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AIR POLLUTION IN THE CZECH REPUBLIC IN 2008 Czech Hydrometeorological Institute - Air Quality Protection Division |
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II.4.2 Czech Republic II.4.2.1 Air quality with regard to health protection limit values II.4.2.1.1 Sulphur dioxide
Sulphur dioxide emitted from anthropogenic sources is created mainly by burning
the fossil fuels (mostly coal and heavy fuel oils) and by smelting ores
containing sulphur. Volcanos and oceans belong to the main global natural
sources of SO2, nevertheless their share on the territory within EMEP
(in which the Czech Republic is also participating) was estimated at only 2 %.
In the atmosphere, SO2 is oxidized to sulphates and H2SO4, creating
aerosol both in the form of droplets and suspended particles of broad size
range. SO2 and the substances originating from it are removed from
the atmosphere through wet and dry deposition. SO2 has irritating
effect, high concentrations can cause lung function impairment and the change of
lung capacity. In 2008 the set limit value for 24-hour SO2 concentration (125 μg.m-3, tolerated number of exceedances – 3) was not exceeded. The exceedance of the value 125 μg.m-3 (in the tolerated number) was recorded only in the locality Úštěk in the Ústí nad Labem Region. This station, probably influenced by a local source, recorded the increased SO2 concentrations already in the previous years. No locality reported the exceedance of the 1-hour SO2 limit value 350 μg.m-3 (the tolerated number of exceedances is 24). The highest number of exceedances of the value 350 μg.m-3 was recorded at the AMS station Ostrava-Zábřeh - 3.
The map diagrams in Fig. II.4.2.1 show the improvement of air quality resulting
from the significant decrease of SO2 concentrations documented by the
marked decline of the 4th highest 24-hour SO2
concentration at all stations in the period 1998–2000. In the following years
this decreasing trend stopped. The slight decrease in SO2
concentrations continued again from 2004 to 2005. After certain increase in 2006
the original decreasing trend of SO2 concentrations appeared again in
2007 in almost all localities of the Czech Republic. This decreasing trend was
confirmed in 2008, both as a result of more favourable meteorological and
dispersion conditions and the decrease of total SO2 emissions (REZZO
1). We suppose that certain increase of SO2 concentrations occurred
in the places where there is no measurement, and it was probably caused by the
return to coal combustion in local furnaces in some settlements. Fig. II.4.2.2 presents the spatial distribution of the 4th highest 24-hour SO2 concentration. On only 0.44 % of the territory of the Czech Republic the SO2 concentrations exceeded the lower assessment threshold (LAT). This confirms the marked decrease of air pollution caused by SO2 as compared with the previous year. Tab. II.4.2.1 Stations with the highest values of the 25th and maximum hourly concentrations of SO2 Tab. II.4.2.2 Stations with the highest numbers of exceedances of the 24-hour limit value of SO2 Tab. II.4.2.3 Stations with the highest values of annual average concentrations of SO2 Fig. II.4.2.1 4th highest 24-hour concentrations and 25th highest hourly concentrations of SO2 in 1998-2008 at selected stations
Fig. II.4.2.2 Field of the 4th highest 24-hour concentration of SO2 in 2008
Fig. II.4.2.3 Stations with the highest hourly concentrations of SO2 in 2008
Fig. II.4.2.4 Stations with the highest 24-hour concentrations of SO2 in 2008
II. 4.2.1.2 Suspended particles, PM10 fraction and PM2.5 fraction The particles contained in the ambient air can be divided into primary and secondary particles. The primary particles are emitted directly into the atmosphere, both from natural and anthropogenic sources. Secondary particles are mostly of anthropogenic origin and are created by oxidation and consequent reactions of gaseous compounds in the atmosphere. Similarly as in the whole Europe, most emissions in the Czech Republic are of anthropogenic origin. The main anthropogenic sources include: transport, power stations, combustion sources (industrial and local), fugitive emissions from industry, loading/unloading, mining and building activities. Due to the diversity of emission sources the suspended particles have various chemical composition and various size. The PM10 suspended particles have serious health impacts appearing already at low concentrations without a clear lower safe concentrations threshold. Health impacts of particles are influenced by their concentration, size, shape and chemical composition. They can cause hypo-immunity, inflammation of lung tissue and oxidative stress. Increased concentrations are responsible for cardiovascular diseases and acute trombotic complications. Persistent exposure can result in respiration diseases, damaged lung function and increased mortality (lower life expectancy). Recently it has been proved that the most serious health impacts (incl. increased mortality) are recorded in PM 2.5 or PM1 