We investigated the influence of local meteorological conditions and number of visitors on ambient particulate matter (PM) mass concentrations and particle fraction ratios at the Plitvice Lakes ...National Park between July and October 2018. Outdoor mass concentrations of particles with aerodynamic diameters of less than 1, 2.5, and 10 μm (PM
, PM
, and PM
, respectively) and indoor PM
were measured with two light-scattering laser photometers set up near the largest and most visited Kozjak Lake. Our findings suggest that the particles mainly originated from background sources, although some came from local anthropogenic activities. More specifically, increases in both indoor and outdoor mass concentrations coincided with the increase in the number of visitors. Indoor PM
concentrations also increased with increase in outdoor air temperature, while outdoor PMs exhibited U-shaped dependence (i.e., concentrations increased only at higher outdoor air temperatures). This behaviour and the decrease in the PM
/PM
ratio with higher temperatures suggests that the production and growth of particles is influenced by photochemical reactions. The obtained spectra also pointed to a daily but not to weekly periodicity of PM levels.
Air quality monitoring traditionally relies on ground stations and satellites, which may face limitations in capturing real-time data near pollution sources due to site complexity or physical ...barriers. To overcome these challenges, unmanned aerial vehicles (UAVs) equipped with air quality sensors offer new opportunities for comprehensive and rapid data collection in urban and industrial areas. In this study, we propose a novel approach by utilizing a UAV-based system to investigate the spatial distribution of particulate matter in the atmosphere. The monitoring site is strategically located at an intersection in Zagreb, known for its medium to high traffic density and its suitability for capturing the impact of vehicular emissions on air quality. It is essential to note that this assumption based on the observed conditions is not a precisely measured figure but rather an estimate based on observations and the context of the road. Traffic density may vary throughout the day, week, or year, depending on working hours, events, seasonal factors, and other influences affecting vehicular movement. The UAV is equipped with lightweight and low-cost sensors specifically designed for measuring airborne particles, ensuring accurate and reliable measurements. These sensors, integrated onto the UAV and placed on the upper side, minimize interference from propeller-generated airflow and turbulence, providing representative assessments of air quality conditions. By collecting precise data on the concentration of airborne particles, including PM1, PM2.5, and PM10, the study aims to gain insights into the spatial distribution of pollutants near the intersection and understand the potential impacts of traffic emissions on the surrounding environment. Additionally, the UAV's sensors can connect to smartphones or computers, enabling real-time data viewing and analysis, facilitating prompt adjustments and informed decision-making based on the current air quality conditions. The findings challenge the initial assumption as the concentration of particles does not decrease with increasing altitude, requiring further research to understand this phenomenon. Furthermore, future research will consider integrating meteorological data, such as temperature, humidity, air pressure, wind direction, and speed, from a nearby weather station. By analyzing the interplay between meteorological parameters and particle concentration, a comprehensive understanding of airborne particle dynamics can be achieved. This approach will contribute to the development of effective strategies for managing air quality, considering the complex interdependencies and factors influencing particle distribution in the air.
Plaster splints are used daily in surgical and orthopedic fields in order to immobilize injured children and adults. The aim of this study was to measure the aerodynamic diameter and concentration of ...dust particles in the air caused by sawing plaster splints (calcium sulfate dehy-drate). We performed fractional measurements of airborne dust particles. The measured particles, which can potentially be inhaled, may have a specific negative effect on human health. Measurements were conducted in laboratory research facilities that simulated hospital conditions within a casting room and the associated waiting room. Measurements within the casting room were made using two particle collector devices and one laser photometer. The measurement for the simulated waiting room was performed using the same principles and devices. The collected plaster dust particles differed in aerodynamic diameter and concentration according to the various locations observed. The highest concentration of particles of all sizes was recorded at the site of cast sawing. There was direct correlation between distance from the source and concentration of airborne particles; this concentration was lowest in the waiting room. The concentrations of plaster dust recorded were lower than the recommended minimal limit values for total and respiratory fractions in Croatia. Accordingly, it can be assumed that sawing of plaster splints has no harmful health effects on the exposed patients and health personnel.
