On 1 June 2002 new Clean Air Act came into force (covering air quality protection and the change of some other laws) [9] and Regulation of the Government of the Czech Republic setting new air pollution limit values came into force on 14 August 2002 [10]. The new legislation fully reflects the requirements of the European Union set by the ambient air quality directives. This part of the Yearbook presents air quality assessment in 2001 with regard to the requirements of the newly implemented legislation. The application of the new limit values based on the above Regulation can be fully used for the 2002 data, nevertheless in the EU member states the respective directives, on which the above Regulation is based, are applied for the situation in 2001. It can be expected that the candidate countries will be asked to carry out similar analysis of the 2001 situation in spite of the fact that the new national legislation was not in force.

Air quality assessment pursuant to the new legislation reassumes the results and mainly methods developed within the research project VaV740/2/00 �Evaluation of the Czech Republic Readiness to Meet Air Quality Requirements of EU Directives and the LRTAP Convention� [11], especially in its stage aimed at the classification of the territory reflecting the requirements set by the newly introduced legislation – Clean Air Act. The evaluation was based on the standards and requirements on air quality assessment set by the Council Directive 96/62/EC [12] on ambient air quality assessment and management and the follow-up Directive 99/30/EC [13] relating to limit values for sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter and lead in ambient air, Directive 2000/69/EC [14] of December 2002, setting up the limit values for carbon monoxide and benzene, and finally on the Directive 2002/3/EC [15] setting up the limit values for ozone. Apart from the mentioned pollutants the new legislation brings also the stricter limit value for cadmium in comparison with the present national limit value. The Regulation introduces also the limit value for the protection of health for ammonia, arsenic, nickel, mercury, benzo(a)pyrene and SPM. SPM assessment could not be carried out within the presented surveys for the lack of data. Similarly, the assessment of air pollution caused by benzene, benzo(a)pyrene and primarily ammonia and mercury faced the same problem.

The complete results of the solution of the above mentioned project were uploaded on the CHMI websites. Further, they were published in the journal Ochrana ovzduší [Air pollution protection] as a supplement of No. 1/2001 [16]. The English version of this supplement was prepared for the Ministry of the Environment of the Czech Republic. The results of the EU air quality directives implementation was also presented at the workshop �CAFE – Meeting the limit values� (Bruges, Belgium, September 2001). [17].

The issue of zone delineation/classification was analyzed in detail in the report on the above project solution. It was stated that the new air quality directives require that the member states should divide their territories into zones and agglomerations while the zones are understood as basic units for air quality management. The directives specify namely the requirements for the assessment – the classification of the zones with regard to air quality. The Clean Air Act covers this issue in par. 7 dealing with special air quality protection. Article 1 introduces the term �areas with deteriorated air quality�. These are areas with the exceedence of the values of one or more air pollution limits or of the target limit value for ozone, or the value of one or more limit values including the respective margins of tolerance. Special air quality protection is required in agglomerations, i.e. in inhabited areas with the population of at least 250 000, or the area with less inhabitants but where the density of population requires special measures on air quality protection.

In the areas not included into the category of deteriorated air quality, i.e. in the areas where no limit values are exceeded, it is necessary to ensure the maintenance of good air quality. This corresponds with one of the basic principles of the Directive 96/62/EC, which requires that the once reached complying air quality continues to be maintained in the future.

For the areas with deteriorated air quality the Clean Air Act in its Article 6, par. 7 sets the obligation for the regional and local authorities to develop programs aimed at the improvement of air quality for those pollutants which show limit values and margins of tolerance exceedences (in case of ground-level ozone target air pollution limit values), with the aim to reach the limit values in the deadlines set in the implementary regulations. The definition of the areas in which air pollution limit values set by the Regulation are exceeded is a necessary prerequisite for the preparation of action plans in these areas.

Therefore the assessment carried out pursuant to the recently adopted legislation has already been included in this Yearbook.

In accordance with the generally accepted interpretation in the member countries, the zone delineation is primarily to be based on the administrative division of the country to allow the zones, as administrative units, to meet the requirements of the directives for air quality assessment, reporting to the Commission, and air quality management, for example through action plans.

Agglomerations are then defined by the directives as the zones with a population of more than 250 000, or less than that but having such population density per km², which justifies the necessity to assess and manage air quality in the area.