fractions which enter the lower parts of the respiratory system when inhaled. Air pollution caused by PM10 remains one of the main problems of air quality assurance. This situation is confirmed by Tables II.4.2.4 and II.4.2.5, similarly as by Fig. II.4.2.5, showing the obviously increasing trend of PM10 pollution at almost all stations in the Czech Republic from 2001 to 2003. In 2004 this trend stopped but in 2005 the PM10 concentrations increased again at almost all selected stations. In 2006 this trend continued at most stations in annual averages. In 2007, on the contrary, the decrease of PM10 concentrations was recorded. In 2008 the decreasing trend continued at most stations, mainly in daily concentrations. The most affected area of large coverage is, similarly as in the previous years, the Ostrava-Karviná area. The limit value of 24-hour PM10 concentration was exceeded in 2008, and namely at the stations in the Moravian-Silesian Region: Bohumín, Ostrava-Bartovice, Český Těšín, Věřnovice, Ostrava-Přívoz, Ostrava-Mariánské Hory, Orlová, Karviná, Karviná-ZÚ, Ostrava-Českobratrská (hot spot), Havířov, Ostrava-Fifejdy and Ostrava-Zábřeh; at the stations of the South-Moravian Region: Brno-Úvoz (hot spot), Brno-Svatoplukova and Brno-Zvonařka; of the Vysočina Region: Jihlava-Znojemská; at the stations in the capital city of Prague: Prague 2-Legerova (hot spot) and Prague 5-Smíchov; of the Olomouc Region: Olomouc-Velkomoravská and Šumperk MÚ; of the Central Bohemian Region: Stehelčeves, Kladno-Švermov and Beroun;, of the Ústí nad Labem Region: Lom, Děčín, Ústí n.L.-město and Ústí n.L.-Všebořická (hot spot); of the South Bohemian Region: Tábor; and in the Zlín Region: Zlín-Svit and Uherské Hradiště. Of the total number of 153 localities in which PM10 measurements were carried out, 47 stations reported exceedances of 24-hour PM10 limit value (in 2007 at 54). The annual PM10 limit value was exceeded at 15 stations (in 2007 at 16). The number of localities which exceeded the limit value in both above air pollution characteristics of PM10 fraction slightly decreased in 2008 as compared with 2007. This decrease was influenced by more favourable meteorological and dispersion conditions, mainly by warmer months of November and December, moister April and lower number of days with anticyclonic character in 2008. The reduction of ambient air pollution caused by PM10 was influenced by the decrease of total emissions of solid substances (REZZO 1). As it is evident from Fig. II.4.2.6, in 2008 there was a reduction of the area with above-the-limit 24-hour concentrations of PM10, especially in the Olomouc Region and the Moravian-Silesian Region. Figs. II.4.2.6 and II.4.2.7 show, however, that PM10 limit value exceedances are still significant for listing the basic administrative units among the areas with deteriorated air quality. Especially Fig. II.4.2.6 shows quite evidently that in the towns where the PM10 measurements are carried out the 24-hour average concentrations are above the limit value. However, it can be admitted that also in the towns without PM10 measurements the concentrations of this pollutant can be high or exceeding the limit value. The spatial projections of PM10 concentrations show, that in 2008 the respective limit values for PM10 were exceeded in 2.9 % of the territory of the Czech Republic with approx. 15 % of inhabitants. The graphs of courses of 24-hour concentrations of PM10 in 2008 at the stations, where the limit values for annual average and for 24-hour average were exceeded, are shown in Figs. II.4.2.8 and II.4.2.9. The PM10 24-hour limit value was exceeded in 20 localities in the Moravian-Silesian Region. Fig. II.4.2.10 presents the numbers of exceedances of the PM10 24-hour limit value. The complete overview of the exceedances of the limit value for the PM10 annual average concentration for the recent 5 years is presented in Fig. II.4.2.11 and Table II.4.2.6, showing the annual average PM10 concentrations for the period 2004–2008 at the localities where at least once in this period the annual limit value was exceeded. Table II.4.2.6 shows the particular values of the reached average PM10 concentrations. Annual average concentrations exceeding the limit value are printed bold. Since 2004 the fine fraction of suspended particles (PM2.5) has been measured in the Czech Republic. In 2008 the measurements were carried out in 35 localities which fulfilled the requirement for the minimum number of measured data for the assessment. The measurement results show significant contribution of PM2.5 fraction to air pollution situation in the part of the territory of the Moravian-Silesian Region. When comparing the results with the annual target value pursuant to the Directive 2008/50/EC of the European Parliament and of the Council (25 μg.m-3), it is evident that in 9 localities the target value was exceeded (5 in 2007). These are the stations in the Ostrava-Karviná area (Bohumín, Věřňovice, Ostrava-Přívoz, Ostrava-Zábřeh, Třinec-Kosmos and Ostrava-Poruba/CHMI) and in Brno (Brno-Svatoplukova, Brno-Zvonařka and Brno Výstaviště). The stations with the highest values of annual average concentrations of PM2.5 are presented in Table II.4.2.7. The annual average PM2.5 concentrations in the localities which measured this fraction in 2008 are presented in Fig. II.4.2.13 in the form of spot symbols. The annual average PM2.5 concentrations at individual stations in the period 2004–2008 are presented in Fig. II.4.2.12. Fig. II.4.2.15 shows the courses of daily PM2.5 concentrations with
