II.4.4 Conclusions

The carried out assessment for the year 2010 has taken into account the requirements of the Government Order No. 597/2006 Coll., as amended. The following problems were indicated with regard to meeting the deadlines of limit values (target values) set by the national legislation on the protection of ambient air:

• The spatial maps of air pollution characteristics for the year 2011 show the following: the limit value for annual average PM₁₀ concentration was exceeded in 0.7 % of the territory of the Czech Republic in 2011, for 24-hour PM₁₀ concentration in 21.8 % of the territory, for annual average NO₂ concentration in 0.03 % of the territory, and for the annual average benzene concentration in 0.009 % of the territory. Air pollution limit value for at least one pollutant was exceeded in 21.8 % of the territory of the Czech Republic. The target value for arsenic annual average concentration was exceeded in 0.005 % of the territory of the Czech Republic, for the annual average concentrations of nickel in 0.005 % of the territory of the Czech Republic and for benzo(a)pyrene in 16.8 % of the territory. The target value for at least one pollutant was exceeded in 16.9 % of the territory of the Czech Republic (ground-level ozone not included).
   

• The levels of air pollution caused by PM₁₀ particles continue to exceed the set limit values. In 2011 there was recorded only slight decrease of the 36^th highest PM₁₀ concentration (in average for all types of localities). Nevertheless, in comparison with the year 2010 the increase of concentrations at urban traffic stations was recorded. The average concentration at most rural station decreased below the level of the daily limit value, the concentrations in other types of localities remain above the limit value in most cases. The exceedance of the 24-hour limit value for PM₁₀ at least in one locality was recorded in 2011 in all zones and agglomerations. The limit value for 24-hour PM₁₀ concentration was exceeded in 2011 in all localities in the agglomeration Moravian-Silesian Region and in more than half or most of the localities in the zones Ústí nad Labem, Central Bohemian, Olomouc and Zlín regions and in the agglomerations Prague and Brno. The limit value for the 24-hour average concentration was exceeded in 2011 in 21.8 % of the territory (in 2010 in 21.21 %, in 2009 in 4.4 % of the territory). The limit value for annual average concentration was exceeded in 2011 in 0.7 % of the territory of the Czech Republic (in 2010 in 1.85 % of the territory, in 2009 in 0.54 % of the territory). In the territory where the PM₁₀ concentrations exceeded the limit values in 2011, live approximately 50.8 % of the population (in 2010 it was 48 % of the population, in 2009 18 % of the population). The most serious air pollution situation caused by suspended particles remains in the agglomeration Moravian-Silesian Region (Ostrava-Karviná area). This is caused by the fact that in this area, in addition to transport and local sources (household heating), which are the main emission sources of suspended particles also in other regions, significant contribution is made by further emission sources, and mainly metallurgy and fuel processing. Air pollution loads of this area are influenced also by regional transfer from the sources in Poland (heavily industrialized Katowice area).
   

• In 2004 the concentrations of the fine PM_2.5 fraction started to be measured in the Czech Republic. The prevailing source of PM_2.5 fraction emissions are combustion processes, producing secondary particles originating as a result of chemical reactions between the gaseous compounds and condensation of hot gases and vapour. The measurement results for the year 2011 show significant air pollution in the territory of the Moravian-Silesian Region (Ostrava and Karviná area). Out of 49 localities, where the PM_2.5 measurements were carried out in 2011, the target value for annual concentration was exceeded in 13 localities, and namely in 8 localities in the Ostrava-Karviná area, in 3 localities in the Brno agglomeration, one locality in the zone Olomouc Region and one locality in the zone Plzeň Region. For the first time also the map of the field of average annual concentration of PM_2.5 suspended particles was created for the 2011 assessment. The estimated part of the territory of the Czech Republic with the exceedances of the limit value is 2.6 %. The share of inhabitants exposed to the above-the-limit PM_2.5 concentrations is estimated to 13.5 %.
   

• The concentration of the ground-level ozone – the �summer� pollutant of photochemical origin – is influenced by the character of the weather in the warm half of the year. There was no marked change of the situation as against the previous period 2008–2010. The comparison shows that in 2009–2011, in general, the number of localities with the exceedance of the target value 120 μg.m^-3 slightly decreased. The long-term target was exceeded in all localities (except one traffic locality) in 2011. About 10.1 % of population were in average exposed to the concentrations of the ground-level ozone exceeding the target values for the protection of human health in the assessed period 2009–2011.
   

• A lot of towns and villages were assessed, similarly as in 2010, as the areas with exceeded target value for benzo(a)pyrene, and namely 16.8 % of the territory of the Czech Republic with approximately 60.2 % of the population. In comparison with the year 2010 there was not recorded a significant change of the situation concerning the share of the territory and population of the Czech Republic exposed to the above-the-limit benzo(a)pyrene concentrations. The comparison with the year 2010 shows that in 2010 the respective numbers were 14.47 % of the territory and 65 % of inhabitants.
   

• The current exceedances of the 24-hour limit values for the PM₁₀ suspended particles and target values for benzo(a)pyrene and PM_2.5 particles can be regarded as alarming, especially in connection with their serious impacts on human health. It is supposed that both the increased and exceeding concentrations of benzo(a)pyrene may occur also in the towns and villages where there is no air pollution measurement, mainly due to emissions from local sources (household heating) and traffic.
   