2.3.1 Mapping air quality characteristics required by the legislation

The adopted legislation takes over general approaches of air quality assessment and potential exceedences of the set limit values in the zones from the Framework Directive 96/62/EC for air quality management with the aim to reach in the set deadlines air quality complying with the limit values and air pollution targets. The Directive specifies that in areas over the UAT, measurement is decisive for determining pollution levels. Pollution levels must be determined for the whole zone rather than covering the mere surroundings of the station. The problem of air quality assessment in zones – particularly identifying and locating areas within the zone in which limit values may be exceeded, based on station measurements – therefore becomes a problem of estimating (throughout the zone) the distribution of air quality; it consists in how to generalise �point� measurements, given the particular density of stations and an acceptable error of the estimate, to the entire zone under review. The spatial coverage of measurements can be increased by validation measurements. However, the ambient air quality directive and consequently, the new legislation, do not stipulate measurements any longer as the only tool for determining levels in a zone, and envisages – depending on pollution levels – the use of modelling techniques and expert estimates and their combinations. An advantage of modelling is that in comparison with point measurements it better reflects the coverage of the area under review; nevertheless, models are generally regarded as less accurate than measurements. During the above mentioned workshop in Bruges, Belgium (September 2001), devoted to the first results of air quality assessment in the EU member states, a number of contributions stated that the most reliable estimate of spatial distribution for the purposes of air quality classification in the zones with regard to the directives, is based on the procedures of assimilation of the measured data and the results of modelling. Under modelling mainly causal dispersion and transport models are understood, including chemical transformations of the pollutants. An important role is played also by empirical, mathematical-statistical models of the estimate of time or spatial distribution of air pollution characteristics.

As part of regular air quality assessment, the Air Quality Information System has been using various combinations of measurements and modelling for creating fields of ambient air pollution characteristics, and these techniques are being further improved.

One of the important preconditions for creating fields of concentrations is a careful selection of the measuring stations included in the assessment, from the perspective of their use, classification and representativeness. Linear regression of the dependence of the two approaches (modelling and measurement) was applied when producing final information for map compilation in the assimilation of modelled and measured data, while a modified version of IDW, with the station�s weight and determination of its representative surroundings factored in, was applied to create the resulting fields. The basic approach to determine the degree of representativeness is station classification. Background stations (rural or urban background) with a high degree of representativeness (dozens of kilometres) are stations affected only by remote sources, while to describe local conditions also such stations exposed to traffic and industry are taken into account the least area of representativeness of which is directly affected by local sources.

The details of the mapping procedures of the respective air pollution characteristics for the pollutants set in the directives 99/30/EC (SO₂, suspended particles – PM₁₀ fraction, NO₂ and NO_x, lead), 2000/69/EC (CO and benzene) and 2002/3/EC (ozone) were published in the reports on the above project VaV740/2/00. Mapping procedures of air pollution characteristics of further substances required by the new legislation (cadmium, arsenic, nickel, mercury and benzo(a)pyrene), including further development of mapping air pollution characteristics of PM₁₀ and benzene are solved within the current CHMI project VaV/740/3/02 Integrated air quality assessment and management with regard to the daughter directives on heavy metals, PAHs, PM₁₀ and benzene.

2.3.2 Air quality with regard to health protection limit values

In accordance with the EU legislative documents on air quality the new national legislation sets the limit values aimed at health protection derived from the WHO recommendation. The new legislation requires to monitor and assess the following pollutants, as substances manifesting evident harmful effects on the health of the population, with regard to the health protection limit values:

a) sulphur dioxide
b) suspended particles – PM₁₀ fraction
c) nitrogen dioxide
d) lead
e) carbon monoxide
f) benzene
g) ozone
h) cadmium
i) arsenic
j) nickel
k) mercury
l) benzo(a)pyrene
m) ammonia.

The survey of the limit values, margins of tolerance for the protection of health, and UAT and LAT according to the Regulation shows the Table 2.3.1. These limit values, including the UAT and LAT have been set by the legislation as the levels for air quality assessment. The maps and charts presented below use the indication of the respective limit values as shown in Table 2.3.1.

The following assessment of individual pollutants relevant for health protection is presented in the order corresponding with the above list (and Table 2.3.1). It is documented mainly by the tables showing the stations with the highest values of air pollution characteristics required by the legislation for the given pollutants. The survey contain all the stations at which the limit value was exceeded (lines with light grey background), or the limit value including the margin of tolerance (lines with dark grey background). If the number of stations where the limit, or the limit incl. the margin of tolerance, was exceeded, is lower than 10, 10 stations with the highest values of the respective air pollution characteristics are presented. Further, maps depicting the development of the respective characteristics in the period 1992–2001 are presented. The 2001 exceedence of the limit value increased by the margin of tolerance is marked with red names of the stations.

