Publications by authors named "Iva Hůnová"

19 Publications

  • Page 1 of 1

Terrain and its effects on fog occurrence.

Sci Total Environ 2021 May 28;768:144359. Epub 2020 Dec 28.

Institute of Computer Science of the Czech Academy of Sciences, Pod Vodarenskou vezi 2, 182 07 Prague 8, Czech Republic.

Fog is a very complex phenomenon, relevant to both atmospheric physics and chemistry, contributing to the atmospheric inputs of both nutrients and pollutants to the environment. Fog occurrence is affected by numerous factors. The aim of this study is to examine the effects of terrain on fog occurrence. Namely, we studied in detail how altitude, slope and landform influence the probability of fog occurrence using the generalized additive model. In particular, we investigated how different explanatory variables might modify (deform) the trend and the seasonal component of the probability of fog occurrence. We used long-term records of daily fog occurrence measured in 1981-2017 at 56 professional meteorological stations in Romania, reflecting different environments and geographical areas. The altitude of the sites under review ranged between 13 and 2504 m above sea level, the coverage of localities at different altitudes being highly uneven. Out of the terrain variables considered, the most decisive influence was found to be altitude. We have included information on slope and landform, which refined and bettered the basic model. Our model results indicated a significant decrease in the probability of fog occurrence over the examined period. The behaviour of fog differed according to the altitude, the most profound effects being observed for ground-level fog and fog above flat terrain. The probability of fog occurrence at different altitudes varied mostly in summer and autumn, whereas it was very similar in winter.
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http://dx.doi.org/10.1016/j.scitotenv.2020.144359DOI Listing
May 2021

Trends in ambient O concentrations at twelve sites in the Czech Republic over the past three decades: Close inspection of development.

Sci Total Environ 2020 Dec 19;746:141038. Epub 2020 Jul 19.

Institute of Computer Science of the Czech Academy of Sciences, Pod Vodarenskou vezi 2, 182 07 Prague 8, Czech Republic; National Institute of Public Health, Srobarova 48, 100 42 Prague 10, Czech Republic. Electronic address:

Ambient or ground-level ozone (O), a key player in atmospheric chemistry, has been studied extensively throughout the world in recent decades due to its harmful effects on human health and the environment. The aim of this study is to examine in detail the time patterns of O in the Czech Republic, a Central European country with a long-term history of ambient air pollution. We have examined the interplay between annual trends and within-a-year seasonality in daily O concentrations at twelve stations representing different environments, geographical regions and altitudes in the Czech Republic in 1993-2018. We base our analysis on a generalised additive model (GAM) framework as a modern regression approach suitable for addressing non-linear trend shapes in a formalised and unified way. In particular, we use penalised splines. The inconsistent behaviour of the stations prior to 1998, two local maxima around 2003 and 2006 and a steady increase in O at all sites from 2014 to the present are the main features of our study. A seasonality O pattern with a clear maximum in May-June is similar for all stations. In parallel with the O concentration changes over the years, the deformation of seasonality profiles over a long period of time occurs, resulting in a shift of the peak O concentrations towards later days in the year. Our statistical modelling offers a detailed view of both long-term trend and seasonality components separately. Additionally, in a model with trend*seasonality interaction, we are able to study the gradual deformation of the seasonality profile over the years. Capsule: Our analysis of daily mean O concentrations at twelve Czech sites in 1993-2018 revealed a steady increase in O from 2014 and deformation of the seasonality O profiles over the year.
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http://dx.doi.org/10.1016/j.scitotenv.2020.141038DOI Listing
December 2020

Long-term trends in fog occurrence in the Czech Republic, Central Europe.

Sci Total Environ 2020 Apr 6;711:135018. Epub 2019 Nov 6.

Meteorology and Climatology Department, Czech Hydrometeorological Institute, Prague, Czech Republic.

