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Environmental issues near roads become more and more important in our society daily life. One of the most critical environmental issues is traffic noise. The present paper study louvred noise barrier designed by authors. The louvred noise barrier provides sound attenuation while allowing airflow and sunlight through it. Since the airflow resistance of the barrier is low, it requires a shallow foundation compared to conventional noise barriers. The sound attenuation performance of the louvred noise barrier was tested experimentally in a sound transmission chamber. Airflow resistance simulated using a computational fluid dynamics model. The simulation and experimental study were done with different louvred noise barrier setup: change of louvre blade angle and sound-absorbing material thickness. The results showed potential for future development for the field testing. Sound attenuation was highest in 2500 Hz and 3150 Hz octave frequency bands. Depending on the louvred barrier setup, sound attenuation was up to 28 dB(A) in mentioned frequency bands. The equivalent sound pressure level reduced up to 17 dB(A). The results showed that an increase in the louvre blade angle increases sound attenuation and increases airflow resistance.

Modern world is exposed to various environmental concerns which are closely related to human health condition. Since the automatization, world became vulnerable to the noise and the waste amounts generated. World Health Organization report states, due to noise, Western Europe each year loses approximately 1 million of healthy life years. However, noise is not the only concern. Tyres, since they were banned from the landfills, became enormous problem in a modern society. Approximately 2.6 million tonnes of tyres are generated each year in Europe, out of which 320 000 tonnes of Recycled Tyre Textile Fibre (RTTF) waste. Practically, rubber granules and metals extracted from tyre can be reused, however reusing RTTF is a challenge. The main focus is on the possibility of reuse of RTTF in buildings for acoustical comfort improvement. The determination of sound absorption is implemented by experimental research, based on ISO 10534 standard, involving five types of sound absorbing materials. It was concluded that RTTF has a great potential in use for sound absorption structures and can be an alternative substitute to non-renewable and non-recyclable materials.

Traffic-calming measures act as the instruments to reduce the speed of vehicles. They make a major contribution to road safety; however, on the other hand, air pollution is more likely to occur due to the fact that motor vehicles use brakes and accelerate more frequently. The study reviewed two types of traffic-calming devices, that is, trapezoid-shaped speed humps made of asphalt and plastic circular speed bumps. The obtained results showed an increase in the concentrations of NO, NO2 and CO found in the pollutants emitted from the vehicles approaching speed bumps/humps compared to the concentrations of the same types of pollutants at the check points. As for trapezoidal speed humps, the concentration of nitrogen dioxide increased on average by 1.8 times, that of nitrogen monoxide by 4.3 times and that of carbon monoxide by 2.2 times. Meanwhile, the concentration of nitrogen dioxide at circular plastic speed bumps rose on average by 2.5 times, that of nitric monoxide by 5.0 times and that of carbon monoxide by 3.2 times.

Studies on recycled materials emerged during recent years. This paper investigates samples&rsquo, sound absorption properties for panels fabricated of a mixture of paper sludge (PS) and clay mixture. PS was the core material. The sound absorption was measured. We also consider the influence of an air gap between panels and rigid backing. Different air gaps (50, 100, 150, 200 mm) simulate existing acoustic panel systems. Finally, the PS and clay composite panel sound absorption coefficients are compared to those for a typical commercial absorptive ceiling panel. The average sound absorption coefficient of PS-clay composite panels (&alpha, avg. in the frequency range from 250 to 1600 Hz) was up to 0.55. The resulting average sound absorption coefficient of panels made of recycled (but unfinished) materials is even somewhat higher than for the finished commercial (finished) acoustic panel (&alpha, avg. = 0.51).