Tab. 2.3.1 Survey of limit values, margins of tolerance and UAT and LAT for the protection of health according to the Regulation

If in 2001 any characteristic of the respective pollutant was exceeded, also maps depicting the spatial distribution of the characteristic are presented. These maps show also the stations classified according to their type and marked with colour symbols in correspondence with the classes of the levels measured at the presented stations.

For the stations and air pollution characteristics, where the number of exceedences incl. the margin of tolerance was higher than it is allowed, the courses of 24-hour or hourly concentrations in 2001 are presented for the indication of the period of the year during which the limit values were exceeded.

Sulphur dioxide

The 2001 situation of air pollution caused by SO₂ with regard to the limit values set by the new legislation (as shown in Table 2.3.1) is documented by the Tables 2.3.2, 2.3.3 and 2.3.4 and Figs. 2.3.1, 2.3.2, 2.3.3 and 2.3.4. It is evident from Figs. 2.3.1 and 2.3.4 that in 2001 the set limit value for 24-hour SO₂ concentration 125 μg.m^-3 was exceeded more than 3x only at Teplice-OHS station. The annual SO₂ limit value was not exceeded at any station in 2001. Similarly, no station reported the exceedence of the allowed number of exceedences of hourly SO₂ concentrations (500 μg.m^-3). The highest number of exceedences of the hourly limit value was recorded at Pardubice-Dukla station (11x, Fig. 2.3.3).

The map diagrams in Fig. 2.3.1 show the distinct 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 after the year 1997.

Figs. 2.3.3 and mainly 2.3.4 should, in compliance with the requirements of the Framework Directive, document the exceedence episodes. Fig. 2.3.4 shows the deteriorated situation in the environs of the station Teplice-OHS in the second half of the year 2001, when the 24-hour concentrations exceeded the set limit value of 125 μg.m^-3 in 14 cases.

Fig. 2.3.2 presenting the spatial distribution of the 4th highest 24-hour SO₂ concentration and the Tables 2.3.2 and 2.3.4 show that air pollution caused by SO₂ did not exceed, with the exception of a limited locality of the Teplice-OHS station, the air pollution limit values for the protection of health. With the above exception the pollution caused by SO₂ is not the reason to list any part of the territory among the areas with deteriorated air quality.

Tab. 2.3.2 Stations with the highest numbers of exceedences of the hourly limit value (pLV) and hourly limit value including the margin of tolerance (pLV + MT) of SO₂

Tab. 2.3.3 Stations with the highest numbers of exceedences of the 24-hour limit value (pLV) of SO₂

Tab. 2.3.4 Stations with the highest values of annual average concentrations of SO₂

Fig. 2.3.1  4th highest 24-hour concentrations and annual average concentrations of SO₂ in 1992-2001 at selected stations

Fig. 2.3.2 Field of the 4th highest 24-hour concentration of SO₂ in 2001

Fig. 2.3.3 Stations with the highest hourly concentrations of SO₂ in 2001

Fig. 2.3.4 Stations with the highest 24-hour concentrations of SO₂ in 2001

Suspended particles, PM₁₀ fraction

Air pollution caused by PM₁₀, as shown in the Tables 2.3.5 and 2.3.6, similarly as in Fig. 2.3.5, remains one of the main problems of air quality assurance with regard to the requirements and deadlines of the new legislation and the respective EU directive.

The limit value of 24-hour PM₁₀ concentration increased by the margin of tolerance was exceeded more than 35x, and namely at the stations: Bohumín, Věřňovice, Orlová, Český Těšín, Karviná and Havířov (Karviná district), Švermov (Kladno district), Přívoz, Radvanice and Zábřeh (Ostrava-město district). Of the total number of 119 stations at which PM₁₀ measurements are carried out, 47 stations reported exceedences of 24-hour PM₁₀ limit value, while 12 stations of them reported also exceedences of the limit value including the margins of tolerance.

Figs. 2.3.6 and 2.3.7 show that PM₁₀ limit values exceedences are significant for listing the respective areas among the areas with deteriorated air quality. Limit values for 24-hour PM₁₀ concentrations were exceeded more than 35x mainly in Moravian-Silesian, Ústí nad Labem, Central Bohemian and Olomouc Regions and in Prague also in 2001. The areas where PM₁₀ concentrations exceed the respective limit values represent more than 3.4 % of the territory of the Czech Republic with more than 25 % of the total population.

The courses of 24-hour concentrations in 2001 at the stations, where the limit values including the margin of tolerance were exceeded, are shown in Fig. 2.3.8.