Fog is a very important and complex atmospheric phenomenon of the utmost importance for the environment and for human society. For practical reasons, fog occurrence is observed regularly at meteorological stations worldwide. Decreasing trends in fog frequency reported from numerous regions have been often associated with either decreasing pollution or climate change, including increasing temperature and changes in atmospheric circulation. We have examined the data on fog occurrence from twelve Czech sites representing different environments (urban, rural, mountain), geographical areas, and altitudes across the country. For our analysis we used long-term records from the time period of 1961-2018, covering both the ambient air's heavily polluted periods of the 1970s and 1980s and the cleaner period, following the adoption of new, more stringent legislation and effective countermeasures after the 1990s. We applied a generalised additive model (GAM) framework as a flexible, semiparametric regression approach to address nonlinear trend shapes in a formalised and unified way. In particular, we employed a penalised spline approach with cross-validated penalty coefficient estimation. Our study confirmed non-linear behaviour for both year-to-year trends and annual seasonality. Our results showed further that over the analysed, almost sixty-year period, fog occurrence has decreased significantly at all the examined sites, though the pattern of the long-term change differed among individual sites. Moreover, we have found significant seasonality in fog occurrence, though it is different at individual sites. Furthermore, apart from the overall annual fog probability change over the years, at some sites the fog's seasonal profile has also deformed substantially over the long term.
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http://dx.doi.org/10.1016/j.scitotenv.2019.135018DOI Listing
April 2020

Long-term trends in nitrogen oxides at different types of monitoring stations in the Czech Republic.

Sci Total Environ 2020 Jan 10;699:134378. Epub 2019 Sep 10.

Czech Hydrometeorological Institute, Na Sabatce 17, 143 06 Prague 4 - Komorany, Czech Republic.

Nitrogen oxides (NO) are important in atmospheric chemistry and have substantial environmental impacts. This study provides a detailed data analysis on long-term changes in ambient NO levels within the framework of their emission pattern. We examined the trends in NO, NO, NO and NO/NO ratio at 39 Czech sites representing different environments (urban, rural, mountain, industrial) in 1994-2016, i.e. a 23-year time series, using the non-parametric Man-Kendall test. The ambient air concentrations in NO, NO and NO decreased significantly at most of the sites, as was assumed due to the substantial NO emission decrease over the period under review. The largest decrease per year was detected at the urban site in capital Prague (decrease in the 98 percentile equal to 2.28 ppb, decrease in the annual median equal to 1.00 ppb). At some sites, however we observed a substantial equivocal temporal change in the NO/NO ratio. Whereas at some sites the NO/NO ratio was decreasing, at other sites the trend was increasing significantly. The highest increase per year in the annual median of the NO/NO ratio, equal to 0.0086 was detected at the urban Praha 1-nám-Rep. site; the highest increase per year in the 98 percentile, equal to 0.0126 was recorded at the rural Krupka site. Most sites (regardless of type) with generally increasing trends in the NO/NO ratio, are situated in the north-west portion of the Czech Republic The increasing NO/NO ratio detected at some sites is believed to implicate undesired changes in atmospheric chemistry, namely with respect to ambient O formation, promoting increasing O concentrations.
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http://dx.doi.org/10.1016/j.scitotenv.2019.134378DOI Listing
January 2020

Assessment of air pollution origin based on year-long parallel measurement of PM and PM at two suburban sites in Prague, Czech Republic.

Sci Total Environ 2019 May 1;664:1107-1116. Epub 2019 Feb 1.

Czech Hydrometeorological Institute, Na Šabatce 17, 143 06 Prague 4, Czech Republic.