Paper sludge is the water treatment waste, which produced during paper production. Paper sludge (PS) waste utilization is the common problem in the EU and internationally. According to authors Frias et al. paper sludge is the main waste in the paper processing factories, the percentage reach 35% of product volume. According to the waste management directive No. 2008/98/EC, paper sludge waste should not be utilised in landfills. Such legislation generates the motivation of this study. This study deals with paper sludge as sound absorbing material. In this paper panels made of paper sludge is studied. Sound absorption coefficient of the panels predicted with Horoshenkov and Swift acoustic model for granular media. The aim of this paper is to predict sound absorption coefficient using non-acoustic parameters of the material. DOI: https://doi.org/10.3846/enviro.2020.820

Reverberacijos trukmė yra viena svarbiausių patalpos akustinių savybių. Ilgas reverberacijos laikas patalpose neigiamai veikia kalbos supratimą, trukdo susikaupti ir t. t. Sumažinus aidėjimo laiką ne tik pagerinamos patalpos akustinės savybės, bet ir pagerinama žmogaus fizinė bei emocinė būsena. Augant vartojimui ir atliekų kiekiams, iškyla atliekų tvarkymo problema. Mus supa elektros įrenginiai, kurių, nors ir ilgai naudojamų iki jiems tampant atlieka, kiekiai nesustoja augti. Ši medžiaga gaminama iš neatsinaujinančių gamtos išteklių, todėl pakartotinis jų panaudojimas ir perdirbimas tampa dar svarbesnis. Tyrimo metu sukurtos skirtingų aukščių – 2 cm, 3 cm, 5 cm ir 10 cm konstrukcijos panaudojant dvigyslius (3,64×5,28 mm), trigyslius (6,42 mm) bei penkiagyslius (9,6 mm) tuščiavidurius kabelius. Išmatuota reverberacijos trukmė mažo tūrio aidėjimo kameroje su skirtingomis konstrukcijomis. Nustatyta aidėjimo trukmės priklausomybė nuo konstrukcijai pagaminti naudojamų kabelių skersmens ir ilgio. Rezultatai parodė, kad 10 cm konstrukcija iš 6,42 mm tuščiavidurių kabelių aukštuose dažniuose nuo 1000 Hz gali sumažinti aidėjimo laiką kameroje iki 48 %. Sukurtos konstrukcijos pagal garso sugerties koeficientus aS atitinka D/E garso sugerties klases.

Popieriaus gamybos dumblas – tai popieriaus pramonės įmonėse susidarančios nuotekų valymo atliekos. Šioms atliekoms tvarkyti skiriama vis daugiau dėmesio, todėl mokslininkai ieško būdų, kaip efektyviau galima būtų jas panaudoti. Kuriant naujas ir tobulinant esamas garsą sugeriančias medžiagas, yra nuolat vykdomi moksliniai tyrimai. Šiomis dienomis ypač kreipiamas dėmesys į natūralias ar pakartotinai naudotinas medžiagas, kurios galėtų būti modifikuotos kaip garsą sugeriančios medžiagos. Viena iš porėtų medžiagų rūšių yra granuliuotos medžiagos. Granuliuotų porėtų medžiagų garso sugerties (α) prognozavimas atliekamas fizikiniais skaitiniais Horoshenkov ir Swift, Champoux-Allard modeliais. Šiems modeliams reikalingi eksperimentinių orinės varžos tyrimų rezultatai. Šiame darbe atliktas trijų skirtingų granuliuotų medžiagų: deginto molio, popieriaus gamybos dumblo ir gumos granulių orinės varžos palyginimas, esant vienodam granulių dalelių dydžiui. Gauti duomenys rodo, kad didžiausia orinė varža, palyginti su kitomis tirtosiomis medžiagomis, yra popieriaus gamybos dumble (4,1 K Pa s/m2). Tokių medžiagų garso sugerties koeficientas α esant 10 cm storio mėginiui siekia 0,57–0,82.

The factors and sources of noise are constantly investigated, as well as the methods of reduction that can help prevent noise pollution. According to ISO 1996-2 taking into account the position of the noise measurement, distance, meteorological and environmental conditions. The aim of the work is to evaluate the dependence and the propagation of noise in the environment caused by train traffic, which depends on different types of sleepers. The results showed that the stretch with wooden sleepers was "quieter" at 3 dB than the section with concrete sleepers, in the sections were measurements was taken: Senieji Trakai-Rudiskes (section with concrete sleepers) and Rudiskes-Matuizos (section with wooden sleepers). The measurements carried out throughout the study showed that the fixed passage noise of the trains falls into the low frequency noise level (31.5–400 Hz).