regard to the exceedance of the annual target value of this pollutant pursuant
to the Directive 2008/50/EC. The exceedance of this PM2.5 limit value
was recorded only in the localities of the Moravian-Silesian Region and in the
territory of the city of Brno. The seasonal course of PM2.5/PM10 fraction ratio is connected with the seasonal character of several emission sources. Emissions from combustion sources show higher shares of PM2.5 fraction than for instance emissions from agriculture and reemissions during dry and windy weather. Consequently, heating in the winter period can cause the higher share of PM2.5 fraction in comparison with PM10 fraction. The decrease during the spring and early summer is also explained by the increased amount of larger biogenic particles (e.g. pollen) by some authors [29]. The lowest PM2.5/PM10 ratio is at traffic stations. During fuel combustion the emitted particles occur mainly in PM2.5 fraction and thus the ratio should be high in traffic localities. The fact that this is not the case, accents the significance of emissions of larger particles caused by tire, break lining and road surface abrasion. Higher PM2.5/PM10 ratio in the stations of the Moravian-Silesian Region is connected with a great share of industrial sources in the Ostrava-Karviná area, where the stations measuring PM2.5 are located. Tab. II.4.2.4 Stations with the highest numbers of exceedances of the 24-hour limit value of PM10 Tab. II.4.2.5 Stations with the highest values of annual average concentrations of PM10 Tab. II.4.2.7 Stations with the highest values of annual average concentrations of PM2.5 Fig. II.4.2.5 36th highest 24-hour concentrations and annual average concentrations of PM10 in 1998–2008 at selected stations
Fig. II.4.2.6 Field of the 36th highest 24-hour concentration of PM10 in 2008
Fig. II.4.2.7 Field of annual average concentration of PM10 in 2008
Fig. II.4.2.8 Stations with the highest exceedance of LV for 24-hour concentrations of PM10 in 2008
Fig. II.4.2.9 Stations with the highest exceedance of LV for annual concentrations of PM10 in 2008
Fig. II.4.2.10 Numbers of exceedances of air pollution limit value for the highest 24-hour concentration of PM10 in 2008
Fig. II.4.2.11 Annual average PM10 concentrations at the stations with the exceedance of the limit value, 2004–2008
Fig. II.4.2.12 Annual average concentrations of PM2.5 in the ambient air in 2004-2008 at selected stations
Fig. II.4.2.13 Annual average concentration of PM2.5 at stations in 2008
Fig. II.4.2.14 Average monthly PM2.5/PM10 ratio in 2008
Fig. II.4.2.15 Stations with the highest exceedance of LV for annual concentrations of PM2.5 in 2008
II.4.2.1.3 Nitrogen dioxide In the field of ambient air monitoring and assessment the term nitrogen oxides NOx is used for the mixture of NO and NO2. Air pollution limit value for the protection of human health is set for NO2, the limit value for the protection of ecosystems and vegetation is set for NOx. More than 90 % of the total nitrogen oxides in the ambient air are emitted in the form of NO. NO2 is formed relatively quickly in the reaction of NO with ground-level ozone or with HO2 or RO2 radicals. In a number of chemical reactions part of NOx is transformed to HNO3/NO3-, which are removed from the atmosphere through deposition (both dry and wet). NO2 is dealt with due to its negative influence on human health. It plays also the key role in the formation of photochemical oxidants. In Europe, NOx emissions result mainly from anthropogenic combustion processes during which NO is formed in reaction between nitrogen and oxygen in the combusted air, and partly also by oxidation of nitrogen from the fuel. Road transport is the main anthropogenic source (significant shares however, have also air transport and water transport), and also combustion processes in stationary sources. Less than 10 % of total NOx emissions result from combustion directly in the form of NO2. Natural NOx emissions result mainly from soil, volcanic activity and creation of bolts of lightning. Globally, they are important, on the European scale, however, they represent less than 10 % of total emissions. Exposure to the increased NO2 concentrations affects lung function and can cause lower immunity. The exceedances of annual limit values for NO2 occur only in limited number of stations, and namely in the localities in agglomerations and large cities exposed to traffic. Of the total number of 175 localities in which NO2 was monitored in 2008 the annual limit value was exceeded at 13 stations (Table II.4.2.9). This limit value plus the margin of tolerance (44 