From 2nd April 2008 to 28th March 2009, a total 248 daily samples of the PM and PM were collected every sixth day parallel at two suburban sites (Libuš and Suchdol) located at the two opposite sides (south and north, respectively) of Prague, Czech Republic. The PM samples were analyzed for ions by ion chromatography (IC), organic and elemental carbon (OC and EC) by OC/EC analyzer and PM samples also for 56 elements by inductively coupled plasma-mass spectrometry (ICP-MS). The average annual PM and PM was 24.4 ± 13.0 μg m and 26.7 ± 15.1 μg m, respectively, in Prague-Libuš, and 25.1 ± 22.1 μg m and 27.1 ± 23.2 μg m, respectively, in Prague-Suchdol. Since the species forming large part of the aerosol mass were strongly correlated (Spearman's rank correlation coefficient r > 0.80), the variability of PM and PM concentration was mainly driven by the local meteorology or regional and/or long range transport. PM mass closure was calculated based on analytical results with the average percentage of recalculated mass of 77 ± 19% in Prague-Libuš and 86 ± 16% in Prague-Suchdol. The most abundant groups in PM at both sites during the four seasons were OM (Prague-Libuš 34% and Prague-Suchdol 37%) and SIA (Prague-Libuš 30% and Prague-Suchdol 34%). The Positive Matrix Factorization (PMF) was applied to the chemical composition of PM from both sites (124 samples) together to determine its sources. The nine factors were assigned as: mixed factor secondary sulphate and biomass burning, secondary sulphate, traffic, secondary nitrate, road dust, residential heating, aged sea salt, industry and mixed factor road salt along with aged sea salt. According to the polar plots and ventilation index (VI) east/west classification analysis the sources were separated based on origin to four categories local, urban agglomeration, regional and long range transport (LRT). The mixed source secondary sulphate and biomass burning, residential heating and industry were common sources of local origin at both sites. Prague-Suchdol was influenced by traffic related pollution from the urban agglomeration more than Prague-Libuš where the traffic and road dust/salt were of local origin. The regional pollution by secondary sulphates and nitrate was also relevant at both sites along with long range transport of sea salt from North Atlantic Ocean, Norwegian Sea and North Sea. The contribution of the local sources to PM was significant mainly at Prague-Libuš site. However, the sources of regional origin were also important and influence of urban agglomeration pollution to PM is not negligible as well.
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http://dx.doi.org/10.1016/j.scitotenv.2019.01.426DOI Listing
May 2019

Areas under high ozone and nitrogen loads are spatially disjunct in Czech forests.

Sci Total Environ 2019 Mar 26;656:567-575. Epub 2018 Nov 26.

Czech Hydrometeorological Institute, Prague, Czech Republic.

It is widely accepted that excessive loads of nitrogen (N) deposition and ambient ozone (O) endanger natural ecosystems and the environment. Despite substantial reductions in emissions since the early 1990s both in the Czech Republic and in neighbouring countries, neither O exposures nor N deposition have yet decreased to acceptable levels relative to the recommended thresholds. Based on long-term monitoring and high-quality data, we have indicated the areas of special risk due to high N deposition and O exposures in Czech forests in 2000-2015. The areas of potential risk denote those forests under the highest loads of N deposition and O exposure on a regular basis. The underlying classification approach is relativistic, i.e. based ultimately on quartiles of pollution intensities and not derived from critical limits or loads. The forest areas under the highest O exposures and N deposition are spatially disjunct. The highest O exposures are in the southern and the highest N deposition is in the northern Czech Republic. In contrast to our assumption, only 1322 km, i.e. 4.6% of the total forested area (28,782 km) are overlapping areas with a potential risk due both to high O exposures and to N deposition. Our results provide valuable input information for a more detailed environmental analysis, anticipated in the future, addressing to what extent the indicated areas at potential risk are associated with the actual negative impacts on forests.
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http://dx.doi.org/10.1016/j.scitotenv.2018.11.371DOI Listing
March 2019

Revisiting fog as an important constituent of the atmosphere.

Sci Total Environ 2018 Sep 6;636:1490-1499. Epub 2018 May 6.

Czech Hydrometeorological Institute, Prague, Czech Republic.

