 |
AIR POLLUTION IN THE CZECH REPUBLIC IN 2009 Czech Hydrometeorological Institute - Air Quality Protection Division |
|
|
|
|
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 2009 the set limit value for 24-hour SO2 concentration (125 μg.m-3) was exceeded at the Teplice-ZÚ station 12x in total. The tolerated number of exceedances is 3). This was caused mainly by the episode of increased concentrations in late November/early December 2009. It is almost certain that in this case there was a smoke plume influence from local heating and we cannot relate it with the total air pollution situation caused by SO2 in the city. No other locality recorded the exceedance of the 24-hour limit value, only AIM Teplice exceeded the value 125 μg.m-3 within the tolerated number. No locality reported the exceedance of the 1-hour SO2 limit value 350 μg.m-3 (the set tolerated number of exceedances is 24 per year). The highest number of exceedances of the value 350 μg.m-3 was recorded at the AMS station Lom – 4x). The 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 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 stopped in 2009 and, on the contrary, SO2 concentrations slightly increased. We suppose that certain increase of SO2 concentrations occurred also 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. Figs. II.4.2.3 and II.4.2.4 document the courses of 1-hour and 24-hour SO2 concentrations at the stations in 2009. Fig. II.4.2.2 presents the spatial distribution of the 4th highest 24-hour SO2 concentration. On 1.4 % of the territory of the Czech Republic the SO2 concentrations exceeded the lower assessment threshold (LAT). This confirms the slight increase of air pollution caused by SO2 as compared with the previous year. The map shows an apparent increase of ambient air pollution in the Ústí nad Labem Region. The map for the year 2009 defines for the first time also the class of concentrations up to 20 μg.m-3 (guide value of the WHO = 20 μg.m-3).
Tab. II.4.2.1 Stations with the highest values of the 25th and maximum hourly
concentrations of SO2
Fig. II.4.2.1 4th highest 24-hour concentrations and 25th highest hourly
concentrations of SO2 in 1999–2009 at selected stations
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. In 2009 there prevailed a slight increase, more marked in the Ostrava area. 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 2009, and namely at the stations in the Moravian-Silesian Region: Bohumín, Věřnovice, Český Těšín, Ostrava-Bartovice, Ostrava-Přívoz, Orlová, Karviná, Havířov, Ostrava-Českobratrská (hot spot), Karvíná-ZÚ, Ostrava-Fifejdy, Ostrava-Zábřeh; at the stations of the South-Moravian Region: Brno-Svatoplukova, Brno-Zvonařka and Brno-střed; of the Central Bohemian Region: Stehelčeves and Kladno-Švermov; of the Olomouc Region: Šumperk MÚ; of the Ústí nad Labem Region: Lom, Děčín and Most; of the Zlín Region: Uherské Hradiště; of theSouth Bohemian Region: Tábor; and at the stations of the capital city of Prague: Prague 5-Smíchov and Prague2-Legerova. Of the total number of 148 localities in which PM10 measurements were carried out, 50 stations reported exceedances of 24-hour PM10 limit value (in 2008 47). The annual PM10 limit value was exceeded at 14 stations (in 2008 at 15), the highest annual averages were recorded in two localities of the Moravian-Silesian Region:. Věřňovice (53 μg.m-3) and Bohumín (53 μg.m-3). As it is evident from Fig. II.4.2.6, in 2009 there was certain enlargement of
the area with above-the-limit 24-hour concentrations of PM10 in the Olomouc
Region, Moravian-Silesian Region, Ústí nad Labem Region and the Central Bohemian
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 2009 the respective limit values for PM10 were exceeded in 4.4 % of the territory of the Czech Republic with approx. 18 %
of inhabitants. 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 2005–2009 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 annual 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 2009 the measurements were carried out in 36 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 limit 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 10 localities the limit value was exceeded (9 in 2008). These are the stations in the Ostrava-Karviná area (Bohumín, Věřňovice, Ostrava-Přívoz, Ostrava-Bartovice, Ostrava-Zábřeh, Ostrava-Poruba/CHMI and Třinec-Kosmos), in Brno (Brno-Svatoplukova and Brno-Zvonařka) and in the Olomouc Region (Přerov). 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 2009 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 2004–2009 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 limit 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, in the territory of the city of Brno and the Olomouc Region. Fig. II.4.2.14 shows the seasonal course of the ratio between PM2.5 and PM10 fractions. It is the month average of the ratio of PM2.5 and PM10 daily concentrations from the stations which had sufficient valid data for each month of the year 2009 (they had valid monthly average). The measurement results indicate that the ratio between PM2.5 and PM10 is not constant but shows certain seasonal course and, simultaneously, it is dependent on the locality classification and position. In 2009 the