Tab. 2.3.5 Stations with the highest numbers of exceedences of the 24-hour limit value of PM₁₀

Tab. 2.3.6 Stations with the highest values of annual average concentrations of PM₁₀

Fig. 2.3.5 36th highest 24-hour concentrations and annual average concentrations of PM₁₀ in 1992-2001 at selected stations

Fig. 2.3.6 Field of the 36th highest 24-hour concentration of PM₁₀ in 2001

Fig. 2.3.7 Field of annual average concentration of PM₁₀ in 2001

Fig. 2.3.8 Stations with the highest 24-hour concentrations of PM₁₀ in 2001

Nitrogen dioxide

The exceedence of annual limit values for NO₂ occurred only in limited number of localities exposed to traffic in agglomerations and large cities. Of the total number of 129 stations at which NO₂ was monitored in 2001 the annual limit value of 40 μg.m^-3 was exceeded only at 3 stations in Prague (nám. Republiky, Mlynářka, Vršovice). No station reported the exceedence of margins of tolerance.

Hourly concentrations of NO₂ (Table 2.3.7) do not exceed the allowed exceedence frequency at any station. In 2001 the highest value of the 19th maximum hourly NO₂ concentration (114 μg.m^-3) was recorded at the station Praha 1-nám. Republiky.

The annual NO₂ limit values are regularly exceeded mainly in Prague at the stations monitoring the effects of traffic on urban environment (Praha 1-nám. Republiky, Praha 10-Vršovice, Praha 5-Mlynářka and Praha 5-Smíchov).

At most stations presented in Fig. 2.3.9 both the annual average concentration and the 19th highest hourly CO₂ concentration have a moderately declining trend in recent five years corresponding with the fact that NO_x emissions from transport have stagnated in recent years due to the increasing number of vehicles with catalytic converters, and the fact that emissions from stationary sources have been declining.

Tab. 2.3.7 Stations with the highest values of the 19th and maximum hourly concentrations of NO₂

Tab. 2.3.8 Stations with the highest values of annual average concentrations of NO₂

Fig. 2.3.9 19th highest hourly concentrations and annual average concentrations of NO₂ in 1992-2001 at selected stations

Fig. 2.3.10 Field of annual average concentration of NO₂ in 2001

Fig. 2.3.11 Stations with the highest hourly concentrations of NO₂ in 2001

Lead

The source of air pollution caused by lead are primarily the means of transport using leaded petrol. Further, it is caused by high-temperature processes, primarily the burning of fossil fuels and metallurgy of non-ferrous metals.

None of the total number of 85 stations monitoring lead in the ambient air in 2001 reported the exceedence of the set limit value. The highest concentration was reached at the station Český Těšín (Karviná district), and namely 86 ng.m^-3. Table 2.3.9 shows that lead concentrations at all stations are under the limit value and do not even reach the LAT (250 ng. m^-3). It is apparent from Fig. 2.3.12 that lead levels at the majority of stations do not reach LAT in the long terms and have a decreasing trend. Courses of 7/14-day average concentrations of lead (Fig. 2.3.13) show the seasonal character of short-time lead concentrations in the ambient air indicating the significant contribution of lead to the ambient air caused by burning fossil fuels, especially in the environs of the presented stations.

Tab. 2.3.9 Stations with the highest values of annual average concentrations of lead in the ambient air

Fig. 2.3.12 Annual average concentrations of lead in the ambient air in 1992-2001 at selected stations

Fig. 2.3.13 7/14-day average concentrations of lead in the ambient air at selected stations in 2001

Carbon monoxide

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.

Maximum 8-hour moving averages of carbon monoxide (Tab. 2.3.10 and Figs. 2.3.14 and 2.3.15) do not exceed the limit values, with the exception of the HS stations Praha-8 Sokolovská and Praha 5-Svornosti where the limit values are exceeded including the margins of tolerance. At most stations the recorded averages are even under the LAT level. Of the total number of 54 stations measuring carbon monoxide 2 stations reported the exceedence of the limit value including the margin of tolerance, and one station (Praha 5-Řeporyje) reported the exceedence of the limit value.

Carbon monoxide monitoring requires, due to the repeated exceedences of limit values including the margins of tolerance at the presented HS stations in Prague, the improving of the system of assurance of measurement accuracy and namely the assurance of comparability of the measured data supplied by individual organizations contributing to the ISKO database.