We investigate the interaction of the synoptically forced southeastward Etesian winds with small-scale, thermally induced sea-land breezes (SLB) during two multiday summertime periods over the ...Adriatic. Synoptic conditions favorable for the simultaneous establishment of these two airflows are characterized by weak large-scale forcing and fair weather conditions over the area of interest. We analyze both measured and modeled surface air temperature and wind data. Measuring sites were selected so as to cover the northern, eastern and western Adriatic coast, as well as one offshore and one open-sea location. Modeled fields were obtained from the operational hydrostatic mesoscale meteorological model ALADIN at a horizontal resolution of 8 km. In addition, modeled wind fields were dynamically adapted to a resolution of 2 km. We show that the model at the current operational horizontal resolution of 8 km reproduces reasonably well the surface airflow over the Adriatic. Further, the finer horizontal resolution results in similar wind fields, except for occasional, somewhat stronger winds (up to about 2–3 m s
−
1
) that were found downstream of several topographically complex regions along the eastern coast. The air temperature, however, is not well reproduced for the open-sea site (Palagruža, P) or the coastal site (Brindisi, Br), compared to the other coastal sites, due to its specific location, which is more exposed to the effects of large water bodies. The results also reveal salient differences in airflow above the eastern and western Adriatic, caused by the different topographic setups of the two coasts. Specifically, in summer above the eastern and western Adriatic, sea-land breezes and the Etesians dominate, respectively. Along the eastern coast, the sea-land breezes are enhanced by additional topographic forcing and channeling effects, while along the western coast they are weaker and mainly found only above the land. Further, results suggest several noticeable, region-specific airflow features that seem to be typical for summertime fair weather conditions over the Adriatic. During the daytime, these are: 1) a pronounced divergence above the northern Adriatic; 2) very strong winds west of Montenegrin and the Albanian coast; and 3) enhanced winds above the central portion of the eastern coastal area. At night, 4) topographically-induced jets along the eastern coast are typical, while the entire day is characterized by 5) elevated wind speeds adjacent to the Gargano Peninsula. Both the differences between the eastern and western Adriatic and the occurrence of the above region-specific features can be attributed to the topographic setup and consequent slope flows and airflow channeling.
Enhanced sea level oscillations with devastating effects occurred on 26/27 June 2003 in the east Adriatic. The phenomenon was recognized as a resonantly coupled air‐sea interaction, where the sea ...wave is forced by the propagating atmospheric pressure disturbance. This study examines the dynamics and predictability of the atmospheric component of the coupled system. First, the initiation, amplification and maintenance of the system are examined. The source of the perturbation is traced back to the Alpine region, where the potentially unstable air in the westerly current lifts over the Alps resulting in convection and wave development. The wave and convective activity apparently couple in a wave‐CISK manner and propagate southeastward down the eastern Adriatic coast. Due to the potentially unstable air above the Adriatic, the system additionally amplifies along its track. The dissipation of the system occurs after the landfall. Second, the performance of the numerical model at the resolution that is similar to operational NWP model resolution is examined. This severe event is highly susceptible to the details of the model configuration, presumably due to the sensitivity in coupling of the wave and MCS. Thus although the model is able to reproduce and forecast this kind of event at a fairly coarse resolution, the details of the spatial structure, as well as the time of onset, are questionable. In this case, the greatest sensitivity is primarily in the treatment of moist and convective processes.
The new method for the forecasting hourly concentrations of air pollutants is presented in the paper. The method was developed for a site in urban residential area in city of Zagreb, Croatia, for ...four air pollutants (NO
2, O
3, CO and PM
10). Meteorological variables and concentrations of the respective pollutant were taken as predictors. A novel approach, based on families of univariate regression models, was employed in selecting the averaging intervals for input variables. For each variable and each averaging period between 1 and 97 h, a separate model was built. By inspecting values of the coefficient of correlation between measured and modelled concentrations, optimal averaging periods for each variable were selected. A new dataset for building the forecasting model was then calculated as temporal moving averages (running means) of former variables. A multi-layer perceptron type of neural networks is used as the forecasting model. Index of agreement, calculated for the entire dataset including the data for model building, ranged from 0.91 to 0.97 for the respective pollutants. As suggested by the analysis of the relative importance of the input variables, different agreements for different pollutants are likely due to different sources and production mechanisms of investigated pollutants. A comparison of the new method with more traditional method, which takes hourly averages of the forecast hour as input variables, showed similar or better performance. The model was developed for the purpose of public-health-oriented air quality forecasting, aiming to use a numerical weather forecast model for the prediction of the part of input data yet unknown at the forecasting time. It is to expect that longer term averages used as inputs in the proposed method will contribute to smaller input errors and the greater accuracy of the model.
ABSTRACT
The influence of mesoscale flow on the elevated O3 concentrations recorded during 13–19 August 2000 in the coastal town of Rijeka (45.33°N, 14.45°E) has been examined. Although high levels ...of ozone concentration are often observed there, this episode was unique due to hourly afternoon concentrations persistently higher than 180 µg m−3 and nocturnal levels above 100 µg m−3. To study this episode, available meteorological and ozone measurements were analysed, along with supplemental numerical simulations and trajectories. The measurements revealed favourable atmospheric conditions for the production of ozone, i.e., high air temperatures associated with (1) the exchange of two dominant (although relatively weak) large‐scale flows: southwesterly versus northeasterly bora winds, and (2) local thermal circulation. The bora wind was relatively weak and short lasting. Although the bora transported the polluted air mass away along the western Adriatic coast, the southwesterly flow returned ozone‐rich air toward the Alps, thus contributing to the overall pollution over the northern Adriatic Sea. Models revealed the superposition of the southwesterly wind and local, thermally induced winds that caused the regional transport of ozone toward the Alps and the eastern Adriatic coast. However, while the regional transport of ozone from the northern Adriatic was found to enhance somewhat the ozone concentrations in Rijeka at the end of period studied, its surrounding local emission sources, uniform local thermal circulation systems, and recirculation of pollutants were crucial factors in the formation of the large daytime and night time ozone levels observed in Rijeka.
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