Urban noise pollution has increased during last decades due to urbanization, increase of vehicles and has significant impact on the quality of life and public health. Sound absorption in enclosure buildings is one of the main topics for researchers which leads to safer environment in public buildings, workplaces, shopping centers and similar buildings due to their high noise levels. For sound control in these environments, perforated panels are being widely used because of their sound absorption properties. This research investigates the acoustic properties of perforated panels, it also includes Zorba modelling program which allows to obtain the acoustic impedance and absorption coefficient of the panels. The use of these panels perforated with circular holes, slats and slots is reviewed.

In the present study, we aimed to determine the changes of indoor radon concentrations depending on various environmental parameters, such as the outdoor temperature, relative humidity, and air pressure, in university building premises of different applications and heights. The environmental parameters and indoor radon concentrations in four different premises were measured each working day over an eight-month period. The results showed that the indoor radon levels strongly depended on the outside temperature and outside relative humidity, whereas the weakest correlations were found between the indoor radon levels and indoor and outdoor air pressures. The obtained indoor radon concentration and environmental condition correlations were different for the different premises of the building. That is, in two premises where the ventilation effect through unintentional air leakage points prevailed in winter, positive correlations between the radon concentration and outside temperature were obtained, reaching the values of 0.94 and 0.92, respectively. In premises with better airtightness, negative correlations (R = &minus, 0.96 and R = &minus, 0.62) between the radon concentrations and outside temperature were obtained. The results revealed that high quality air isolation in premises could be an important factor for higher indoor radon levels during summer compared to winter.

Biochar as a filtering media has been attracted increasing attention for applications in urban storm-water runoff (USWR) management. Up-flow percolation tests were conducted with pine bark (PB) and biochars from PB (BCPB) for evaluating changes in dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) concentrations varying with pyrolysis temperatures (i.e., 300, 450, and 700 °C) and types of USWR (i.e., roof and pathway USWR). The most suitable pyrolysis temperature for limiting DOC leaching from BCPB depends on the types of USWR. For all the adopted pyrolysis temperature, BCPB released cumulative amount of DOC up to 0.01% of the TC content in the up-flow percolation tests with pathway USWR. High-temperature (i.e., 700 °C) BCPB released lower cumulative amount of DOC (up to 0.02% of the TC content) compared to the low-temperature (

Speed table is an artificial road (street) surface irregularity, which is used to reduce speed of road traffic or maintain allowed speed limit in road (street) section. These measures are used to reduce risk for pedestrians by reducing speed of passing vehicles. Before speed table, vehicles usually reduce speed, after passing it, vehicles usually increase their speed and this could increase traffic noise. Measurements were carried out during the day time in L. Asanavičiūtės Street 5, Vilnius. Measurements were divided into two parts, inside the residential apartment building and in its environment. Near the speed table recorded sound level was 69 dB, inside the residential apartment building noise level was approximately 41 dB. In this paper speed table influence on traffic noise propagation in residential area is investigated. Santrauka Greičio mažinimo priemonė – dirbtinis kelio (gatvės) dangos nelygumas, skirtas transporto priemonių greičiui sumažinti arba leistinam greičiui palaikyti kelio (gatvės) ruože. Šių įrenginių paskirtis yra sumažinti pavojų pėstiesiems mažinant važiuojančių automobilių greitį. Automobiliai prieš greičio mažinimo priemonę greitį sumažina, pervažiavę ją, dažniausiai vėl didina greitį, todėl transporto keliamas triukšmas gali padidėti. Tyrimai buvo atlikti dienos metu L. Asanavičiūtės g. 5, Vilniuje. Tyrimai buvo išskirti į dvi dalis: tyrimai gyvenamojo pastato viduje ir tyrimai gyvenamojo pastato aplinkoje. Triukšmo lygis prie vertikaliosios trapecinės greičio mažinimo priemonės buvo 69 dB, tiriamojo gyvenamojo pastato viduje apie 41 dB. Šiame straipsnyje yra nagrinėjama greičio vertikaliosios trapecinės greičio mažinimo priemonės įtaka transporto keliamo triukšmo sklaidai į gyvenamąją aplinką. Reikšminiai žodžiai:transporto triukšmas, vertikalioji trapecinė greičio mažinimo priemonė, gyvenamoji aplinka.