This chapter of the Yearbook presents regionalised evaluation of air pollution caused by sulphur dioxide, nitrogen oxides, suspended particulate matter (SPM), ozone, carbon monoxide and heavy metals in suspended particulate matter, based on the readings of measuring sites in the Czech Republic. In the end of 1995 (October–December) a new sampling method for suspended particulate matter was introduced and instead of the suspended particulate matter samples without distinction of particulate size only its fraction PM₁₀, important due to its possible health effects, has been measured within the AIM network since.

The first part is devoted to networks of air quality monitoring stations in the Czech Republic. Summary tables of the numbers of stations are presented, broken down by areas, organisations, as well as the type of the pollutant monitored and the measurement type; in addition, a table of annual data set completeness from the station networks is provided. The first part also offers maps that indicate the location of station networks operated by organisations which contribute to the ISKO air pollution database.

The second part deals with the processing of the measured values of pollutant concentrations into maps, graphs and tables that illustrate air pollution in the affected areas of the Czech Republic in 2000. The section that follows deals with the entire Czech Republic and contains maps and tables that provide a concise view of air quality in 2000 summarily for the entire country, and development of air pollution over time.

Besides air quality evaluation based on the monitoring of principal pollutants, also presented are: the evaluation based on regular monitoring of CO and O₃, the evaluation of air pollution caused by heavy metals in SPM, the results of the measurements of aromatic hydrocarbons in ambient air and the evaluation of air pollution caused by persistent organic pollutants.

The concluding part is concerned with the evaluation of meteorological conditions in 2000 in relation to air quality.

The evaluation of the status of the ambient air pollution is based on air pollution limit values as specified in the Decree of the Federal Committee for the Environment of 1 October 1991, attached to Act No. 309/1991 on Air Quality Protection against Pollutants (Clean Air Act), in its full reading in Act No. 211/1994. The annual evaluation of air pollution presented in this Yearbook pursues primarily the relationship between the air pollution levels determined vs. the annual air pollution limit IH_r and the daily air pollution limit IH_d, the values of which are given in the following tab. 2.1. (This Table has been copied over from the above Decree, with some formal modifications.)

Tab. 2-1 Limit values for the Czech Republic

* Calculated as the arithmetic sum of average daily concentrations of the two components.

 ** i.e. the 95th percentiles of daily concentrations must not exceed IH_d and the 95th percentiles of the half-hour concentrations must not exceed IH_k.

 IH_r - average annual pollutant concentration. Average concentration is understood to be the mean value of concentration, determined at a given site over a time period of one year as the arithmetic mean of average 24-hour concentrations.

 IH_d - average daily pollutant concentration. Average concentration is understood to be the mean value of concentration, determined at a given site over a timeperiod of 24 hours. Average daily concentration is also understood to be the mean value of at least twelve evenly distributed measurements of average half-hour concentrations over a time period of 24 hours (arithmetic mean).

IH_8h - average eight-hour pollutant concentration.Average eight-hour concentration is understood to be the mean value of concentration, as determined at a given site over a time period of eight hours.

 IH_k - average half-hour pollutant concentration.Average half-hour concentration is understood to be the mean value of concentration as determined at a given site over a time period of 30 minutes.

Tab. 2-2 Prepared limit values for health protection*

* The prepared limit values for the protection of health pursuant to the draft Decree of the Ministry of the Environment of the Czech Republic setting the air pollution limit values, conditions and requirements for air quality assessment, evaluation and management and implementation of air protection regulation measures, and setting the accessible level of odor nuisance and the way of its detection and the volume of and access to information on air quality.

¹⁾ The margin of tolerance is the per cent of air pollution limit or a part of its absolute value, by which the limit value may be exceeded. This value is reduced regularly in subsequent years until it reaches zero value.

Currently, a new Clean Air Act is under preparation along with its implementing regulations. New legislation reflecting fully the requirements of the European Union will come into force in 2002. The following tables show the limit values and margins of tolerance set by the newly prepared Decree of the Ministry of the Environment of the Czech Republic on air pollution limit values. Some of these values (especially for PM₁₀) were used for the assessment of pollutants in the ambient air for the year 2000.

Tab. 2-3 Prepared limit values for the protection of vegetation and ecosystems*

* The prepared limit values for the protection of vegetation and ecosystems pursuant to the draft Decree of the Ministry of the Environment of the Czech Republic setting the air pollution limit values, conditions and requirements for air quality assessment, evaluation and management and implementation of air protection regulation measures, and setting the accessible level of odor nuisance and the way of its detection and the volume of and access to information on air quality.

¹⁾ The margin of tolerance is the per cent of air pollution limit or a part of its absolute value, by which the limit value may be exceeded. This value is reduced regularly in subsequent years until it reaches zero value.

²⁾ AOT40 is the sum of differences between hourly concentrations higher than the threshold concentration 80 μg.m^-3 (40 ppb) and the value 80 μg.m^-3, in the period from 8 a.m. to 8 p.m. CET.