μg.m-3) was exceeded at 8 localities, and namely at 5 stations in Prague (Prague 5-Svornosti, Prague 8-Sokolovská, Prague 2-Legerova (hot spot station), Prague 1-Národní muzeum and Prague 5-Smíchov), at 2 localities in Brno (Brno-Úvoz (hot spot station) and Brno-Svatoplukova) and at one in Ostrava (Ostrava-Českobratrská (hot spot station). All the measuring sites are significantly influenced by traffic. It can be expected that the exceedances of the limit values can occur also at other localities exposed to traffic, where there is no measurement. The AMS traffic-oriented (hot spot) Prague 2-Legerova station recorded, similarly as in the previous years, a great number of exceedances (106) of the limit value for NO2 hourly concentration 200 μg.m-3. In 2008 this AMS exceeded also the hourly limit value plus the margin of tolerance 220 μg.m-3 (38x). The measurement results of this station confirm again the constant big problem of the capital city of Prague with the traffic routes leading through the city centre. At most stations presented in Fig. II.4.2.16 both the annual average concentration and the 19th highest hourly NO2 concentration had a moderately declining trend until 2001. In 2002 this trend stopped and in 2003 there was a slight increase of NO2 pollution at most localities. In 2004 a slight decrease was recorded but in 2005 the increasing trend of NO2 concentrations continued again, and it was confirmed in 2006 at almost all stations. In 2007 a marked decrease of NO2 concentrations was recorded at the stations due to more favourable meteorological and dispersion conditions. In 2008 this trend continued but it was not as steep as in the previous year. In addition to meteorological conditions this was contributed by the reduction of total NOx emissions.
The field of NO2 annual average concentration (Fig.
II.4.2.17) gives
evidence of air pollution in the cities caused mainly by traffic. When constructing the map in Fig. II.4.2.17 also national traffic census from the year 2005 was regarded. As compared with the previous census in 2000, i.e. during the recent 5 years, the increase of traffic is significant. The higher NO2 concentrations can occur also in the vicinity of local communications with intensive traffic and dense local transport network. Tab. II.4.2.8 Stations with the highest values of the 19th and maximum hourly concentrations of NO2 Tab. II.4.2.9 Stations with the highest values of annual average concentrations of NO2 Fig. II.4.2.16 19th highest hourly concentrations and annual average concentrations of NO2 in 1998–2008 at selected stations
Fig. II.4.2.17 Field of annual average concentration of NO2 in 2008
Fig. II.4.2.18 Stations with the highest hourly concentrations of NO2 in 2008
Fig. II.4.2.19 Stations with the highest exceedance of LV and LV+MT for annual concentrations of NO2 in 2008
The insufficient burning of fossil fuels may be an anthropogenic source of air
pollution caused by carbon monoxide. These processes occur mainly in transport
and in stationary sources, namely household heating. In 2008 carbon monoxide concentrations were measured at 43 localities. Maximum daily 8-hour running averages of carbon monoxide did not exceed the limit value (10 mg.m-3) at any of the stations. The highest daily 8-hour average concentration was measured, similarly as in 2007, at the hot spot locality Ostrava-Českobratrská (5,023.3 μg.m-3). Similarly as in 2006 the lower assessment threshold was slightly exceeded in this locality. The courses of maximum daily 8-hour running averages for selected localities are presented in Fig. II.4.2.21. The air pollution situation caused by carbon monoxide in 2008 is characterized in Table II.4.2.10. Fig. II.4.2.20 Maximum 8-hour running average concentrations of CO in 1998–2008 at selected stations
Fig. II.4.2.21 Stations with the highest values of maximum 8-hour running average concentrations of CO in 2008
II.4.2.1.5 Benzene The anthropogenic sources produce more than 90 % of total emissions in the air. The decisive emission sources are combustion processes, mainly mobile sources, representing about 85 % of total anthropogenic emissions of aromatic hydrocarbons. The prevailing share is contributed by exhaust gases emissions. It is estimated that the remaining 15 % of emissions come from stationary sources. Many of these are related to industries producing aromatic hydrocarbons and the industries that use these compounds to produce other chemicals. Another significant source is represented by loss evaporative emissions produced during petrol handling, storing and distribution. Exhaust benzene is produced primarily by unburned benzene from fuels. Non-benzene aromatics or non-aromatic hydrocarbons in the fuels can contribute to exhaust benzene emissions. The most significant adverse effects from exposure to benzene are haematotoxicity and carcinogenicity [16]. In 2008 benzene concentrations were measured in total in 29 localities with
valid annual average. The limit value is defined as an annual average
concentration 5 μg.m-3. This limit must be achieved by 31.12.2009.
