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The Croatian National Health Care Act defines the areas of activities of the public health institute, including the activities of the epidemiology of infectious diseases and chronic non-communicable diseases, public health, health promotion, environmental health, microbiology, school and adolescent medicine, mental health and addiction prevention at Zagreb City level. This paper reviews the highly variable activities in the Andrija Štampar Teaching Institute of Public Health with the aim of promoting a comprehensive approach to the COVID-19 pandemic. Human and analytical resources in the Institute, activities and rapid implementation of innovations testify to the high capacities for adaptation to emerging risks. In the Institute, it is possible to carry out a whole range of tests and to monitor the environmental factors with predominant impact on human health and safety of the Zagreb environment. The supply of safe water for human consumption in the Republic of Croatia during the current COVID-19 crisis has been uninterrupted and in accordance with applicable legislation. Also, our laboratories have been developing and introducing a method for wastewater testing for SARS-CoV-2 presence. The sludge from wastewater treatment plants is used in agriculture, and potential risks associated with the COVID-19 outbreak should be assessed prior to each application on the soil. Increased use of disinfectants during the epidemic may present a higher risk to the aquatic environment. Air quality monitoring indicates a positive impact on air quality as result of isolation measures.

The majority of tourists visit Croatia during the summer months, which overlaps with the ragweed pollination season, and this might be the main health issue, which could affect Croatian tourism. Therefore, the aim of this research was to perform the preliminary analyses of ragweed pollen seasons in two different Croatian tourist cities - continental Zagreb and Mediterranean Zadar, and to define researched areas according to the allergenic risk assessment. The research was performed during a ten year period (2008- 2017), and aerobiological samplings, as well as qualitative and quantitative analyses, were carried out by standard methodology recommended by EAN/REA. The results showed differences between cities in the seasonal pollen integral (SPIn) and intradiurnal variations index (IDI) of ragweed pollen, and similarities in the features of the main pollen seasons (MPS). The SPIn was higher in the air of Zagreb during the whole studied period ; it was on average 2899 pg/m3 in Zagreb, and 579pg/m3 in Zadar. The MPS in both cities were similar (from the first half of August until the mid-September) and relatively short, around 40 days. The IDI indicates that Ambrosia pollen in Zagreb derives from local sources, whilst in Zadar is probably a result of long range transport. According to the allergenic risk assessment, Zagreb is placed in the intermediate risk area, and Zadar in the low risk area. Relatively short exposure times during the summer periods enable both cities to be favourable tourist destinations even during the ragweed seasons, especially Zadar, with its low ragweed pollen concentrations.

The aim of this study was to investigate aerobiological dynamics of pollen in the Mediterranean part of Croatia in the air of the city of Split. Pollen monitoring during the period from 2005 to 2013 was performed using a Hirst-type volumetric trap. Among the identified pollen of 50 taxa, 21 were allergenic. The average annual pollen index was 33513. Three pollination seasons were established: early winter season dominated by tree pollen, spring-summer season dominated by herbaceous plants and summer-autumn season with lower amounts of Parietaria and Cupressaceae pollen. According to the abundance, the main taxa were: Cupressaceae, Parietaria/Urtica, Pinus, Quercus, Olea, Carpinus/Ostrya, Poaceae, Platanus and Ambrosia. The annual pollen index together with the daily maximum concentrations showed an upward trend for selected taxa during the study period. The higest monthly pollen index and the highest biodiversity were recorded in April and the lowest during the late autumn and winter months. The pollen calendar created for the city of Split confirmed Mediterranean features of the pollen spectrum. The longest pollen seasons were recorded for Cupressaceae, Parietaria/Urtica and Poaceae pollen types. The correlations between pollen concentrations and meteorological parameters were analyzed. The correlations between pollen concentrations and temperature were positive, whilst the humidity and the precipitation mostly showed negative influence.