Tab. 2.3.10 Stations with the highest values of maximum 8-hour moving average concentrations of CO

Fig. 2.3.14 Maximum 8-hour moving average concentrations of CO in 1992-2001 at selected stations

Fig. 2.3.15 Stations with the highest values of maximum 8-hour moving average concentrations of CO in 2001

Benzene

With the increasing intensity of road transport the monitoring of air pollution caused by aromatic hydrocarbons is becoming relevant. The decisive source of atmospheric emissions of aromatic hydrocarbons – and namely of benzene and its alkyl derivates – are above all exhaust gases of petrol motor vehicles. Another source are loss evaporative emissions produced during petrol handling, storing and distribution. Mobile sources emissions account for approx. 85 % of total aromatic hydrocarbons emissions, while the prevailing share is represented by exhaust emissions. It is estimated that the remaining 15 % of emissions come from stationary sources. Many of these are related to industries producing benzene and those industries that use benzene to produce other chemicals.

The obtained data illustrate that benzene level in petrol is about 1.5 % while diesel fuels contain relatively insignificant levels of benzene. Exhaust benzene is produced primarily by unburned benzene from fuels. Non-benzene aromatics in the fuels can cause 70 to 80 % of the exhaust benzene formed. Some benzene also forms from engine combustion of non-aromatic fuel hydrocarbons.

Recent assessment based on measurement results indicate that limit values including the margins of tolerance of benzene annual concentrations were exceeded in Ostrava. The estimates of empirical modelling show the exceedences of benzene limit values in Prague, at sites exposed to traffic (Table 2.3.11 and Figs. 2.3.16 and 2.3.17). Situation of the year 2001 is characterized in the Table 2.3.11. Of 10 stations monitoring benzene and other aromatic hydrocarbons in the territory of the Czech Republic the benzene limit value was exceeded at two neighbouring stations in Ostrava influenced by near by industrial sources.

It is necessary to enlarge the benzene measurements in agglomerations and other cities exposed to traffic pursuant to the requirements of the new legislation.

Tab. 2.3.11 Stations with the highest values of annual average concentrations of benzene

Fig. 2.3.16 Annual average concentrations of benzene in 1992-2001 at selected stations

Fig. 2.3.17 24-hour concentrations at the stations with the highest annual benzene concentrations in 2001

Ground-level ozone

Ground-level ozone is a result of complex physiochemical processes, during which ozone is formed under the influence of solar radiation from ozone precursors – NO_x and VOC.

In 2001 the air pollution target value was exceeded at 22 stations, out of 56 stations which submitted valid data (Table 2.3.12).

Map diagram in Fig. 2.3.18 illustrates that at more than 30 stations the maximum 8-hour concentrations for the given year in the period 1992–2001 have a decreasing character. On the contrary, at 10 urban stations this trend is increasing. This is in accordance with the records of O₃ air pollution characteristics at the stations in western Europe where rural stations report the decrease of maximum 8-hour concentrations in connection with the decrease of NO_x and VOC emissions. On the contrary, urban stations show an increasing trend.

The ozone target limit for the protection of health is thus exceeded in more than 70 % of the Czech Republic�s territory (Fig. 2.3.19).

Tab. 2.3.12 Stations with the highest values of maximum daily 8-hour moving average concentrations of ozone

Fig. 2.3.18 26th highest values of maximum 8-hour moving average of ozone concentrations in 1992-2001 at selected stations

Fig. 2.3.19 Field of the 76th highest maximum daily 8-hour moving ozone concentration in 1999-2001

Fig. 2.3.20 Stations with the highest values of maximum daily 8-hour moving average concentrations of ozone in 2001

Cadmium

The anthropogenic sources of cadmium in the ambient air are: high-temperature processes, especially burning fossil fuels, primarily coal containing cadmium components, then incinerators, metallurgy of non-ferrous metals, glass industry and the production of cement.

The limit value 5 ng.m^-3 as the annual average concentration is exceeded at the stations Tanvald (HS) and Souš (CHMI) in Jablonec nad Nisou district in the long terms. At the stations in Ostrava the cadmium concentrations ranged around the limit value. High concentrations in the given localities are confirmed also by the results of the modelling of cadmium emission dispersion.

In 2001 cadmium in the ambient air was monitored at 78 stations, out of which 1 reported exceedences of the limit value including the margin of tolerance (8 ng.m^-3) and 2 further stations reported the exceedence of the air pollution limit value for cadmium.