The margin of tolerance for the year 2008 reached the value of 2 μg.m-3.
The highest annual average concentration (6.7 μg.m-3) was measured in
the CHMI locality Ostrava-Přívoz, similarly as in 2007 (8 μg.m-3).
Consequently, the limit value in this locality was exceeded in 2008,
nevertheless the limit value + the margin of tolerance was not exceeded. Higher
concentrations in this area are connected with industrial activities (mainly
with coke production). The number of localities with a slight decrease of
average annual concentration as compared with 2007, was comparable with the
number of localities with a slight increase. Tab. II.4.2.11 Stations with the highest values of annual average concentrations of benzene Fig. II.4.2.22 Annual average concentrations of benzene in 1998–2008 at selected stations
Fig. II.4.2.23 Field of annual average concentration of benzene in the ambient air in 2008
Fig. II.4.2.24 24-hour concentrations at the stations with the highest annual benzene concentrations in 2008
II.4.2.1.6 Ground-level ozone Ground-level ozone is a secondary pollutant in the ambient air with no significant emission source of its own. It is formed under the influence of solar radiation during complex photochemical reactions mainly between nitrogen oxides, VOCs (mainly hydrocarbons) and other components of the atmosphere. Ozone is a very powerful oxidizing agent. Ozone impairs mainly the respiratory system and irritates mucous membranes. It causes morphological, biochemical and functional changes and impairs the immune system response. There is evidence for ozone toxicity to vegetation. The Government Order No. 597/2006 Coll. requires the assessment of ozone concentrations in relation to human health protection as an average for the latest three years. If the latest three years are not available, the average for the latest two years or one year is taken into account pursuant to the Government Order. In 2008 ozone was measured at 70 localities out of which 38 (54.3 %) exceeded the target value for the three-year period 2006–2008, or shorter (see Table II.4.2.12). According to this assessment the maximum number of exceedances was recorded, similarly as in the previous years, at the locality Churáňov, where the average number of exceedances of the maximum daily 8-hour running average 120 μg.m-3 reached the value of 62.7. The comparison of the assessed periods is based mainly on the meteorological conditions, i.e. the values of sun radiation, temperature and precipitation in the period from April to September when the highest ozone concentrations are measured usually. The comparison of the period 2006–2008 with the previous three-year period 2005–2007 shows that the relative number of stations with exceedances slightly decreased. The map with the 26th highest maximum daily 8-hour running averages shows clearly that in the monitored period 2006–2008, similarly as in the previous years, the target value was exceeded in the most territory of the Czech Republic (93.8 % of the area). In 2004–2006 the above-the-limit-concentrations were recorded in 88 % of the area, in the years 2005–2007 in 97 %. As compared with the period 2005–2007 most stations (almost 85 %) in the assessed period 2006–2008 recorded the lower number of exceedances of the value of 120 μg.m-3 (i.e. the target value) and also the similar decrease of the 26th highest maximum daily 8-hour running average of O3 concentration in average for three years. The decrease was probably caused by the reduction of ozone precursors concentrations. Air pollution concentrations of NOx decreased in 2008 as compared with the year 2005, which was already excluded from the three-year assessed period, approximately in two thirds of localities. Volatile organic compounds contributing to the creation of ground-level ozone, monitored at the stations Prague 4-Libuš and Košetice, decreased approx. in 70 % of cases. This decrease is not explained by the meteorological conditions in 2008. The temperature from April to September 2008, when there are usually measured the highest ozone concentrations, was similar as in the year 2005 (the average temperature 14.37 C and 14.31 C respectively). Further, in 2008 there was no significant decrease of maximum temperatures as compared with the year 2005and the average of the sums of total global radiation from April to September is comparable for both years.
The ground-level ozone concentrations generally grow with the increasing
altitude which is confirmed also by the data measured for the year 2008 when the
localities with highest loads (see Table II.4.2.12)
are situated at higher altitudes. The traffic localities in the cities are the
least loaded ones as ozone is degraded there through chemical reaction with NO.
