The increasing level of noise generated by the modern environment around us, particularly road and rail transport, has a detrimental impact on our health, both physical and mental. The concept of noise refers to sounds that we subjectively perceive as unpleasant – most often these are long-lasting sounds of high intensity that do not occur naturally in nature. Noise that persists constantly leads to a drastic degradation of hearing, reduces concentration, causes pain and discomfort.
To easily understand the essence of noise in contrast to pleasant sounds, one can think of different types of music, which for one listener can be pleasant and relaxing, while for another irritating. On the other hand, noise is also a physical factor that can be precisely analyzed by measuring values such as acoustic pressure, sound frequency and sound level. Depending on the levels of these parameters, noise affects the surrounding environment in a way proportional to their size.
Noise is a complex and difficult phenomenon in modern society, which is very mobile and moves daily in every direction using every possible means of communication. Each means of communication generates sounds that arise from the work of mechanical parts such as engines, however, it should not be forgotten that a large amount of noise is also generated by the friction of tires against the road surface (train wheels against the tracks on which they move) and the air that is constantly “pierced” by speeding vehicles. The effects of ubiquitous noise and its impact on societies in the form of physical and mental strain have been the subject of numerous scientific studies in recent years.
Noise and its consequences are also the subject of a special report by the German Environmental Council “Umwelt und Gesundheit” (Environment and Health). The noise level, especially on our roads, is constantly rising, becoming one of the most serious and most common problems in industrialized countries. In densely populated and industrialized countries, noise is a bigger problem than any other environmental pollution generated by industry.
Road traffic is noticeably the most responsible for generating most of the noise in cities, ahead of the noise generated by airport operations and rail traffic.
Estimates indicate that around 20% of the European Union population (i.e. around 80 million people) are exposed to traffic noise exceeding 65 dB(A) on a daily basis. The main source of noise is road traffic (according to various sources, approx. 70% – 80%), followed by air and rail traffic.
According to a field study by HAINES et al. (1998) on people’s habituation to traffic noise, our perception of noise remains the same at a constant noise level. What is extremely important, the study does not indicate that the human ear gets used to noise.
If exposure to noise persists for a longer period, it is classified as negative stress, which very often manifests itself in physical reactions. One of the results of stress caused by noise are hormonal reactions, including the release of adrenaline, noradrenaline and cortisol. These hormones affect the cardiovascular system, metabolism, blood fat levels and blood pressure. A long-term increase in cortisol levels can lead to atherosclerosis and higher cholesterol levels. As secondary effects, sleep disturbances appear.
It has been established that there is a threshold value for increasing the risk of heart attack associated with noise, which is 60 dB(A) during the day and 50 dB(A) at night. This level and above triggers the release of larger amounts of stress hormones even during sleep, even when the noise does not wake up sleeping people. At this noise level, the risk of heart attack increases by 20%. Noise is therefore a serious risk to our health that we are exposed to and to which we must react.
Despite various measures, such as noise limits for motor vehicles specified in EU Directive 2001/43/EC, recommendations for the development of quieter tires and noise-reducing road surfaces, noise cannot be completely eliminated.
Acoustic Screens as Effective Noise Reducers Along Roads and Noise-Generating Locations
Noise barriers along heavily used traffic routes reduce the noise burden on the environment without taking up too much space and without interfering with the landscape (in the case of transparent screens). The noise problem is very noticeable by society, which does not allow it to be left uncontrolled, which is reflected in regulations on the permissible noise levels that can be emitted by a communication route. Legal provisions also define a number of properties that screens must have. They define strength characteristics, fire resistance and the type of screens from an aesthetic point of view (whether the screen is to be transparent or opaque is allowed), sound-absorbing or reflecting, etc. Detailed noise control, together with recommendations on how to reduce noise along roads, is becoming increasingly important in the face of increasing traffic intensity.