Ragweed Pollen Alarm System (R-PAS) has been running since 2014 to provide pollen information for countries in the Pannonian biogeographical region (PBR). The aim of this study was to develop forecast models of the representative aerobiological monitoring stations, identified by analysis based on a neural network computation. Monitoring stations with 7-day Hirst-type pollen trap having 10-year long validated data set of ragweed pollen were selected for the study from the PBR. Variables including forecasted meteorological data, pollen data of the previous days and nearby monitoring stations were used as input of the model. We used the multilayer perceptron model to forecast the pollen concentration. The multilayer perceptron (MLP) is a feedforward artificial neural network. MLP is a data-driven method to forecast the behaviour of complex systems. In our case, it has three layers, one of which is hidden. MLP utilizes a supervised learning technique called backpropagation for training to get better performance. By testing the neural network, we selected different sets of variables to predict pollen levels for the next 3 days in each of the monitoring stations. The predicted pollen level categories (low–medium–high–very high) are shown on isarithmic map. We used the mean square error, mean absolute error and correlation coefficient metrics to show the forecasting system’s performance. The average of the Pearson correlations is around 0.6 but shows big variability (0.13–0.88) among different locations. Model uncertainty is mainly caused by the limitation of the available input data and the variability in ragweed season patterns. Visualization of the results of the neural network forecast on isarithmic maps is a good tool to communicate pollen information to general public in the PBR.

Previous research indicated that airborne ragweed pollen concentrations may be influenced by weather-related factors. Therefore, the object of this work was to examine the variation in daily pollen concentrations during four ragweed pollen seasons (2006–2009) in the highly urban area of Zagreb. Ragweed pollen grains were collected using a Burkard volumetric sampler (N45º49´55ʺ, E15º58ʹ54ʺ). Meteorological data (maximum, minimum and mean temperatures, relative humidity, wind speed, precipitation, atmospheric pressure and irradiance) were related to daily pollen counts during the ragweed pollen season. The ragweed pollen season started around late July in 2007 and 2009, while it started on 15 August in 2006, the year characterized by a cold spring. However, the start dates of the pollen seasons were not related to the accumulation of thermal units. Maximum daily concentration of 363 grains m-3 was detected on 27 August 2008. Total airborne pollen concentrations ranged from 1188 grains m-3 in 2007 to 4384 grains m-3 in the following year, whereas the duration of ragweed pollen season varied from 50 days in 2008 to 72 days in 2007. The peak of the ragweed pollen season varied from 21 days in 2007 to 36 days in 2009 for airborne pollen concentrations ≥20 grains m-3 and from 1 day in 2007 to 20 days in 2008 for airborne pollen concentrations >80 grains m-3. Airborne pollen levels were affected by weather parameters such as temperature, sunshine, relative humidity, precipitation and wind speed in some ragweed pollen seasons in Zagreb, but these responses were inconsistent over the entire investigated period. Our study showed that large year-to-year variations in atmospheric pollen concentrations in Zagreb could not be consistently related to any of the analysed weather parameters.

A 6-models strong European ensemble of Copernicus Atmospheric Monitoring Service (CAMS) was run through the season of 2014 computing the olive pollen dispersion in Europe. The simulations have been compared with observations in 6 countries, members of the European Aeroallergen Network. Analysis was performed for individual models, the ensemble mean and median, and for a dynamically optimized combination of the ensemble members obtained via fusion of the model predictions with observations. The models, generally reproducing the olive season of 2014, showed noticeable deviations from both observations and each other. In particular, the season start was reported too early, by 8 days but for some models the error mounted to almost two weeks. For the season end, the disagreement between the models and the observations varied from a nearly perfect match up to two weeks too late. A series of sensitivity studies performed to understand the origin of the disagreements revealed crucial role of ambient temperature, especially systematic biases in its representation by meteorological models. A simple correction to the heat sum threshold eliminated the season shift but its validity in other years remains to be checked. The short-term features of the concentration time series were reproduced better suggesting that the precipitation events and cold/warm spells, as well as the large-scale transport were represented rather well. Ensemble averaging led to more robust results. The best skill scores were obtained with data fusion, which used the previous-days observations to identify the optimal weighting coefficients of the individual model forecasts. Such combinations were tested for the forecasting period up to 4 days and shown to remain nearly optimal throughout the whole period.