It can be expected that the ozone concentrations are below the target value also
in other cities with heavier traffic. However, due to the absence of
measurements the probable decrease cannot be documented by the use of current
methods of map construction. Table II.4.2.12 presents the stations with the highest values of maximum daily 8-hour running average ozone concentrations in three-year average. Fig. II.4.2.27 shows the graph of the number of exceedances of the target value for ground-level ozone and Fig. II.4.2.28 presents the annual courses of maximum daily 8-hour running averages in the localities with the heaviest loads. Table II.4.2.13 presents the number of hours of the ozone alert threshold exceedance (180 μg.m-3) at selected AIM stations for the whole period of 1992–2008. Fig. II.4.2.25 26th highest values of maximum 8-hour running average of ground-level ozone concentrations (three-year average) in 1998–2008 at selected stations
Fig. II.4.2.26 Field of the 26th highest maximum daily 8-hour running average of ground-level ozone concentrations in three-year average, 2006–2008
Fig. II.4.2.27 Numbers of exceedances of the target value for the maximum daily 8-hour running average of ground-level ozone concentrations in three-year average, 2006–2008
Fig. II.4.2.28 Stations with the highest values of maximum daily 8-hour running average concentrations of ground-level ozone in 2005–2008
II.4.2.1.7 Heavy metals Lead The long-term exposure to lead results in harmful impacts on biosynthesis of haem (nonproteinic component of haemoglobin), on nervous system and blood pressure in humans. The evidence for carcinogenic potential of lead and its compounds in humans is inadequate [14, 15]. None of the 68 localities recorded the exceedance of the limit value (500 ng.m-3). The localities with the highest annual average, similarly as in the previous years, are located in Ostrava. In 2008 the highest concentration was reached, similarly as in 2007, in the ZÚ locality Ostrava-Bartovice (55.4 ng.m-3). As compared with the year 2007 the average annual concentration decreased almost by half. Lead concentrations in all localities remained far below the limit value and did
not even reach the lower assessment threshold (see Fig. II.4.2.29). Courses of
short-term average concentrations (24-hour or14-day concentrations, depending on
the measurement schedule of the given station) at selected stations are
presented in Fig. II.4.2.30. Fig. II.4.2.29 Annual average concentrations of lead in the ambient air in 1998–2008 at selected stations
Fig. II.4.2.30 1/14-day average concentrations of lead in the ambient air in 2008 at selected stations
Cadmium Cadmium is bound mainly to the fine particles (aerodynamic diameter up to 2.5 μm), with higher risk of negative effects on human health. Almost all cadmium is bound to particles up to 10 μm, while the minimum amount of cadmium is found in particles with diameter above 10 μm. The kidney is the critical organ with respect to long-term exposure to cadmium.
Its carcinogenic effects are evident in experimental animals and there has been
limited evidence in humans so far [15, 17]. As compared with the year 2007 there was recorded a slight increase of average annual concentration in 39 localities, in 24 localities, on the contrary, the annual average concentration decreased. The target value must be met by 31.12.2012. The development of annual average concentrations in the period of 1996–2008 is apparent from Fig. II.4.2.31. The courses of short-term (24-hour, or 14-day concentrations, according to the measurement schedule at the respective station) average cadmium concentrations in selected localities in 2008 are presented in Fig. II.4.2.33. The stations with the highest values of annual average concentrations are presented in Table II.4.2.15. Fig. II.4.2.31 Annual average concentrations of cadmium in the ambient air in 1998–2008 at selected stations
Fig. II.4.2.32 Field of annual average concentration of cadmium in the ambient air in 2008
Fig. II.4.2.33 1/14-day average concentrations of cadmium in the ambient air in 2008 at selected stations
Arsenic Arsenic occurs largely in fine fractions (aerodynamic diameter up to 2.5 μm), which can be transported over long distances and can penetrate deeply into the respiratory system. Almost all arsenic is bound to particles with aerodynamic diameter up to 10 μm [17]. Inorganic arsenic can cause acute, subacute or chronic effects (local or affecting the whole organism). Lung cancer can be considered the critical effect following inhalation exposure [15, 17]. Of the total number of 68 localities which monitored arsenic concentration in
2008 the target value (6 ng.m-3) was exceeded in 6 localities (Prague
5-Řeporyje, Kladno-Vrapice, Ostrava-Mariánské Hory, Ostrava-Bartovice,
Kladno-Švermov and Stehelčeves). This target value must be met by 31.12.2012. The development of annual average concentrations during the years 1996–2008 is apparent from Fig. II.4.2.34. The courses of short-term (24-hour, or 14-day concentrations, according to the measurement schedule at the respective station) average arsenic concentrations show the seasonal character of the short-time arsenic concentrations in the ambient air and confirm the significant arsenic contribution from the burning of fossil fuels (Fig. II.4.2.36). The stations with the highest annual average concentrations are presented in Table II.4.2.16. Fig. II.4.2.34 Annual average concentrations of arsenic in the ambient air in 1998–2008 at selected stations