Tab. 2.3.13 Stations with the highest values of annual average concentrations of cadmium in the ambient air

Fig. 2.3.21 Annual average concentrations of cadmium in the ambient air in 1992-2001 at selected stations

Fig. 2.3.22 Field of annual average concentration of cadmium in the ambient air in 2001

Arsenic

The origin of anthropogenic ambient air pollution caused by arsenic is represented by burning fossil fuels, primarily coal containing traces of arsenic components (up to 87 %).

Of the total number of 86 stations which submitted valid data for 2001 the new limit value was exceeded at 4 stations, especially in the Ostrava-město and Karviná districts and at the station Tanvald in the district Jablonec nad Nisou (Table 2.3.14). Map diagram in Fig. 2.3.23 shows that arsenic concentrations in the ambient air have a decreasing trend and with the exception of the marked stations they are below the limit values.

The courses of 14-day average arsenic concentrations (Fig. 2.3.25) show, even more distinctively than in lead, 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, especially in the environs of the presented stations.

Tab. 2.3.14 Stations with the highest values of annual average concentrations of arsenic in the ambient air

Fig. 2.3.23 Annual average concentrations of arsenic in the ambient air in 1992-2001 at selected stations

Fig. 2.3.24 Field of annual average concentration of arsenic in the ambient air in 2001

Fig. 2.3.25 Daily average concentrations of arsenic in the ambient air at selected stations

Nickel

Nickel is the fifth most abundant element of the earth core, though in the earth crust its percentage share is lower. Similarly as in other heavy metals, the sources of nickel are the burning of fossil fuels (heavy fuel oils) and the production of iron.

Table 2.3.15 and Fig. 2.3.26 show that nickel in the air, at least according to the results submitted by the presented HS stations, ranks among the pollutants the concentrations of which are exceeded at many urban stations. Of the total number of 68 stations from which data for 2001 were obtained, the set limit value incl. the margin of tolerance was exceeded at 10 HS stations. Further 11 stations reported the limit value exceedences.

Similarly as in other heavy metals and carbon monoxide, it is necessary to improve the system of nickel measurement quality assurance and inter-comparison of the measured results supplied by the contributing organizations.

Tab. 2.3.15 Stations with the highest values of annual average concentrations of nickel in the ambient air

Fig. 2.3.26 Annual average concentrations of nickel in the ambient air in 1992-2001 at selected stations

Fig. 2.3.27 7/14-day average concentrations of nickel in the ambient air at selected stations in 2001

Mercury

The source of mercury emission is besides the fossil fuels combustion, mainly industrial production (production of chlorine with the use of amalgamation) and metallurgy. The regular mercury monitoring is limited to 8 stations in two localities in the Czech Republic. With the exception of the CHMI station, the data from these stations are accessible in ISKO only for the years 1999, 2000 and 2001. At none of the 8 stations the limit value was exceeded in 2001. The measured concentrations did not even reach the LAT by far.

Tab. 2.3.16 Stations with the highest values of annual average concentrations of mercury in the ambient air

Benzo(a)pyrene

Benzo(a)pyrene is one of the most toxicologically dangerous pollutants. The cause of the presence of this main representative of polyaromatic hydrocarbons (PAHs) in the ambient air is, similarly as in other PAHs 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. Mobile sources are represented mainly by diesel motors.

At present benzo(a)pyren is monitored at 9 stations (8 HS+1 CHMI) of which 6 stations (in Ostrava, Plzeň, Ústí nad Labem, Hradec Králové) report regular exceedences of the set limit value.

The field of annual average benzo(a)pyrene concentrations (Fig. 2.3.29) prepared with the use of combination of emission dispersion models and the measured concentrations illustrate the significant contribution of this component in the delineation of the areas with deteriorated air quality. The areas where the limit values were exceeded represent more than 3 % of the state�s territory with more than 20 % of the population.

Tab. 2.3.17 Stations with the highest values of annual average concentrations of benzo(a)pyrene

Fig. 2.3.28 Annual average concentrations of benzo(a)pyrene in 1992-2001 at selected stations

Fig. 2.3.29 Field of annual average concentration of benzo(a)pyrene in the ambient air in 2001

Fig. 2.3.30 24-hour concentrations at the stations with the highest annual concentrations of benzo(a)pyrene in 2001

Ammonia

The decisive producers of anthropogenic emissions of ammonia are mainly agriculture and some technological processes in chemical industry. It is apparent that ammonia emission in the ambient air are contributed by vehicles (formation of ammonia in catalytic convertors).

Ammonia monitoring is so far limited to 4 stations (1 HS + 3 CHMI). No station reported the exceedence of the limit value in 2001.