ratio, in the average from about 30 stations in the Czech Republic (simultaneously measuring PM2.5 and PM10 and with sufficient number of values, ranged from 0.65 (July) to 0.8 (February) with lower values in the summer period. In Prague, where the annual course is influenced by a large share of traffic stations, this ratio was from 0.55 (November) to 0.75 (February), in Brno 0.66 (May, June, July) to 0.86 (January), in the Ústí nad Labem Region 0.6 (July, August, September) to 0.75 (February) and in the Moravian-Silesian Region 0.68 (June) to 0.85 (January). When comparing the ratio with regard to the classification of stations, the ratio in urban stations is 0.62 (June, July) to 0.79 (January), in suburban stations 0.68 (July) to 0.82 (January, December), and traffic stations 0.5 (November) to 0.76 (February). It should be taken into account that the number of stations with simultaneous measurement of PM2.5 and PM10 is not sufficient. 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 Fig. II.4.2.5 36th highest 24-hour concentrations and annual average
concentrations of PM10 in 1999–2009 at selected stations
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 179 localities in which NO2 was monitored in 2009 the annual limit value was exceeded at 11 stations (Table II.4.2.9). The limit value plus the margin of tolerance (42 μg.m-3) was exceeded at 9 localities, and namely at 3 stations in Prague (Prague 2-Legerova (hot spot station), Prague 5-Svornosti and Prague 8-Sokolovská), at 3 localities in Brno (Brno-Úvoz (hot spot station), Brno-střed and Brno-Svatoplukova), in two localities in the Ústí nad Labem Region (Ústí n.L.-Všebořická (hot spot station) a Děčín-ZÚ) and in one locality 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 Prague 2-Legerova, aimed at ambient air pollution monitoring caused by traffic, recorded, similarly as in the previous years, a great number of exceedances (98) of the limit value for NO2 hourly concentration 200 μg.m-3. In 2009 this AMS exceeded also the hourly limit value plus the margin of tolerance 210 μg.m-3 (67x). Nevertheless, the admissible exceedance frequency is 18. 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 2009, on the contrary, most stations recorded a slight increase of NO2 concentrations. The field of NO2 annual average concentration (Fig. II.4.2.17) gives evidence of air pollution in the cities caused mainly by traffic. For the first time the map defines also the lowest class of concentrations up to 13 μg.m-3. Figs. II.4.2.18 and II.4.2.19 show the graphs of the courses of daily and hourly concentrations in 2009 showing the evident limit value (LV) exceedances in localities. 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 5 years, the increase of traffic volume 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 Fig. II.4.2.16 19th highest hourly concentrations and annual average
concentrations of NO2 in 1999–2009 at selected stations Fig. II.4.2.17 Field of annual average concentration of NO2 in 2009
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 2009 carbon monoxide concentrations were measured at 37 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 the previous two years, at the hot spot locality Ostrava-Českobratrská (4,912.1 μg.m-3). Unlike the years 2006 and 2008 even the lower assessment threshold was not 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 2009 is characterized in Table II.4.2.10. Fig. II.4.2.20 Maximum daily 8-hour running average concentrations of CO in
1999–2009 at selected stations 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 2009 benzene concentrations were measured in total in 27 localities with valid annual average. The limit value is defined as an annual average concentration 5 μg.m-3. This limit must have been achieved by 31.12.2009. The margin of tolerance for the year 2009 reached the value of 1 μg.m-3. The highest annual average concentration in the Czech Republic in 2009 (5.7 μg.m-3) was measured in the CHMI locality Ostrava-Přívoz, similarly as in 2008 (6.7 μg.m-3) and 2007 (8 μg.m-3). The limit value in this locality was exceeded again in 2009, 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 against 2008, was comparable with the number of localities with a slight increase. The diagram map (Fig. II.4.2.22) shows the overview of the development of average annual concentrations in 1999–2009. Fig. II.4.2.24 presents the annual course of 24-hour averages in selected localities. 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 1999–2009 at
selected stations