Fig. II.4.2.35 Field of annual average concentration of arsenic in the ambient air in 2008
Fig. II.4.2.36 1/14-day average concentrations of arsenic in the ambient air in 2008 at selected stations
Nickel The main anthropogenic sources, which globally represent about three quarters of
total emissions, include combustion of heavy fuel oils, mining of
nickel-containing ores and nickel refinement, waste incineration and iron and
steel production. Main natural sources include continental dust and volcanic
activity. About 70 % of particles containing nickel comprise the fraction smaller than 10
μm. These particles can be transported over long distances. About 30 % of
particles containing nickel have aerodynamic diameter equal or higher than 10 μm
and quickly settle in the vicinity of the source [17]. None of the total 67 measuring localities, similarly as in previous years, exceeded the target value (20 ng.m-3) for nickel annual average concentrations. The annual average concentrations measured in Kladno-Vrapice and Stehelčeves (with relatively marked increase of concentrations as compared with the two previous years), exceeded the lower assessment threshold (10 ng.m-3). The highest annual average concentration was measured in the locality Kladno-Vrapice (11.2 ng.m-3),where the increase was approximately four times higher as compared with the two previous years. The number of localities with a slight increase of concentrations as compared with the year 2007 was the same as the number of localities with a slight decrease of concentrations. The stations with the highest values of the annual average concentrations are
presented in Table II.4.2.17. Fig. II.4.2.37 Annual average concentrations of nickel in the ambient air in 1998–2008 at selected stations
Fig. II.4.2.38 1/14-day average concentrations of nickel in the ambient air in 2008 at selected stations
II.4.2.1.8 Benzo(a)pyrene
The cause of the presence of benzo(a)pyrene, the main representative of
polycyclic aromatic hydrocarbons (PAH) in the ambient air is, similarly as in
other PAH, the insufficient burning of fossil fuels both in stationary and
mobile sources, and also some technologies, as coke and iron production.
Stationary sources are represented mainly by local heating (coal combustion).
Mobile sources are represented mainly by diesel motors. The natural background
level of benzo(a)pyrene is almost zero with the exception of wildfires [15].
When constructing the map of concentrations also emissions from transport are
taken into account in addition to the stationary sources, and namely
benzo(a)pyrene emissions from highways and main roads. The map was also created
with regard to the gradient of benzo(a)pyrene air pollution concentrations with
the altitude. The map for the year 2008 is again based directly on the emissions
from benzo(a)pyrene, not on the percentage share from PAH emissions as in the
previous years. However, it is necessary to consider that the estimates of the
fields of annual average benzo(a)pyrene concentrations, in comparison with other
mapped pollutants, bear the greatest uncertainties which result form
insufficient density of measurements. The development of annual average concentrations in individual localities during 1998–2008 is apparent from Fig. II.4.2.39. In 2008 there was the increase at the stations in Ostrava region as compared with the year 2007 (markedly at the suburban background station Ostrava-Poruba, slightly at the stations Ostrava-Bartovice, Ostrava-Přívoz and Český Těšín). The annual concentrations increased markedly also in the locality Kladno-Švermov. The stations in Plzeň, Brno and Prague (Prague 10-Šrobárova) and Ústí nad Labem (ZÚ-Pasteurova) recoreded a slight increase. The annual course of short-term concentrations (24-hour once in 3 or 6 days) of benzo(a)pyrene is presented in Fig. II.4.2.42. The fluctuations of monthly averages of concentrations for different types of stations in 2004–2008 are shown in Fig. II.4.2.41. The increase of concentrations during the winter periods confirm the influence of local furnaces. Fig. II.4.2.43 depicts benzo(a)pyrene concentrations in individual localities between 2004 and 2008 in relation to PM10 concentrations, resp. to its fine fraction PM2.5 to which benzo(a)pyrene is mainly bound. Fig. II.4.2.39 Annual average concentrations of benzo(a)pyrene in the ambient air in 1998–2008 at selected stations
Fig. II.4.2.40 Field of annual average concentration of benzo(a)pyrene in the ambient air in 2008
Fig. II.4.2.41 Month average concentrations of benzo(a)pyrene at various types of localities, 2004–2008
Fig. II.4.2.42 24-hour concentrations at the stations with the highest annual concentrations of benzo(a)pyrene in 2008
Fig. II.4.2.43 Concentrations of benzo(a)pyrene and PM10 particles in individual localities, 2004–2008
II.4.2.1.9 Other substances
Mercury Studies of occupationally exposed humans have shown adverse effects on the central nervous system and kidneys at high mercury vapour levels [18]. The increased concentrations in the ambient air result in higher atmospheric deposition on top water layers and, consequently, in higher methylmercury concentrations in freshwater fish and its accumulation in food chains. [15, 18]. In spite of the fact that the limit value for mercury has not been set yet, the Czech national legislation recommends, pursuant to the European directives, to carry out its monitoring and assessment according to the annual arithmetic mean.