Tab. 2.3.18 Stations with the highest values of annual average concentrations of ammonia in the ambient air

2.3.3 Areas with deteriorated air quality with regard to health protection

To delineate zones and agglomerations with deteriorated air quality in line with the new Clean Air Act exceedences of annual average concentrations of SO₂, PM₁₀, NO₂, lead, benzene, cadmium, arsenic, nickel, mercury and ammonia were assessed for each station in accordance with the threshold level and limit values set by the respective legislation. Frequencies of exceedence of daily limit values for PM₁₀ and SO₂ were calculated, as also those of exceedence of hourly limit values of SO₂ and NO₂ and frequencies of exceedence of 8-hour limit values of CO and ozone.

The above mapping procedures were used for the preparation of the maps of spatial distribution of the respective air pollution characteristics (Figs. 2.3.2, 2.3.6. 2.3.7, 2.3.10, 2.3.18, 2.3.21, 2.3.23, 2.3.25 and 2.3.27) presented in the previous subchapters. Areas with the values of air pollution characteristics higher than the respective limit values (areas marked in red, violet to brown) delineate the areas with deteriorated air quality. Table 2.3.19 brings the overview of areas (listed according to regions and districts) in which the limit value for the protection of health was exceeded in 2001 based on the results of mapping air pollution characteristics distribution and indication the exceedence percentage in the respective territory. Table 2.3.20 summarises the areas of exceedences of health protection limit values including the margins of tolerance. The tables show the per cent of exceedence of the respective limit values in the given territory for individual components and air pollution characteristics and summarize the areas in which at least one limit value of the given components was exceeded. The percentages of exceedences presented in the overview in Table 2.3.19 correspond to the percentages of the territories of the given administrative unit in which at least one limit value of the set of air pollution limit values for the protection of health was exceeded.

Table 2.3.21 shows the exceedence of the target limit value for ozone for the protection of health in the regions and districts of the Czech Republic and the share (%) of the respective territory. Ozone is presented separately, as it is evident that the measures aimed at the decrease of ozone concentrations exceeding the target limit value or the long-term air pollution targets, should be taken at the regional or national level.

Tab. 2.3.19 LV exceedences in the regions and districts of the Czech Republic, % of the area of the administrative unit

Tab. 2.3.20 LT+MT exceedences in the regions and districts of the Czech Republic, % of the area of the administrative unit

Tab. 2.3.21 Target ozone limit value exceedences for the protection of health in the regions and districts of the Czech Republic, % of the area of the administrative unit

2.3.4 Air quality with regard to the limit values for the protection of vegetation and ecosystems

Besides the limits for the protection of health the new national legislation introduces, in compliance with EU Directives, also the limits for the protection of vegetation and ecosystems. The survey of the limits is presented in the Table 2.3.22.

Territories in which the Governmental Regulation requires meeting the limit values for the protection of ecosystems and vegetation:

a) national parks and protected areas
b) territories with the altitude > 800 meters
c) other selected forested areas published in the Bulletin of the Ministry of the Environment.

Tab. 2.3.22 Survey of limit values and margins of tolerance for the protection of ecosystems according to the Regulation

Sulphur dioxide

The air pollution situation with regard to the limit values for the protection of ecosystems is shown in the Tables 2.3.23 and 2.3.24 and in Fig. 2.3.31 and 2.3.32. Table 2.3.24 shows that of the total number of 89 stations classified as rural, which supplied data valid for the year 2001, 6 stations reported the exceedence of the limit value for winter average concentration.

Fig. 2.3.31 demonstrates the significant improvement of air quality with regard to sulphur dioxide after 1997 in connection with coming into force of the Act on meeting the set emission limit values by the end of 1998.

The map in Fig. 2.3.32 shows that the exceedences of these limit values occurred only in the limited area of České středohoří.

Tab. 2.3.23 Stations with the highest values of annual average concentrations at rural stations, SO₂

Tab. 2.3.24 Stations with the highest values of winter averages of SO₂ concentrations at rural stations

Fig. 2.3.31 Winter average concentrations of SO₂ in 1992-2001 at selected stations

Fig. 2.3.32 Field of average concentration of SO₂ in the winter period 2000/2001

Nitrogen oxides

Table 2.3.25 and Figs. 2.3.33 and 2.3.34 show the situation of ambient air pollution caused by NO_x with regard to vegetation protection. Of the total number of 99 stations classified as rural, which supplied the data valid for the year 2001, 5 stations reported the exceedence of the limit value for vegetation protection (30 μg.m^-3). As it is evident from the map in Fig. 2.3.34, less than 3 % of the country�s territory recorded the exceedence of the respective NO_x limit values for the protection of ecosystems and vegetation, and namely in northern Bohemia and Central Bohemian Region.

