Czech Hydrometeorological Institute - Air Quality Protection Division

II.4.4 Conclusions

The carried out assessment for the year 2005 has taken into account the requirements of the Government Order No. 350/2002, as amended. The following problems were indicated with regard to meeting the deadlines set by the national legislation on the protection of ambient air.

  • In 2003–2005 84 % of the population (99 % of the territory of the Czech Republic) were exposed to ground-level ozone concentrations exceeding the target air pollution limit values for the protection of human health.
  • Air pollution caused by suspended particles (PM10 fraction) continues to exceed the limit values much more significantly than in 2004. Air pollution limit value for suspended particles came into force on 1.1.2005, already with zero margin of tolerance. The air pollution limit values for 24-hour PM10 concentrations were exceeded in all regions in 2005. The increased total level of air pollution is illustrated by the fact that the increase of PM10 concentrations in 2005 was recorded also at rural background stations. The air pollution limit value for 24-hour concentration was exceeded in 35 % of the territory. The limit value for annual average concentration was exceeded in 1.5 territory of the Czech Republic. In the areas where the PM10 concentration exceeded the air pollution limit values, live more than 65.6 % of the population. 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 PM2.5 fraction of suspended particles started to be monitored in the Czech Republic. The prevailing source of PM2.5 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 PM2.5 measurements were carried out, the proposed annual air pollution limit value was exceeded at 12 localities, further 6 localities would be closely below the limit value. The highest annual average concentrations of PM2.5 were recorded, similarly as in case of PM10, in the localities in the Ostrava-Karviná area.
  • The target air pollution limit value for benzo(a)pyrene is exceeded in Ostrava, Karviná, Prague, Ústí nad Labem and Hradec Králové in the long term. In 2005, due to the extended measurements, exceedences were confirmed in a number of other cities as well. The target air pollution limit value was exceeded approximately in 5.2 % of the territory of the Czech Republic with 35.5 % of the population. Similarly as in the case of PM10, the situation is much worse than in 2004 when 2.57 % of the territory of the Czech Republic with 23 % of the population were exposed to the above-the-limit concentrations.
  • The increasing traffic loads result in exceedences of the air pollution limit values increased by the margin of tolerance for NO2 in the localities exposed to traffic, and namely at 5 stations in the Capital City of Prague and in one station in Děčín.
  • The measurements for the year 2005 indicate that benzene limit value is exceeded in Ostrava again, mainly due to emissions from coking plants.
  • The target air pollution limit value for annual average cadmium concentration was markedly exceeded (approx. 3x) in the locality Tanvald. The locality Tanvald recorded also the exceedence of the target air pollution limit value for arsenic. This station is characterized by long-term high concentrations.
  • In 2005 the air pollution limit values for the protection of ecosystems and vegetation are exceeded in large territory due to the increase of target air pollution limit values of AOT 40 for ozone. This exceedence was recorded on 72.4 % of the area defined for the protection of ecosystems and vegetation by the Government Order.
  • The air pollution limit values of SO2 and NOx for the protection of vegetation and ecosystems were exceeded in 2005 only in 0.02 % of the territory defined for the protection of ecosystems and vegetation by the Government Order, and mainly in Ústí nad Labem, Karlovy Vary and Central Bohemian Regions.
  • 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 exceedence of air pollution 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.

The exceedence 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, NOx 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, but in such a way that by the deadlines set by the Clean Air Act the air pollution limit values are met for PM10. 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.