We examined observation-based fog occurrence at three Czech monitoring sites: Praha 4 - Libuš, Košetice and Churáňov, representing different environments - urban, rural and mountain - over a time span of 27 years (1989-2015). We searched for a simple model describing fog occurrence fitting the observed air pollution and meteorological data. For our analysis we used a generalized additive model, GAM, with (penalized) spline components to capture possible nonlinear and a priori unknown functional relationships. In order to cope with the binary nature of the data (indicators of fog presence on individual days), we employed a logistic regression GAM model fitted by a maximizing penalized likelihood (where the penalty coefficients were estimated via cross-validation). After testing several physically motivated models, being guided by AIC and physical interpretation of the components, we arrived at a model which uses the following explanatory variables: relative humidity, ambient SO concentrations, ambient NO concentrations, air temperature and seasonality. All associations between the response and the analysed explanatory variables were highly significant. According to our results, the most important explanatory variables modelling the fog probability were relative humidity and air pollutants. Interestingly, we observed an increasing trend in fog occurrence at all three sites under review starting around the mid 2000s.

Capsule: The most important explanatory variables modelling the fog probability at three Central European sites were humidity, SO and NO. An increasing trend in fog occurrence has been observed since the mid 2000s.
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http://dx.doi.org/10.1016/j.scitotenv.2018.04.322DOI Listing
September 2018

Environmental factors exert strong control over the climate-growth relationships of Picea abies in Central Europe.

Sci Total Environ 2017 Dec 26;609:506-516. Epub 2017 Jul 26.

IFER - Institute of Forest Ecosystem Research, Jílové u Prahy, Czech Republic.

The growth response of trees to changing climate is frequently discussed as increasing temperatures and more severe droughts become major risks for forest ecosystems. However, the ability of trees to cope with the changing climate and the effects of other environmental factors on climate-growth relationships are still poorly understood. There is thus an increasing need to understand the ability of individual trees to cope with changing climate in various environments. To improve the current understanding, a large tree-ring network covering the whole area of the Czech Republic (in 7×7km grids) was utilized to investigate how the climate-growth relationships of Norway spruce are affected by 1) various geographical variables, 2) changing levels of acidic deposition, 3) soil characteristics and 4) age, tree diameter and neighbourhood competition. The period from 1930 to 2013 was divided into four, 21-year long intervals of differing levels of acidic deposition, which peaked in the 1972-1993 period. Our individual-based, spatiotemporal, multivariate analyses revealed that spruce growth was mostly affected by drought and warm summers. Drought plays the most important negative role at lower altitudes, while the positive effect of higher temperature was identified for trees at higher altitudes. Increased levels of acidic deposition, together with geographical variables, were identified as the most important factors affecting climate-growth association. Tree age, tree size and soil characteristics also significantly modulate climate-growth relationships. The importance of all environmental variables on climate-growth relationships was suppressed by acidic deposition during periods when this was at a high level; growth was significantly more enhanced by spring and summer temperatures during these periods. Our results suggest that spruce will undergo significant growth reduction under the predicted climate changes, especially at the lower altitudes which lie outside of its natural range.
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http://dx.doi.org/10.1016/j.scitotenv.2017.07.134DOI Listing
December 2017

Discerning environmental factors affecting current tree growth in Central Europe.

Sci Total Environ 2016 Dec 27;573:541-554. Epub 2016 Aug 27.

Swedish University of Agricultural Sciences, Faculty of Forest Sciences, Department of Forest Resource Management, SE-901 83 Umeå, Sweden.