Tab. 2.3.25 Stations with the highest values of annual average concentrations at rural stations, NO_x

Fig. 2.3.33 Annual average concentrations of NO_x in 1992-2001 at selected stations

Fig. 2.3.34 Field of annual average concentration of NO_x in 2001

Ground-level ozone

For the assessment of vegetation protection the national legislation uses, in compliance with the respective EU Directive, the exposure index AOT40. The survey of stations with the highest values of AOT40 is given in Tab. 2.3.26.

The spatial distribution of ozone AOT40 in 2001 is shown in the map in Fig. 2.3.36. It is evident that in more than 43 % of the country�s territory, i.e. in more than 80 % of the territory in which, in compliance with the Regulation the limit value for vegetation must not be exceeded, the AOT40 was exceeded in 2001.

Tab. 2.3.26 Stations with the highest AOT40 values of ozone at rural stations

Fig. 2.3.35 AOT40 values of ozone in 1992-2001 at selected stations

Fig. 2.3.36 Field of AOT40 value of ozone in 2001

2.3.5 Areas with deteriorated air quality with regard to vegetation and ecosystem protection

Based on the mapping of air pollution characteristics distribution for the year 2001 with regard to vegetation protection (Figs. 2.3.32, 2.3.34) the distribution of limit values exceedences is shown for annual average concentrations of NO_x and winter average SO₂ concentrations for the protection of ecosystems and vegetation. Fig. 2.3.36 shows the distribution of the field of AOT40 values for ozone in 2001.

The assessment of the respective limit values exceedences is carried out for the territory defined for the protection of ecosystems and vegetation in accordance with the Regulation of the Government of the Czech Republic.

Table 2.3.27 shows the shares of exceedence of the limit values for the protection of vegetation and ecosystem protection for individual limit values for NO_x, SO₂ and ozone AOT40 for the territory defined by the new legislation. It is evident that in more than 85 % of the territory defined as protected areas the air pollution target for ozone AOT40 is exceeded, mainly due to exceeding ozone concentrations.

Tab. 2.3.27 Shares of the territories for ecosystem and vegetation protection with the LV exceedence, % of the territory of the protected area

2.3.6 Conclusions

The adopted environmental legislation transposing the new EU directives on ambient air will undoubtedly become an important stimulus for further necessary improvement of ambient air quality in the Czech Republic. The air quality assessment procedures which will be implemented within the transposition of the new EU directives represent undoubtedly the compact and elaborate, though rather complicated and not always consistent, system of assessment which should enable to carry out comparable air quality assessment on all-European scale. The limit and threshold values set by the EU directives are deduced thoroughly from the updated recommendations of the World Health Organization, including the limit values for the protection of ecosystems and vegetation. The main consequence of the EU ambient air quality directives transposition is to implement the principle to maintain the state of air quality in those areas where it is good, and to take measures in the form of action plans for the areas with deteriorated ambient air quality.

The carried out assessment for the year 2001 have taken into account the results of the research project VaV740/2/00, covering the years 1998–2000. The following problems were indicated with regard to meeting the deadlines set by the new legislation on the protection of ambient air.

The exceedence of limit values for the suspended particles is a major problem in most European cities. The occurrence of suspended particles in ambient air is a rather complicated phenomenon and their actual concentration expressed in mass number is represented only partially by local emission of primary particles, especially by transport emission. Further contribution to the actual concentration is represented by reemission, and the remaining part by secondary inorganic and organic particles created by chemical transformation of gaseous components both of anthropogenic origin (SO₂, NO_x and non-methane volatile organic compounds), and by emission from the natural environment. Thus the problem of exceeded concentrations of suspended particles in European cities will have to be solved both within all-European cooperation, and at local or regional levels, mainly through measures aimed at local heating and by the reduction of traffic emission, including better street cleaning.

Relatively high contribution of secondary particles show that significant decrease of PM₁₀ concentrations will be possible by further decreasing of emission of the components causing the creation of the fraction of secondary particles in atmospheric aerosol. This demands mainly the decreasing of nitrogen oxides and VOC emissions in compliance with the requirement to meet the national emission ceilings, but in such a way that by the deadlines set by the Clean Air Act the air pollution limit values are met, particularly for PM₁₀. Further decrease of emissions, mainly nitrogen oxides emissions but also of VOC emissions on a large scale, is the only way of possible decrease of the load caused by exceeding concentrations of ground-level ozone.