In 2008 the CHMI ISKO database received data on mercury concentrations in PM10
particles in the ambient air from 2 localities in total, and namely from the
locality Karviná ZÚ where the measured annual average was (0.73 ng.m-3)
and from the locality Košetice with the annual average concentration 0.013 ng.m-3.
Ammonia
Similarly as in the case of mercury, the limit value for ammonia is not defined
in the current European and Czech legislation. Ammonia monitoring was carried
out, similarly as in the year 2007, at 4 localities. The highest annual average
concentration was measured again at the station Lovosice-MÚ (9.1 μg.m-3).
The result concentrations of pollutants in the Czech Republic and agglomerations, related to the respective years, represent average values from the stations which measured for the whole monitored period. Fig. II.4.2.44 shows the trends of SO2, PM10, NO2, NOx and O3 annual air pollution characteristics in the Czech Republic for the period of 1996–2008 and PM2.5 for the period 2004–2008. Up to the year 2000 air pollution caused by SO2, PM10, NO2 and NOx had a decreasing trend in the whole Czech Republic. In SO2 and PM10 concentrations the decline was very steep up to the year 1999. In 2001 the decreasing trend was interrupted in the whole Czech Republic and, on the contrary, a slight increase of SO2, NO2 and NOx concentrations and a significant increase of PM10 concentrations occurred. In 2004 this increasing trend of air pollution caused by PM10, NO2 and NOx finished and, on the contrary, certain decrease of these pollutants concentrations occurred, reaching almost the levels of the year 2001. In 2005 the PM10 and NO2 concentrations returned back to the increasing trend, in PM10 the increase was steeper, beyond the level of the year 2002, and also PM2.5 concentrations were increased. This increasing trend was confirmed in 2006 in NO2 and in annual PM10 concentrations (at urban stations); more significant increase was recorded in case of one-hour NO2 concentrations – it almost reached the level of the year 1997. On the contrary, 24-hour PM10 concentrations recorded a slight decrease. Annual PM2.5 concentrations stagnated. Between 2003 and 2005 a slight decrease of SO2 concentrations was observed. In 2007 the fluctuating trend of the levels of the above pollutants concentrations stopped and there was recorded a marked decrease of air pollution caused by SO2 and PM10 (both in towns and in the country), PM2.5, NO2 and NOx in all monitored air pollution characteristics. The steepest decrease is evident, after the previous increase, in hourly NO2 concentrations. In 2008 the decreasing trend of ambient air pollution caused by SO2 and PM10 continued, the PM2.5 concentrations (measured in fewer localities than PM10) more or less stagnated. As concerns NO2, there was recorded a slight decrease in daily concentrations, in NOx there was a slight decrease in annual averages at rural stations. The decrease of the above pollutants concentrations in the ambient air was given both by more favourable meteorological and dispersion conditions, mainly in April, November and December 2008, and by the decrease of total SO2 emissions, solid particles (REZZO 1) and NOx (REZZO 1 and 4) as compared with the year 2007. In ozone there is an apparent decreasing trend up to 1997. In 1998–2002 the O3 concentrations stagnated. In 2003 there is apparent the increasing trend in concentrations due to long lasting very high temperatures and high levels of solar radiation. In 2004 O3 concentrations slightly decreased below the level from the years 1997–2002, in 2005 they amounted slightly above the level from 1997–2002. In 2006 the concentrations slightly increased. In 2007 the average from the 26th highest maximum 8-hour running averages slightly decreased. On the contrary, there was a slight increase of the 76th values of maximum 8-hour running averages for the previous 3 years, resulting mainly from the fact that the April–September period of the year 2007 was warmer (in the average for the whole Czech Republic by 1.2 C ) than the year 2004 which was included in the previous three-year period but not taken into account for the assessment of the 2005–2007 period. In the period 2006–2008 the 76th highest value of maximum 8-hour running averages decreased, probably due to the decrease of the precursors concentrations (both NOx and VOC). This decrease is visible in the graph of the trends in all types of localities; also apparent is the decrease of concentrations in the year 2008 itself. The graphs of trends show apparently higher concentrations in rural localities as compared with the concentrations from urban and suburban localities, where ozone is removed mainly by emissions from traffic. Fig. II.4.2.44 Trends of SO2, PM10, PM2.5, NO2, NOx and O3 annual characteristics in the Czech Republic, 1996–2008
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