Genetic and environmental factors are responsible for running allergic diseases. The aim of this study was to compare the values of total- (t-IgE) and allergen-specific IgE (s-IgE) to Ambrosia artemisiifolia L. (Amb a) in children with sensitization to Amb a during ragweed pollination season, who experienced seasonal symptoms of allergic rhinitis (rhinorrhea, post-nasal drip, nasal congestion, itching, sneezing) and asthma (coughing, especially at night, wheezing, shortness of breath, chest tightness). Ragweed pollen grains were collected in Virovitica (rural area) and Zagreb (urban area)—cities with the same geographical width and elevation—during ragweed pollination seasons (July–October in 2006 and 2007), and their count was estimated. Concentration of t-IgE and s-IgE in pollination season was determined in serum of children with symptoms of allergic diseases. The total count of ragweed pollen grains (PG) differed significantly between Virovitica and Zagreb in both years, 2006. and 2007. In Virovitica it was significantly greater than in Zagreb. There was no statistically significant seasonal difference in both, t-IgE and s-IgE, respectively. No correlation was found between pollen grain count and the concentration of IgE’s. To clarify the induction of IgE synthesis in children with sensitization to Amb a, further studies are needed.

The aim of this study was to determine the onset, length and end of the ragweed pollen season, taking into account diurnal, day-to-day, monthly and annual pollen variations, the effect of some meteorological parameters on atmospheric pollen concentrations and possible differences in the airborne pollen season and concentration due to sampling site. Airborne pollen was collected at three sites in central Croatia (Zagreb, Samobor and Ivanić Grad) during three pollen seasons (2002– 2004). Seven-day Hirst-type volumetric pollen traps were used for pollen sampling. Ragweed pollen was the third most abundant pollen type to occur in the atmosphere of central Croatia. Total Ambrosia pollen concentration was the highest in the 2003 pollen season and the lowest in 2004 at all sampling sites. Maximum emissions were restricted to August and September. Intradiurnal periodicity showed a peak from 1000 to 1200 hours. The concentration of ragweed pollen during the pollen season was greatly influenced by temperature and precipitation: on rainy days accompanied by temperature decline, the air pollen concentration decreased abruptly. The results of this study are aimed at helping to alleviate the symptoms of allergic reactions in individuals with ragweed pollen hypersensitivity, thus improving their quality of life.

Pollen of grasses (Poaceae) is one of the most important airborne allergen sources worldwide. The aim of the study was to determine diurnal, day‐to‐day, weekly, monthly and annual pollen variation, and the effect of selected meteorological parameters on atmospheric pollen concentrations in Zagreb. A preliminary study was carried out during four seasons (2002 – 2005), using a 7‐day VPPS 2000 Hirst volumetric pollen trap. Total annual grass pollen concentrations in Zagreb were constant (2 673 – 3 074 p.g.m−3), with a relative drop in 2004 (1 196 p.g.m−3). The beginning of the grass pollen season is usually observed when the average daily temperature exceeds 13.5°C (max. daily temp. 19.5°C), without precipitation. In all four study years the absolute peak of concentrations occurs in the second half of May. The length of pollen season during the study period was 157 – 173 days. A high variability was observed in the maximal concentration and in the number of days when grass pollen concentration exceeded the t...

The aim of this study was to construct a picture of the influence of meteorological conditions on the start and duration of the airborne Betulaceae pollen season and the pollen concentrations in the atmosphere of Zagreb, Croatia. The study during three seasons (2002–2004) used a 7‐day Hirst‐type volumetric pollen and spore trap. Total annual airborne pollen of Alnus, Corylus and Betula greatly varied from year to year. The differences in the dates of onset of airborne pollen presence of Alnus, Corylus and Betula noted in Zagreb in 2002–2004 were controlled by weather conditions, particularly temperature and precipitation. In all years studied, airborne pollen peaks were recorded on days with temperature above 0°C and without or minimal precipitation. The mean number of days with airborne pollen concentrations exceeding levels which provoke symptoms of an allergic reaction was 15, 16 and 29 days for alder, hazel and birch, respectively. The results of the present study may provide useful data for allergolo...