We examined the effect of individual environmental factors on the current spruce tree growth assessed from a repeated country-level statistical landscape (incl. forest) survey in the Czech Republic. An extensive set of variables related to tree size, competition, site characteristics including soil texture, chemistry, N deposition and climate was tested within a random-effect model to explain growth in the conditions of dominantly managed forest ecosystems. The current spruce basal area increment was assessed from two consecutive landscape surveys conducted in 2008/2009 and six years later in 2014/2015. Tree size, age and competition within forest stands were found to be the dominant explanatory variables, whereas the expression of site characteristics, environmental and climatic drives was weaker. The significant site variables affecting growth included soil C/N ratio and soil exchangeable acidity (pH KCl; positive response) reflecting soil chemistry, long-term N-deposition (averaged since 1975) in combination with soil texture (clay content) and Standardized Precipitation Index (SPI), a drought index expressing moisture conditions. Sensitivity of growth to N-deposition was positive, although weak. SPI was positively related to and significant in explaining tree growth when expressed for the growth season. Except SPI, no significant relation of growth was determined to altitude-related variables (temperature, growth season length). We identified the current spruce growth optimum at elevations about 800ma.s.l. or higher in the conditions of the country. This suggests that at lower elevations, limitation by a more pronounced water deficit dominates, whereas direct temperature limitation may concern the less frequent higher elevations. The mixed linear model of spruce tree growth explained 55 and 65% of the variability with fixed and random effects included, respectively, and provided new insights on the current spruce tree growth and factors affecting it within the environmental gradients of the country.
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http://dx.doi.org/10.1016/j.scitotenv.2016.08.115DOI Listing
December 2016

Towards a better spatial quantification of nitrogen deposition: A case study for Czech forests.

Environ Pollut 2016 Jun 15;213:1028-1041. Epub 2016 Feb 15.

Czech Hydrometeorological Institute, Prague, Czech Republic.

The quantification of atmospheric deposition flux is essential for assessment of its impact on ecosystems. We present an advanced approach for the estimation of the spatial pattern of atmospheric nitrogen deposition flux over the Czech forests, collating all available measured data and model results. The aim of the presented study is to provide an improved, more complete, more reliable and more realistic estimate of the spatial pattern of nitrogen deposition flux over one country. This has so far usually been based on measurements of ambient NOx concentrations as dry deposition proxy, and [Formula: see text] and [Formula: see text] in precipitation as wet deposition proxy. For estimation of unmeasured species contributing to dry deposition, we used the CAMx Eulerian photochemical dispersion model, coupled with the Aladin regional numeric weather prediction model. The contribution of fog and dissolved organic nitrogen was estimated using a geostatistical data driven model. We prepared individual maps for particular components applying the most relevant approach and then merged all layers to obtain a final map representing the best estimate of nitrogen deposition over the Czech Republic. Final maps accounting for unmeasured species clearly indicate that the approach used so far may result in a substantial underestimation of nitrogen deposition flux. Our results showed that nitrogen deposition over the Czech forested area in 2008 was well above 2 g N m(-2) yr(-1), with almost 70% of forested area receiving 3-4 g N m(-2) yr(-1). NH3 and gaseous HNO3, contributing about 80%, dominated the dry nitrogen deposition. Estimating the unmeasured nitrogen species by modeled values provides realistic approximations of total nitrogen deposition that also result in more realistic spatial patterns that could be used as input for further studies of likely nitrogen impacts on ecosystems.
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http://dx.doi.org/10.1016/j.envpol.2016.01.061DOI Listing
June 2016

Spatial and temporal trends of ozone distribution in the Jizerské hory Mountains of the Czech Republic.

Environ Sci Pollut Res Int 2016 Jan 27;23(1):377-87. Epub 2015 Aug 27.

T.G.Masaryk Water Research Institute, Prague, Czech Republic.

We present results of the 5-year monitoring of ambient O3 concentrations in a Central European medium altitude mountain forested area. O3 levels were measured at 11 sites between 714 and 1000 m a.s.l. in 2006-2010 vegetation seasons using Ogawa diffusive samplers. Our results reveal that O3 exposure in the Jizerské hory Mts. was relatively high and comparable with polluted sites in Southern Europe and in higher altitudes. O3 concentrations differed significantly between individual sites and in individual years. O3 concentrations showed clear dependence on altitude at sites with similar aspect. Its gradient for the entire 5-year period under review equaled 3.5 ppb/100 m of altitude, ranging between nearly 5 ppb/100 m of altitude in 2006 and nearly 3 ppb/100 m of altitude in 2010. O3 concentrations at the site with northern aspect were consistently significantly lower than at the site at similar altitude with southern aspect. O3 concentrations measured at the forest edge were consistently lower than those measured at the same site but at the forest clearing. It is evident that the macro-setting of the O3 monitoring site is crucial for obtaining reliable results with high representativeness for the area.
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http://dx.doi.org/10.1007/s11356-015-5258-0DOI Listing
January 2016

Stomatal ozone flux and visible leaf injury in native juvenile trees of Fagus sylvatica L.: a field study from the Jizerske hory Mts., the Czech Republic.

