II.4.4 Conclusions

 
The carried out assessment for the year 2006 has taken into account the requirements of the Government Order No. 597/2006. The following problems were indicated with regard to meeting the deadlines set by the national legislation on the protection of ambient air.

• In 2004–2006 78 % of the population (88 % of the territory of the Czech Republic) were exposed to ground-level ozone concentrations exceeding the target values for the protection of human health.
• Air pollution caused by suspended particles (PM₁₀ fraction) continues to exceed the limit values, similarly as in 2005. The limit values for 24-hour PM₁₀ concentrations were exceeded in all zones and agglomerations in the Czech Republic in 2006. The limit value for the 24-hour average concentration was exceeded in 28.5 % of the territory (in 2005 in 35 % of the territory). The limit value for annual average concentration was exceeded in 2.3 % of the territory of the Czech Republic (in 2005 in 1.5 % of the territory). Certain reduction of the area with 24-hour limit value exceedances in 2006 resulted from the decrease of air pollution caused by PM₁₀, especially in the area along the Elbe River and in the Liberec Region. In the areas where the PM₁₀ concentrations exceeded the limit values in 2006, live more than 62 % of the population (in 2005 almost 66 %). The most serious air pollution situation caused by suspended particles is in the Moravian-Silesian Region (Ostrava-Karviná area). This is caused by the fact that in this area, in addition to transport and local sources, 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 2005, pursuant to EU recommendations ensuing from 1999/30/EC Directive, the monitoring of the concentration of the fine PM_2.5 fraction of suspended particles started to be monitored in the Czech Republic. The prevailing source of PM_2.5 fraction 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 show significant air pollution in our territory. Of 25 localities, where the PM_2.5 measurements were carried out in 2006, the proposed annual limit value was exceeded at 14 localities. The highest annual average concentrations of PM_2.5 were recorded, similarly as in case of PM₁₀, in the localities in the Ostrava-Karviná area.
• The target value for benzo(a)pyrene is exceeded in Ostrava, Karviná, Plzeň, Teplice, Prague, Ústí nad Labem and Hradec Králové in the long term. In 2006, due to the new, more precise mapping methods, exceedances were confirmed in a number of further cities. The target value was exceeded approximately in 9 % of the territory of the Czech Republic with the whole 69 % of the population of the Czech Republic.
• The current exceedances of the limit values for the PM₁₀ suspended particles and benzo(a)pyrene and the proposed limit values for fine PM_2.5 particles, can be regarded as alarming, especially in connection with their serious impacts on human health.
• The increasing traffic loads result in exceedances of the limit values increased by the margin of tolerance for NO₂ in the localities exposed to traffic, and namely at 3 stations in the Capital City of Prague and at one station in Brno and one station in Olomouc.
• The measurements for the year 2006 indicate that benzene limit value is exceeded in Ostrava again, mainly due to emissions from coking plants.
• The target value for annual average concentrations of arsenic was exceeded in Ostrava and in Kladno (Švermov). About 2 % of the population of the Czech Republic were exposed to the above-the-limit concentrations.
• The target values for the annual average concentrations of cadmium, nickel, lead and CO were not exceeded in 2006. The station Tanvald, which recorded regular significant exceedances of the target value for cadmium every year, could not be included in the processing as, unfortunately, it measured only for 4 months in 2006, and therefore there were not sufficient valid data for the calculation of the annual average. Nevertheless the data measured for the 4 months at this station show that the target value would be very likely exceeded again at this station.
• The target value for ozone AOT40 for the protection of vegetation was exceeded almost throughout the Czech Republic in 2006.
• The limit values of SO₂ and NO_x for the protection of vegetation and ecosystems were not exceeded in 2006 at any rural monitoring station.
• In agglomerations, the problem of the increased pollutants� concentrations is particularly serious and a great number of people are affected due the high population density. The exceedance of limit values in the Capital City of Prague is connected mainly with the significant traffic load and also with the fact that the communication with heaviest traffic runs directly through the city centre. The results of the measured concentrations of PM₁₀, NO₂ and benzo(a)pyrene suggest to find the solution of this absolutely unsatisfactory traffic situation in the agglomeration, where the above-the-limit concentrations impact considerable share of the population. Similar situation can be found in the localities with traffic loads in Brno. In the Moravian-Silesian Region significant contribution to air pollution, in addition to transport, is made by metallurgy and fuel processing industry, and mainly in Ostrava which is the most polluted locality in the Czech Republic.

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 (i.e. the whirling of already emitted particles for instance from the road surface or from building sites), 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 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 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. Further decrease of emissions, mainly nitrogen oxides emissions but also of 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 mainly in large agglomerations pursuant to the legislative requirements. 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 small towns and villages where there are no measurements carried out and where lives a relatively large share of population of the Czech Republic. The substances concerned are mainly as follows: suspended particles, polycyclic aromatic hydrocarbons and heavy metals. The essential role in air pollution is played by geomorphological conditions, traffic loads and the type of heating. Due to burning wood and coal there occur increased emissions of particles, polycyclic aromatic hydrocarbons and heavy metals. Moreover, by burning refuse in local fire places dangerous dioxins are emitted in the ambient air.