We examined the atmospheric conditions favourable to the occurrence of maximum concentrations of ragweed pollen with an extremely high risk of producing allergy. Over the 2002-2009 period, daily pollen data collected in Zagreb were used to identify two periods of high pollen concentration (600 grains/m(3)) for our analysis: period A (3-4 September 2002) and period B (6-7 September 2003). Synoptic conditions in both periods were very similar: Croatia was under the influence of a lower sector high pressure system moving slowly eastward over Eastern Europe. During the 2002-2009 period, this type of weather pattern (on ~ 70% of days), in conjunction with almost non-gradient surface pressure conditions in the area (on ~ 30% of days) characterised days when the daily pollen concentrations were higher than 400 grains/m(3). Numerical experiments using a mesoscale model at fine resolution showed successful multi-day simulations reproducing the local topographic influence on wind flow and in reasonable agreement with available observations. According to the model, the relatively weak synoptic flow (predominantly from the eastern direction) allowed local thermal circulations to develop over Zagreb during both high pollen episodes. Two-hour pollen concentrations and 48-h back-trajectories indicated that regional-range transport of pollen grains from the central Pannonian Plain was the cause of the high pollen concentrations during period A. During period B, the north-westward regional-range transport in Zagreb was supplemented significantly by pronounced horizontal recirculation of pollen grains. This recirculation happened within the diurnal local circulation over the city, causing a late-evening increase in pollen concentration.

Background: Environmental factors play an important role in asthma morbidity, although the contribution of individual pollutants or pollens in exacerbating asthma is not completely elucidated. Despite the evidence of importance of the hornbeam pollen in inducing allergic sensitization, its role in provoking asthma exacerbation has not been evaluated. The aim of the present study was to investigate effects of traffic pollutants on adult asthma hospitalization adjusting for pollens including hornbeam. Methods: During a 3-year period, health and environmental data were collected and analyzed. Daily asthma hospitalizations were regressed on pollutants and potential confounding variables using an autoregressive Poisson model. Results: The risk of asthma hospitalization was associated significantly with the 95th to 99th percentile increase in levels of nitrogen dioxide (RR = 1.22; 95% CI: 1.05–1.40), carbon monoxide (RR = 1.25; 95% CI: 1.01–1.55) and hornbeam pollen (RR = 1.21; 95% CI: 1.11–1.30). The effect of nitrogen dioxide was delayed by 5 days. No statistically significant increase in the risk of asthma hospitalization was found for PM10 particles. A comparison among the standardized regression coefficients and their respective p values indicates that the most important risk factor for asthma hospitalization is associated with hornbeam pollen levels. No statistically significant interactions between pollutants and pollens were detected. Conclusions: The current results suggest that traffic-related air pollution is associated with increased risk of adult asthma hospitalization. Nonetheless, the most significant risk for asthma hospitalization is associated with hornbeam pollen levels in the city of Zagreb.

We present here a simple methodology for calculating species inventories for allergenic pollen that can be used by atmospheric transport models. Ragweed (Ambrosia) species distribution or infection level on the Pannonian Plain has been used as an example of how the methodology can be used. The Pannonian Plain is one of the three main regions in Europe recognized as being polluted by Ambrosia. The methodology relies on spatial variations in annual Ambrosia pollen counts, knowledge on ragweed ecology and detailed land cover information. The results of this analysis showed that some of the highest mean annual ragweed pollen concentrations were witnessed around Kecskemétin central Hungary and Novi Sad in northern Serbia. These areas are also the areas with the highest density of Ambrosia habitats. The resulting inventory can be entered into atmospheric transport models in combination with other components such as a phenological model and a model for daily pollen release, in order to simulate the movement of ragweed pollen from the Pannonian Plain. The methodology is likely to be generally applicable for creating inventories of species distribution of allergenic plants. The main requirement is availability of: detailed land cover information ; pollen indexes ; a list of the most important habitats ; and a region of interest that is mainly influenced by local sources.

Pollen allergy is characterized by seasonal allergic manifestations affecting patients during the plant pollen season. The aim of this study was to analyze the Betulaceae pollen pattern in Zagreb (2002-2005) and to determine the incidence of sensitization to these pollen types in patients with seasonal respiratory allergy. Twenty-four-hour pollen counts were carried out using volumetric procedure. Skin prick test were performed on a total of 864 patients aged 18-80in Zagreb between 2 January-31 December 2004. Pollen of the representatives of the family Betulaceae accounted for a significant proportion of total pollen (34% on an average), predominated by Betula pollen and considerably lower proportion of Alnus sp. and Corylus sp. pollen. Alder and hazel pollen first occurred in the air in February throughout the study period. The highest airborne pollen concentration of these taxa was recorded in February and March. The birch pollen season generally peaked in April. Only 2.67% of patients showed birch pollen monosensitization. The proportion of patients with polysensitization to Betulaceae pollen was considerably greater (12.88%), whereas polysensitization to Betulaceae, Poaceae and Ambrosia pollen was recorded in the highest proportion of patients (26.23%). According to age, the highest and lowest rate of allergy was recorded in the 31-50 and51 age groups, respectively (46.22% vs 23.12%). Female predominance was observed across all age groups. The patients with monosensitization to birch pollen had the most severe symptoms in April. In the patients with poylsensitization to alder, hazel and birch pollen who developed cross-reaction, initial symptoms occurred as early as February, with abrupt exacerbation in March and April. The most severe condition was observed in the patients allergic to birch, hazel, alder, grass and ragweed pollen, with symptoms present throughout the year and exacerbation in spring and late summer months.