Environ Sci Pollut Res Int 2015 Jul 13;22(13):10034-46. Epub 2015 Feb 13.

Institute for Environmental Studies, Faculty of Science, Charles University in Prague, Benatska 2, 128 01, Prague 2, Czech Republic,

The study was carried out at six sites in the Jizerskehory Mts. in the north of the Czech Republic. At all these sites, ranging in altitude between 460 and 962 m a. s. l., and during the period from June to September in 2008, O3 concentrations and environmental parameters important for accumulated stomatal O3 flux (AFst) into Fagus sylvatica leaves were measured. At five sites, visible injury on Fagus sylvatica L. juvenile tree leaves was observed. A combination of actual O3 levels in the Jizerkehory Mts. and environmental conditions, though relative air humidity and air temperature significantly limited stomatal conductance, has been sufficient enough to cause O3 uptake exceeding the critical level (CL) for forest ecosystems. The AFst values ranged between 13.4 and 22.3 mmol O3 m(-2). The CL for the accumulated stomatal flux of O3 above a flux threshold 1.6 nmol m(-2) s(-1) (AFst1.6) was exceeded at all sites from ca 45 to 270% (160% on average). The CL of 5 ppm h(-1) for AOT40 (accumulated O3 exposure above threshold of 40 ppb) was exceeded at four sites. The relationship between visible injury on O3 indices was found. The conclusions based on AOT40 and AFSt are not the same. AFSt has been determined as better predictor of visible injury than AOT40.
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http://dx.doi.org/10.1007/s11356-015-4174-7DOI Listing
July 2015

Trends in atmospheric deposition fluxes of sulphur and nitrogen in Czech forests.

Environ Pollut 2014 Jan 14;184:668-75. Epub 2013 Jun 14.

Czech Hydrometeorological Institute, Na Šabatce 17, 143 06 Prague 4 - Komořany, Czech Republic. Electronic address:

We present the temporal trends and spatial changes of deposition of sulphur and nitrogen in Czech forests based on records from long-term monitoring. A statistically significant trend for sulphur was detected at most of the sites measuring for wet, dry, and total deposition fluxes and at many of these the trend was also present for the period after 2000. The spatial pattern of the changes in sulphur deposition flux between 1995 and 2011 shows the decrease over the entire forested area in a wide range of 18.1-0.2 g m(-2) year(-1) with the most pronounced improvement in formerly most impacted regions. Nitrogen still represents a considerable stress in many areas. The value of nitrogen deposition flux of 1 g m(-2) year(-1) is exceeded over a significant portion of the country. On an equivalent basis, the ion ratios of NO3(-)/SO4(2-) and NH4(+)/SO4(2-) in precipitation show significantly increasing trends in time similarly to those of pH.
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http://dx.doi.org/10.1016/j.envpol.2013.05.013DOI Listing
January 2014

The influence of climate change on stomatal ozone flux to a mountain Norway spruce forest.

Environ Pollut 2012 Oct 6;169:267-73. Epub 2012 Jun 6.

Silesian University at Opava, Faculty of Philosophy and Science, Opava, Czech Republic.