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 2009 ozone was measured at 73 localities out of which 20 (27.4 %) exceeded the target value for the three-year period 2007–2009, or shorter (see Table II.4.2.12). In two localities (Teplice, Jeseník) the target value was achieved, the number of exceedances of the level 120 μg.m-3 was equal to the maximum admissible cases, i.e. 25. The maximum number of exceedances was recorded in the locality Štítná n.Vláří, where the average number of exceedances of the maximum daily 8-hour running average 120 μg.m-3 reached the value of 57.7. The comparison of the assessed three-year 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 usually measured. In comparison with the previous three-year period 2006–2008 the number of exceedances of the target value 120 μg.m-3 markedly decreased in most localities (64 in total). Significant improvement of the situation in average for 3 years is apparent from the Fig. II.4.2.26. The share of the area, in which the target value was not exceeded, increased from 6.2 % of the Czech Republics territory (for the period 2006–2008) to almost 53 % of the territory (for the period 2007–2009). As compared with the previous assessed three-year periods, this represents a significant decrease in ozone pollution. In the year 2006, which was not included in the three-year period 2007–2009 assessed in 2009, the average number of exceedances of the target value (120 μg.m-3) was 34.2. In 2009 the average number of exceedances was only13.3. When comparing the meteorological conditions in 2006 and 2009 to detect the causes of the improvement of ambient air pollution situation, there is only a slight decrease of maximum temperatures (99.9th percentile of hourly temperatures measured in AIM localities) in 2009. More marked differences in the average temperature during April–September of 2006 and 2009, i.e. during the period when the highest ozone concentrations are usually measured, were not recorded. The values of solar radiation were also similar in the two years. At several stations (about 20), at which during the previous three-year period 2006–2008 the 26th highest maximum daily 8-hour running average reached the values only slightly above 120 μg.m-3/125 μg.m-3, there was recorded a slight decrease below 120 μg.m-3/115 μg.m-3 in the period 2007–2009, which partly contributed to significant reduction of the territory of the Czech Republic with exceedances of the target value, though the absolute decrease of concentrations was not too significant at these stations. The decrease was probably caused, apart from a slight decrease of maximum temperatures, also by a slight decrease of the concentrations of ozone precursors. According to preliminary data the emission precursors in 2009, probably due to economical crisis, decreased to a certain extent as compared with the year 2006. NO2 concentrations decreased in 2009 as compared with 2006 in 88 % of the stations. The formation of ground-level ozone is also influenced by the contributing
volatile organic compounds. The concentrations of some of 30 volatile organic
compounds, monitored at the stations Prague 4-Libuš and Košetice, decreased,
some of them increased in 2009 as compared with the year 2006. The number of
compounds with increased concentration was comparable with the number of
compounds with decreased concentrations. The diagram map in Fig. II.4.2.25 shows the 26th highest value of maximum 8-hour running average of ozone concentrations (three-year average) in 1999–2009. 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 period of 1995–2009.
Tab. II.4.2.12 Stations with the highest values of maximum
daily 8-hour running average concentrations of ozone
Fig. II.4.2.25 26th highest values of maximum daily 8-hour running average of
ground-level ozone concentrations (three-year average) in 1999–2009 at selected
stations
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 67 localities measuring lead concentrations 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 2009 the highest concentration was reached in the locality Ostrava-Mariánské Hory (70.7 ng.m-3). In the previous two years the maximum values were measured in the locality Ostrava-Bartovice. 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). As compared with the year 2008 there was a slight decrease in 48 localities and 17 localities recorded a slight increase. The 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. The stations with the highest values of annual average concentrations are presented in Table II.4.2.14. Fig. II.4.2.29 Annual average concentrations of lead in the ambient air in
1999–2009 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]. In 2009 cadmium concentrations were monitored in 67 localities in total. None of them exceeded the target value (5 ng.m-3). The highest annual average was measured in the locality Souš (3.5 ng.m-3). The increase of concentrations in Ostrava recorded in 2008 was not confirmed in 2009. As compared with the year 2008 there was recorded a slight decrease of average annual concentration in approximately two thirds of localities; in 22 localities, on the contrary, it increased. The target value should be met by 31.12.2012. The development of annual average concentrations in the period of 1999–2009 is
apparent from Fig. II.4.2.31. Fig. II.4.2.31 Annual average concentrations of cadmium in the ambient air in
