanism, limestone examples exposed to direct rain effect, while to define the effect of dry deposition mechanism, limestone examples exposed to direct atmospheric conditions but sheltered from the direct effect of rain. xi And the second problem is, where would the examples of limestone will be settled in Eskişehir. Knowing that, settling the examples of limestone in only one region of Eskişehir, will cause some mistakes to get the correct results, limestone examples settled in two different regions of Eskişehir. Having different properties of these two different regions, the first region is close to city centre, while the other region is choosed away from the city centre, in Anadolu University Campus. Because of either controlling the limestone examples or measuring PH degrees of rain and snow waters degrees correctly, working regions limited by choosing only these two regions. And then, four different types of nearly 250 limestone examples, placed in two different positions (exposed to direct rain and sheltered from rain). For 16 months, one of these limestone examples, was picked up in every month. At the end of 16 months, the limestone examples picked up, was examined under the bulb light and for making an evaluation, these limestone examples were examined by naked eye. So that a method is constituted to define the lost of brightness of these limestone examples. With this examination, it was seen that, limestone examples categorized in three different groups, classified as bright, semi bright/semi mat and mat. For 16 months, the difference of these 236 limestone examples, in four different types, processed on the "Brightness Variation Tables". By these tables prepared, it was shown that in both different regions and situation, which behaviour does every limestone shows, according to the variation of brightness. And also, with these tables, it was discovered that, which regions and situations are effective according to the lost of brightness for the limestone by the wet and dry deposition mechanism of atmospheric polluter. Thus, a general result is obtained from the effect of wet and dry deposition mechanisms and the effect of these mechanisms for the limestone, according to the lost of brightness. xn According to these conclusions:. Meteorological factors like wind, relative humidity, fog, sun rays and ratiation, have catalysor effects on the lost of brightness of limestone by the formation of dry and wet deposition mechanisms of the polluters; but it is very difficult to explain which conditions and amounts are these factors are effective.. There is a relative relation between the PH value of rain (or snow) water and air pollution degree. Parallel to the increase or decrease of air pollution degrees, the rain water gains acidic or basic character.. Air pollution is the only reason for the lost of brightness of the limestone and the regions properties. Also situation has an important effect for the air pollution to increase or decrease.. Dry and wet deposition mechanisms are chemical reactions, where wet deposition mechanism happens on the upper parts of the atmosphere while dry deposition mechanisms happen on the close parts to the earth's of the atmosphere.. While the situation of the stones are important in the wet deposition mechanism, it is not important in dry deposition mechanism. Dry deposition mechanism is effective on the limestones that are sheltered from the direct effect of rain, beside this, it is effective on the limestones that are exposed to the rain effect, in the dry terms (seasons).. In wet deposition mechanism, which is formed in the atmosphere, the lost of brightness in the limestone, happens in a very short period of time (only in rainy, foggy or high relative humidity seasons). Wet deposition mechanism has more aggressive and brightness loose effect, than dry deposition mechanism, which has a longer period, even for the formation in the atmosphere or interaction with the limestone (except from rainy, foggy or high relative humidity seasons).. The physical, chemical and technological properties that defines the characteristics of limestone, don't have a direct effect for the loose of xin brightness. Such that, even the limestones which seem like having weak characteristics, will show a converse reaction for the loose of brightness. The chemical structures of the limestones, which are dominant according to characteristic properties, shows a limited relation with the limestones brightness. Consequently, even for the short periods of time, the loose of brightness can be observed on the limestones by either dry or wet deposition mechanisms of the atmospheric polluters. And this loose of brightness will be the beginning of the damages and defects for the limestone, in the following stages. Thus, the characteristic properties and chemical structures of the limestones, that will be used on the outer walls of the buildings, should not be the only factor that will define the choose of the limestone. And the brightness values that will be obtained from the research made in both laboratory conditions and natural atmospheric environment, must be the main criterion in choosing limestones.