Daily stomatal ozone flux to a mountain Norway spruce forest stand at the Bily Kriz experimental site in the Beskydy Mts. (Czech Republic) was modelled using a multiplicative model during the 2009 growing season. The multiplicative model was run with meteorological data for the growing season 2009 and ALADIN-CLIMATE/CZ model data for the 2030 growing season. The exceedance of the flux-based critical level of O(3) (Phytotoxic Ozone Dose) might be lower for Norway spruce at the Bily Kriz experimental site in a future climate (around 2030), due to increased stomatal closure induced by climate change, even when taking into account increased tropospheric background O(3) concentration. In contrast, exceedance of the concentration-based critical level (AOT40) of O(3) will increase with the projected increase in background O(3) concentration. Ozone concentration and stomatal flux of ozone significantly decreased NEP under both present and future climatic conditions, especially under high intensities of solar radiation.
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http://dx.doi.org/10.1016/j.envpol.2012.05.008DOI Listing
October 2012

Monitoring of ozone effects on the vitality and increment of Norway spruce and European beech in the Central European forests.

J Environ Monit 2012 May 25;14(6):1696-702. Epub 2012 Apr 25.

Forestry and Game Management Research Institute, Strnady 136, 252 02 Jíloviště, Czech Republic.

The ozone effect on Norway spruce (Picea abies (L) Karst.) and European beech (Fagus sylvatica L.) was studied on 48 monitoring plots in 2005-2008. These plots represent two major forest tree species stands of different ages in eight regions of the Czech Republic. The forest conditions were represented by defoliation and the annual radial increment of individual trees. The ozone exposure was assessed by using modeled values of mean annual O(3) concentration and the AOT40 index. The malondialdehyde (MDA) content of the foliage was analysed and used as an indicator of oxidative stress. The correlation analysis showed a significant relation of Norway spruce defoliation to the AOT40 exposure index, and European beech defoliation to the MDA level. The radial increment response to ozone was significant only for the European beech: (a) the correlation analysis showed its decrease with increasing AOT40; (b) the regression model showed its decrease with increasing mean annual ozone concentration only at lower altitudes (<700 m a.s.l.).
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http://dx.doi.org/10.1039/c2em10964fDOI Listing
May 2012

Association between ambient ozone and health outcomes in Prague.

Int Arch Occup Environ Health 2013 Jan 25;86(1):89-97. Epub 2012 Feb 25.

Faculty of Science, Institute for Environmental Studies, Charles University in Prague, Prague, Czech Republic,

Purpose: Though numerous studies investigating ambient ozone (O(3)) effects on human health were published, such a study for Central Europe is still lacking. We have investigated the association between ozone (O(3)) levels and hospital admissions and mortality due to cardiovascular and respiratory diseases for Prague inhabitants for summer months (April-September) over the 5-year period 2002-2006. Our hypothesis was that ambient O(3) levels in Prague resulted in adverse health outcomes and were associated with increased mortality and hospital admissions.

Methods: The effect of O(3) on mortality and hospital admissions was investigated using the negative binomial regression after controlling for the influence of meteorological factors (air temperature and relative humidity) and calendar effects (seasonal patterns, long-term trends and day of week).

Results: We found a statistically significant association between O(3) levels and daily mortality from respiratory diseases. Relative risk of 1.080 (95% CI: 1.031-1.132) was observed for mortality from respiratory diseases per 10 μg m(-3) increase in 1-day lagged daily mean O(3) concentration. No statistically significant association was detected between O(3) concentrations and daily mortality from all causes, daily mortality from cardiovascular diseases and hospital admissions for respiratory and cardiovascular diseases. The O(3) effects differed in men and women, nevertheless, the results were ambiguous with respect to used lag and O(3) metrics. No significant confounding effects of PM(10) on the investigated association were observed.

Conclusions: O(3) exposure in Prague, though lower as compared to many other cities in Europe, is high enough to cause adverse health effects.
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http://dx.doi.org/10.1007/s00420-012-0751-yDOI Listing
January 2013

Ozone influence on native vegetation in the Jizerske hory Mts. of the Czech Republic: results based on ozone exposure and ozone-induced visible symptoms.

Environ Monit Assess 2011 Dec 4;183(1-4):501-15. Epub 2011 Mar 4.

Czech Hydrometeorological Institute, Na Sabatce 17, 143 06 Prague 4 Komorany, Czech Republic.