1999–2009 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 67 localities which monitored arsenic concentration in 2009 the target value (6 ng.m-3) was exceeded in 2 of them (Ostrava-Mariánské Hory and Kladno-Švermov). In the locality Ostrava-Bartovice the annual average reached the target value. This target value should be met by 31.12.2012. The marked increase of the number of localities with exceedances recorded in 2008 (6 in total) did not continue in 2009. The Ostrava stations recorded the exceedances also in the previous years. The exceedances occurred already in three latest years also in the locality Kladno-Švermov. In Prague, at the Prague 5-Řeporyje station, the annual average increased gradually over the period 2004–2008, and the target value was exceeded in 2007 and 2008. In 2009 the annual average concentration was again below the limit value (3.5 ng.m-3). In comparison with the year 2008 the number of localities with arsenic target value exceedances decreased (from 6 to 2), nevertheless both the increase and decrease of the annual average was recorded in the comparable number of localities. The development of annual average concentrations during the years 1999–2009 is
apparent from Fig. II.4.2.34. 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
1999–2009 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. Nickel occurs in the atmospheric aerosol in several chemical compounds which differ by its toxicity for human health and ecosystems. 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]. The health effects include allergic dermatitis and there is evidence of nickel
carcinogenicity for humans [15, 17]. 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
1999–2009 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]. In 2009 benzo(a)pyrene concentrations were monitored in 34 localities; 21 of them exceeded the target value of 1 ng.m-3 (annual average concentrations). In Teplice the annual average reached the level of the target value. The highest annual average concentration was measured, similarly as in the previous years, in Ostrava-Bartovice (9.2 ng.m-3), where the target value was exceeded more than 9x. The measured concentrations in 2009 were similar as in the previous year. In comparison with the year 2008 the annual average concentrations decreased as well as increased in approximately same number of localities. It is necessary to consider that the estimates of the fields of annual average benzo(a)pyrene concentrations, in comparison with other mapped pollutants, are loaded with the greatest uncertainties which result form insufficient density of measurements. A number of towns and villages were assessed, similarly as in the previous years, as the areas with the exceeded target value. In 2009 the target value was exceeded in 1.7 % of the territory of the Czech Republic, in 2008 it was 3.6 %. The target value for benzo(a)pyrene should be met by 31.12.2012.
Fig. II.4.2.39 Annual average concentrations of benzo(a)pyrene in the ambient
air in 1999–2009 at selected stations
II.4.2.1.9 Other substances
Mercury The natural sources (representing about 60 % of total emissions) include mainly mercury evasion from aquatic ecosystems and vegetation, volcanic activity and de-gassing from mercury-rich minerals. As for anthropogenic emissions it is estimated that in Europe approximately 60 % of mercury is emitted in the form of elemental vapour Hg0, 30 % as divalent mercury (Hg (II)), and only 10 % as particulate phase mercury (Hg(p)). Most emissions from natural sources are in gaseous form Hg0 [18]. 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 2009 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 Ústí nad Labem-město where the annual average was measured (5.8 ng.m-3) and from the locality Košetice which did not achieve the sufficient data for the calculation of the annual average. Table II.4.2.19 presents the overview of the stations measuring mercury in the ambient air and the annual average and maximum 24-hour concentrations.
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 previous years, at 4 localities. The highest annual average concentration was measured again at the station Lovosice-MÚ (7.9 μg.m-3). Table II.4.2.20 presents the overview of stations measuring ammonia in the ambient air and annual average and maximum 24-hour concentrations.
The result concentrations of pollutants in the Czech Republic and also in 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 1996–2009 and PM2.5 for the period 2004–2009. 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 fluctuation of the trends of individual pollutants is caused on the one hand by the decline of emissions, the change of the structure of industrial production and of the used fuels; on the other hand there is a significant influence of meteorological conditions, particularly dispersion conditions. In 2009, on the contrary, there was a marked increase of air pollution caused by SO2, PM10, NO2 and NOx roughly to the level of the year 2007 in all these pollutants (except for PM2.5). The increase of the above pollutants concentrations in the ambient air was given by less favourable meteorological and dispersion conditions, mainly in January, February and December 2009 as compared with the year 2008. 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 alone. The decline of ozone concentrations continued also in the period 2007–2009, when there was a marked decrease of the number of exceedances of the limit value 120 μg.m-3 in most localities, and, as it is apparent from the graph, the 26th highest value of the maximum 8-hour running average decreased for the year 2009 alone, as well as the average for 3 years. The graphs of trends also 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,
1996–2009
|
