Ozone concentration at the ground level of the atmosphere is constantly monitored, but people spend about 90 per cent of their time inside. Therefore, elevated level of ozone in premises is a matter of great concern. High indoor ozone concentration can cause respiratory failure, hacking cough, pain during deep breath, gnawing in breast and sometimes even nausea. According to the Lithuanian hygiene standard HN 35:2002, a marginal ozone concentration of eight hour average in a workplace is 200 μg/m3. Investigation of ozone distribution from its emission source ‐ a copying machine ‐ in a room were caried out. Simulation showed that an equilibrium state, when ozone formation is equal to ozone decay, was observed only in 40 minutes after the emission source was started up in the room. The study of both vertical and horizontal distribution of ozone was analysed. The results showed that an average concentration near the floor varied in the interval 8–22 μg/m3, at the level of the machine it was from 10 to 380 μg/m3, and the interval of concentration was 10–110 μg/m3 at the ceiling. Assessment of ventilation influence on ozone distribution was performed. Ozone concentration varied in the interval 2–815 μg/m3 near the source at a different intensity of copying without ventilation, and using ventilation the concentration decreased up to 0–686 μg/m3. It was established that at 0,5 m distance from a copying machine ozone concentration decreased two times, therefore, a person working with a copying machine should be at a far enough distance from the ozone source in order to reduce its effect on his health.

The indoor ozone and nitrogen oxides concentration depends on their outdoor concentrations, indoor sources and their removal rates on the surfaces. The paper presents experimental data of the of ozone and nitrogen oxide removal in the chamber. The ambient conditions were simulated by four combination of different temperature and relative humidity levels. The impact of temperature (T = 20 °C and T = 30 °C) and relative humidity (RH = 24% and RH = 80%) on the deposition velocity was estimated. It was found that the ozone removal in the chamber was influenced more by temperature, and the nitrogen oxides removal was affected more by relative air humidity. The results showed that higher ambient temperature (T = 30 °C) increased the ozone removal rate in the chamber 3 times on an average, and high relative humidity (RH = 80%) increased the NOx removal rate 4.5 times in comparison with the initial conditions (T = 20 °C; RH = 24%). The obtained deposition velocities varied in the range (0.0045–0.0137) cm s−1 for ozone and in the range (0.002-0.0129) cm s −1 for nitrogen dioxide. Santrauka Ozono ir azoto oksidų koncentracija patalpose priklauso nuo šių teršalų koncentracijos lauke, jų šaltinių patalpose ir šių teršalų suirimo greičio ant skirtingų paviršių. Darbe nagrinėjamas ozono ir azoto oksidų suirimas eksperimentinėje kameroje. Skirtingos mikroklimatinės sąlygos buvo sukuriamos naudojant keturių skirtingų temperatūrų ir santykinių oro drėgnių lygių derinius. Vertinta temperatūros (T = 20 °C ir T = 30 °C) ir santykinio drėgnio (RH = 24 % ir RH = 80 %) įtaka tiriamų teršalų suirimui. Nustatyta, kad ozono suirimui daugiau įtakos turėjo temperatūra, o NOX irimui – santykinis oro drėgnis. Nustatyta, kad aukštesnė aplinkos temperatūra (T = 30 °C) paspartina ozono suirimą kameroje vidutiniškai tris kartus, o didelis santykinis drėgnis (RH = 80 %) paspartina NOX suirimą 4,5 karto, lyginant su pradinėmis sąlygomis (T = 20 °C; RH = 24 %). Eksperimento metu ozono suirimo greitis kito nuo 0,0045 iki 0,0137 cm s−1, o azoto oksidų – nuo 0,002 iki 0,0129 cm s−1. Резюме Концентрации озона и оксидов азота в помещениях зависят от их концентрации в открытом воздухе, источникахвнутри помещений и скорости их распада на поверхностях. В статье представлены экспериментальные данные по распаду озона и оксидов азота в камере при разных микроклиматических условиях, созданных с применением четырех комбинаций температур и относительной влажности. Оценивалось воздействие температуры (T = 20 °С и Т = 30 °С) и относительной влажности воздуха (RH = 24% и RH = 80%) на скорость осаждения. Было обнаружено,что на распад озона в камере большее влияние оказывает температура, а на распад оксидов азота – относительная влажность воздуха. Результаты показали, что при повышении температуры окружающей среды (T = 30 °С) увеличилась скорость распада озона в камере в 3 раза по сравнению со средней, а при высокой относительной влажности (RH = 80%) увеличилась скорость распада NOx в 4,5 раза по сравнению с начальными условиями (T = 20 °C; RH = 24%). Полученные для озона скорости осаждения варьировали в пределах (0,0045−0,0137) cм с-1, а для оксида азота – в пределах (0,002−0,0129) cм с-1.

The method of applying passive diffusive samplers for research on air quality is simple, easy enough and requires no electricity. The operating principle of almost all passive samplers is based on chemical reactions taking place on absorbent (impregnated filter or grid). The pollutant absorption mechanism is based on passive diffusion through the gas diffusion layer to absorbent. The diffusion process can be explained by first Fick’s law described as a free movement of gases from the ambient air to a passive sampler. This movement depends on pollutant gradient. The aim of this paper is to analyse the influence of an impregnating solution on the efficiency of diffusive samplers. The object of the study covers the triethanolamine (TEA) aqueous solutions of 5%, 10%, 20%, 30% and 50%. The results obtained showed that 30% and 50% aqueous solution gave 68% and 89% relative error making the true meaning of the oxides of nitrogen analyzer testimony. Data on the passive samplers impregnated with TEA aqueous solutions having concentrations of 5%, 10% and 20% are within definite 25% uncertainty established by the European Union Directives.

Abstract. Based on statistical analysis indicating the dependence of the number of road traffic accidents on driving experience, a mathematical model of such correlation is offered. The mathematical model has been tested generating a new approximation using the eigenfunctions of the introduced model applied to draw long-term forecasts for the dependence of the number of potential road accidents on driving experience. Since we have more road traffic accidents per one hundred thousand inhabitants than other EU countries, comprehensive data analysis might also be useful for the EU community.

This paper presents a set of data obtained in experimental and theoretical studies of the indoor ozone concentration with displacement of the ozone source. The measurements were conducted for three typical room configurations. The simulation takes into account actual room sizes and deposition rates on the surface material to predict the indoor ozone concentration. Both experimental and simulated results suggest that the air exchange rate and the material surface in the room play a significant role in determining ozone levels in indoor environments. The simulated indoor ozone concentration was compared with experimental results (correlation r = 0.8), and the accuracy of the model was tested.