Ozone levels in the Jizerske hory Mts. measured at 13 sites by diffusive samplers during the 2006 and 2007 vegetation seasons are presented. A significant ozone gradient (5.4 ppb in 2006 and 4.0 ppb in 2007) per 100 m difference in altitude between 370 and 1,100 m a.s.l. was recorded. High-resolution maps of phytotoxic potential were developed. The AOT40 threshold (5 ppm h) was exceeded over the entire area with the highest levels exceeding this threshold by 12 times in the upper portions of the mountains. Ozone visible injury was evaluated at four of the monitoring sites on seven native plant and tree species. Four species showed ozone-like symptoms, two of which (Rubus idaeus and Fagus sylvatica) were confirmed as ozone-induced. Our results indicate that ambient ozone is likely to have a much lower impact on the Jizerske hory Mts. vegetation than expected, considering the measured ambient ozone exposures and favourable environmental conditions for ozone uptake.
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http://dx.doi.org/10.1007/s10661-011-1935-8DOI Listing
December 2011

The impact of ambient ozone on mountain spruce forests in the Czech Republic as indicated by malondialdehyde.

Environ Pollut 2010 Jul 13;158(7):2393-401. Epub 2010 May 13.

Czech Hydrometeorological Institute, Na Sabatce 17, 143 06 Prague 4-Komorany, Czech Republic.

Malondialdehyde (MDA), a product of lipid peroxidation and biomarker of oxidative stress, is measured over the long term in spruce Picea abies needles under real conditions in three Czech mountain border areas. The trends presented collate the MDA content in spruce needles with ambient ozone, temperature and precipitation as casual, and defoliation as a subsequent factor for the period 1994-2006. We have found the overall decreasing trends in MDA and defoliation. The highest MDA and defoliation are recorded in the Jizerske, the lowest in the Krusne hory Mts. Out of the examined variables the MDA is predicted best by mean temperature in vegetation season, median of O(3) concentrations and AOT40; these three variables account for 34% of MDA1 and 36% of MDA2 variability. Our hypothesis that higher ambient O(3) exposure results in higher MDA contents in P. abies needles under real conditions has not been approved.
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http://dx.doi.org/10.1016/j.envpol.2010.04.006DOI Listing
July 2010

Ambient air quality for the territory of the Czech Republic in 1996-1999 expressed by three essential factors.

Authors:
Iva Hůnová

Sci Total Environ 2003 Mar;303(3):245-51

Czech Hydrometeorological Institute, Na Sabatce 17, 143 06 4-Komorany, Prague, Czech Republic.

A new method for spatial interpretation and visualisation of measured air quality data developed and introduced in 1998 is used for ambient air quality assessment in the Czech Republic. The data from a countrywide air quality monitoring network is collated into the least possible number of factors describing the overall air quality in 1996-1999. The factors identified as 'ambient air pollution', 'ground-level ozone' and 'wet atmospheric deposition' represent three different aspects of ambient air quality and their impact on receptors' evaluation. The monitoring stations are classified for each factor using five categories clearly distinguishing the sites over the Czech Republic territory within the 'best-worst' scale range. The results are presented in maps with spot symbols produced in Arc/View system. The problem areas within the country are identified clearly for each factor. The air quality picture differs considerably for the respective factors within one calendar year. Categorisation of each factor for the entire period under review, however, remains strikingly similar, indicating that in spite of partial improvement and some decreases in air pollutant concentration, the problem areas have remained more or less the same for each factor. Comparison of all three factors shows that the southern part of the country is in a certain simplification very clean as to the 'ambient air pollution' and 'wet atmospheric deposition' factors, while it is impacted as to the 'ground-level ozone' factor. In contrast, the northern part of the country impacted as to the 'ambient air pollution' along with the 'wet atmospheric deposition' and 'ground-level ozone' factors at the higher elevations.
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http://dx.doi.org/10.1016/S0048-9697(02)00493-XDOI Listing
March 2003