II.4 Air quality assessment

The extent of air pollution is objectively determined by monitoring the concentrations of ambient air pollutants (air quality monitoring) in the ground layer of atmosphere within the network of measuring stations. Within air quality assessment there are compared mainly the recorded levels of air pollution concentrations with the respective limit values or with admissible exceedance frequencies of these limits, i.e. air pollution levels which should not be exceeded after the date set by the valid air quality legislation.

The Yearbook presents air quality assessment in the year 2012 with regard to the requirements of the Czech legislation on air quality protection. Pursuant to the Act No. 201/2012 Coll. on Clean Air Protection the assessment is aimed at defining the areas with exceedances of the limit values, both for the protection of health and the protection of ecosystems and vegetation.

Air quality assessment pursuant to the valid legislation reassumes the results and methods developed within the two research projects solved by CHMI, and namely VaV/740/2/00 �Evaluation of the Czech Republic Readiness to Meet Air Quality Requirements of EU Directives and the LRTAP Convention� [12], and VaV/740/3/02 �Integrated air quality assessment and management with regard to the daughter directives on heavy metals, PAH, PM₁₀ and benzene� [19].

The EU air quality directives on which the Czech legislation is based require that the member states should divide their territories into zones and agglomerations while the zones and agglomerations are understood as basic units for air quality management. The directives specify namely the requirements for the assessment – the classification of the agglomerations and the zones with regard to air quality. The Act No. 201/2012 Coll.), covers this issue in par. 5 dealing with the assessment and evaluation of the level of air pollution. Article 1 of par. 5 states that the Ministry ensures, in order to evaluate the level of air pollution, the assessment of the level of air pollution and the comparison of the result level of air pollution with the limit values.

The zone is a part of the territory delimited by the Ministry of Environment for the monitoring and management of air quality, and the agglomeration is a residential area where the population concentration is at least 250,000 inhabitants. Act No. 201/2012 on Clean Air Protection defines three agglomerations were defined; the Capital City of Prague and the city of Brno agglomerations represent the areas where ambient air pollution is connected mainly with traffic loads and high density of population, in the agglomeration Ostrava/Karviná/Fýdek-Místek air pollution is influenced, besides population density, also by high concentration of industrial plants. Due to the delineation of agglomerations air quality assessment in these areas will be determined mainly on the basis of regular measurements of good quality. Other areas of the Czech Republic, delineated for ambient air quality assessment, correspond to the NUTS2 units (excluding CZ06 and CZ08) and they are defined as zones. In total seven zones were defined.

The Yearbook deals separately in great detail with individual areas where ambient air quality is significantly influenced by factors such as increased concentration of industry and traffic, by increasing intensity of traffic or by the combination of these factors, and at the same time by higher density of population in these areas. Similarly as in the previous yearbooks more detailed assessment of ambient air quality is devoted to the agglomerations, the Ústí nad Labem Region, the Hradec Králové Region and the Pardubice Region.

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 2008/50/EC. Where the objectives for ambient air quality laid down in this Directive are not met, Member States should take action in order to comply with the limit values and long-term objectives.

If a zone or agglomeration exceeds the limit value set in points 1 to 3 of Annex No. 1 of the Act 201/2012 Coll., or if the limit value set in point 1 of Annex No. 1 is exceeded more than the set maximum number of exceedances, the Ministry develops, in cooperation with the respective regional or local authority, the programme aimed at the improvement of air quality for the given zone or agglomeration within 18 months following the end of the calendar year in which the limit value was exceeded. During the programme development the Ministry adopts the respective measures in order the limit value is met as soon as possible.

The term �hot spot� is used in the assessment, generally for localities with high level of ambient air pollution. In our assessment, however, this term refers to the stations oriented exclusively to traffic and to the resulting increased air pollution loads. The monitoring stations classified as hot spots are operated by CHMI in the localities with heavy traffic loads in Prague, Brno, Ostrava and Ústí nad Labem. These localities meet the criteria for the location of traffic-oriented samplers pursuant to the Decree No. 330/2012 Coll., on the method of assessment and evaluation of ambient air pollution level, on the extent of informing the public on the level of ambient air pollution and during smog situations.

The air quality assessment is documented by the tables showing the localities with the highest values of air pollution characteristics set by the Czech legislation. The shades of the background in the tables indicate:

All tables for individual pollutants present at least 10 stations with the highest values of the respective air pollution characteristic in the given year. The maps depict clearly the development of the respective characteristics in the period 2002–2012. The 2012 exceedance of the limit value is highlighted with red names of the stations in the maps.

Further, maps depicting the spatial distribution of air pollution characteristic are presented. These maps show also the measuring stations marked with different symbols and colours according to their type and category of the level of the respective air pollution characteristic measured at the presented station. The intervals of the classes in the legend are based on the lower and upper assessment thresholds and on the limit value for individual substances. The exceedance of the limit value is marked with red colour.

For the stations and air pollution characteristics, where the number of exceedances of the limit value was higher than it is allowed, the courses of 24-hour or hourly concentrations in 2012 are presented for the indication of the period of the year during which the limit values were exceeded.

The courses of air pollution caused by individual pollutants at selected stations during the year 2012 are documented by the graphs.

The Yearbook includes the graphs showing the trends of the characteristics of selected pollutants in agglomerations and in the whole territory of the Czech Republic starting from the year 1996. The values depicted in the graphs are calculated as total average from average concentrations only of those monitoring stations in the given territory which measured the monitored pollutant for the whole evaluated period.