In spite of the low atmospheric pollen levels, Artemisia sensitisation and allergy has been reported widely. The aim of the study was to determine the length of pollen season, intradiurnal, daily and monthly pollen variation, and the effect of some meteorological parameters on atmospheric pollen concentrations in Central Croatia. Seven-day Hirst volumetric pollen and spore traps were used for pollen sampling. The Artemisia pollen season lasted from the end of July until the end of September with the highest concentrations in August. The percentage of the total pollen count ranged from 0.52% to 0.92%. The intradiurnal peak occurred between 10 a.m. and 12 a.m. Statistical analysis showed a significant correlations between higher air temperature and high pollen concentration as well as high precipitation and low pollen concentration. Results of this study are expected to help in preventing the symptoms of allergic reaction in individuals with Artemisia pollen hypersensitivity.

The aim of the study was to determine the onset, duration and termination of the ragweed pollen season; intradiurnal, daily and monthly pollen variation, and possible differences in the occurrence and concentration of ragweed pollen according to sampling sites between 2002 and 2003. The study was conducted at three sampling sites in central Croatia over two pollen seasons (2002 and 2003) using the volumetric method of sampling (Hirst type sampler). In 2003, the ragweed pollen season was by 43 % longer and the percentage proportion of ragweed pollen by 3.4 % greater in comparison with 2002. The total ragweed pollen count and number of days with ragweed pollen concentration greater than 30 pollen grains per m (3) air showed a declining tendency from East to West in both seasons. The intradiurnal peak concentration occurred between 10.00-14.00. The air concentration of ragweed pollen decreased with temperature decline and precipitation. Results of the study provided useful information to individuals allergic to ragweed pollen thereby allowing them to adjust their outdoor activities to avoid contact with the allergen.

The aim of the study was to analyse the relationship between meteorological conditions and Alternaria and Cladosporium spore concentrations in the air of Zagreb in August 2002 and August 2003. These months were chosen because they represented climatic extremes. A 7-day VPPS 2000 Hirst volumetric pollen and spore trap was used for spore sampling. Spores marked as 'others' (ascospores, basidiospores, Epicoccum, Ustilago, Pithomyces, Helminthosporium, Stemphylium, Torula, Botrytis, Didymella) were found to have predominated in the month of August in both 2002 and 2003 with 91.1% and 70.5%, respectively. Because of favourable weather conditions (higher air temperature and minimal precipitation) in August 2003, the concentrations of Alternaria and Cladosporium spores were 3.4-fold those recorded in the same month in 2002. Also, the peak daily concentrations of these spores were measured on days without precipitation and with higher air temperature. Intradiuranal variation in the Alternaria and Cladosporium spore concentrations was identical in 2002 and 2003 (lowest in 2-hour interval between 06:00-08:00, and highest between 10:00-12:00). In spite of the three-fold increase in the Cladosporium spore concentration in August 2003, the borderline concentration of 3,000 spores/m3 air that is associated with the occurrence of allergic reactions was only exceeded on a single day. Air concentration of Alternaria spores exceeded borderline value of 100 spores/m3 air on as many as 17 days, suggesting that at that time of the year the risk of allergic reaction was only present in individuals allergic to this spore type.

V. MadžarevicAndrija Mohorovicic Geophysical Institute,DepartmentofGeophysics,FacultyofScience,UniversityofZagreb,Horvatovac 95,10000 Zagreb, Croatiae-mail: telisman@gfz.hrL. SrnecMeteorological and Hydrological Service of Croatia, Zagreb,Croatia,Gric 3,10000 Zagreb, CroatiaR. PeternelUniversity of Applied sciences Velika Gorica,Velika Gorica, CroatiaI. Hrga