• The increasing traffic loads result in exceedances of the limit values for NO₂ in the localities exposed to traffic, and namely at 8 stations in Prague, Brno and Ostrava. The limit value exceedances can be expected also in other similarly traffic loaded sites, where there are no measurements applied. In 2011, as compared with 2010, NO₂ concentrations decreased in most localities. Approximately 0.2 % of the population were exposed to the above-the-limit concentrations in 2011.
   

• The measurements for the year 2011 indicate that benzene limit value is exceeded in Ostrava repeatedly, mainly due to emissions from coking plants. Approximately 0.01 % of the population were exposed to the above-the-limit concentrations in 2011.
   

• The limit value for the protection of human health for 24-hour and hourly SO₂ concentrations was not exceeded in 2011 at any monitoring station in the Czech Republic. Based on the dispersion model, one of the prerequisites for the creation of spatial maps of air pollution characteristic, the SO₂ limit values for 24-hour concentrations and for ecosystems and vegetation were exceeded in a very small area of the zone Ústí nad Labem Region.
   

• The target value for annual average concentrations of arsenic was exceeded in two localities in the Kladno area and in Prague (Stehelčeves, Prague 5-Řeporyje) in 2011. About 0.002 % of the population of the Czech Republic inhabiting 0.005 % of the territory of the Czech Republic were exposed to the above-the-limit concentrations in 2011.
   

• The target value of the annual average concentrations of nickel was exceeded in 2011 in the locality Příbram I-nemocnice. The exceedance was caused by high concentrations in the first third of the year connected probably with demolition activity near the measuring station.
   

• The target values for the annual average concentration of cadmium and the limit values for annual average concentration of lead and SO₂ and for the maximum 8-hour concentration of CO were not exceeded in 2011 at any monitoring station.
   

• The target value for ozone AOT40 for the protection of vegetation was exceeded in the assessed five-year period 2007–2011 in lower number of localities (8 out of 37) as compared with the previous assessed period 2006–2010 (20 out of 37). This decrease was significantly apparent as concerns the area of the territory of the Czech Republic with the exceedances. The long-term target was exceeded in 2011 in all rural localities except one.
   

• The limit values for the annual average concentration of NO_x and SO₂ and the limit value for the winter average of SO₂ for the protection of vegetation and ecosystems were not exceeded in 2011 at any rural locality where the measurement is carried out.
   

• In agglomerations, the problem of the increased pollutants� concentrations is particularly serious and a great number of people are affected due to the high population density. The exceedance of limit values in the Prague agglomeration is connected mainly with the significant traffic load and also with the fact that the communications with heaviest traffic run directly through the city centre. The results of the measured concentrations of PM₁₀, NO₂ and benzo(a)pyrene still suggest to find the solution of this absolutely unsatisfactory traffic situation in Prague, where the above-the-limit concentrations impact considerable share of the population. Similar situation can be found in the localities with traffic loads in the Brno agglomeration. In the agglomeration Moravian-Silesian Region significant contribution to air pollution, in addition to transport, is made by metallurgy and fuel processing industry. With regard to high population density in the agglomerations, the significant source of air pollution is also local heating, mainly in the built-up areas with family houses. In the agglomeration Moravian-Silesian Region local heating has its influence at ambient air quality also in small settlements.

The overview of the most polluted localities of the Czech Republic with exceedances of PM₁₀ fraction annual limit value (40 μg.m^-3) includes mainly the areas of the Moravian-Silesian Region. Similar situation is in the exceedance of the target value for annual average concentrations of fine particles of PM_2.5 fraction. The annual average concentrations of benzo(a)pyrene continuously exceed the annual target value 1 ng.m^-3 in a number of large settlements throughout the whole Czech Republic. The assumption concluded at in the recent years that this limit value is exceeded also in smaller settlements was confirmed in 2011 thanks to the measurement in three small settlements. In many localities (mainly in the Moravian-Silesian Region and in Kladno) there were recorded even manifold exceedances of the limit values in 2011.

The exceedance of the 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, NH₃ and VOC), and by emission from the natural environment. Thus the problem of high 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 shows that significant decrease of PM₁₀ concentrations will be possible by further decreasing of emission of the components causing the creation of secondary particles (NOx, SO₂, NH₃ and VOC). Further decrease of emissions, mainly NOx emissions but also VOC emissions on a large scale, is the only possible way how to decrease the loads caused by exceeding ground-level ozone concentrations.

The assessment of the ambient air pollution is based on the measurement which is focused, pursuant to the legislative requirements, mainly in large cities. The expert estimates and the results of the published works show, however, that it is highly probable that both the increased and above-the-limit concentrations of a number of pollutants occur also in a number of small towns and villages where there is no air pollution monitoring carried out and where lives a relatively large share of population of the Czech Republic. The substances concerned are mainly suspended particles and polycyclic aromatic hydrocarbons. The essential role in air pollution is played by geomorphological conditions, meteorological conditions, traffic loads and the type of heating, especially in the appliances not suitable for the given type of fuel. Due to burning wood and coal there occur increased emissions of particles, PAH and heavy metals. Moreover, by burning refuse in local furnaces dangerous dioxins are emitted in the ambient air.