The periodically published Tabular Survey is a result of the processing of air quality data that is systematically stored over the calendar year in the air quality database from all significant networks monitoring air pollution in the country. From the table Air pollution monitoring sites based on the owner and location in the administrative region of the Czech Republic - 1999 it is apparent from how many monitoring (active) stations of the overall number of the stations data were stored and processed.

Since 1992, the current information technology was utilized to prepare the Air Quality Information System (ISKO) and the restructured former Imission Information System (IIS) became an integral component, along with other information programs for evaluating air quality.

The Air Quality Information System collects and generally provides access to data gathered within significant air pollution monitoring networks. It thus allows more effective general utilization of this expensive data. The integrated regionalised evaluation of air pollution levels, and analysis of the development over time of the status of air pollution in this country would not be feasible without collecting and archiving systematically at one place all the air pollution data available. The continuous need to make this assessment objective also necessitates simultaneous accessibility of emission, meteorological and climatic data and geographic information on the locations of pollution sources, the extent and location of forest growth, residential areas, roadways and similar information.

Fig. 1 schematically depicts ISKO´s links to data sources and co-operating systems. The scheme outlines the interconnection of air quality monitoring networks and sources of data on emissions with data processing and information layers represented by ISKO, and the linkage to a higher-level layer - cross-sectional information systems. The actual interconnection is carried out through exchange of data on magnetic media, over switched data lines and, in case of data from the AIM network, also over fixed circuits of the CHMI´s private data network.

Computer System

Since 1993, both the Tabular Survey and the Graphic Yearbook have been completely prepared on an innovated computer system. It consists of a computer network around an SUN ENTERPRISE 450 database server with the installed Ingres II multi-user relative database system under the Solaris operating system. The data core of the information system is implemented under RDBMS Ingres with predominant utilization of client-server architecture. The concept of the system is based on distributed processing in the local network at Sun SPARC working stations and personal computers with direct access of processing and analytical programs, such as the ARC/INFO geographical information system on Sun ULTRA, the statistical programs SPSS, Systat, tabular and graphical programs Excel and Harvard Graphics, etc., to the data in the central database on SUN ENTERPRISE 450 with features of uninterrupted and backed-up operation.

The Czech Hydrometeorological Institute has its regional offices in all the former regional capitals, which are mainly concerned with measurements, data collection and initial processing within their respective regions. The offices are connected to the central system in Prague via CHMI´s private data network. This Institute´s organizational structure and current technical facilities, as well as a growing need to ensure that the regional offices and cooperating organizations can manage a matching scope of data processing and utilization for their areas, indicate the need for a gradual transition to some form of a more thoroughly allocated concept of the entire Air Quality Information System.

Air pollution assesment

Assessment of the status of the air pollution is based on air pollution limit values as specified in the Decree of the Federal Committee for the Environment of October 1, 1991, attached to Act No. 309/1991 Coll., the Clean Air Act in wording of Act No. 211/94 Coll. (This Table has been copied over from the above Decree, with some formal modifications).

Limit values for the Czech Republic
Pollutant Expressed as Limit values [µg.m-3]
IHr IHd IH8h IHk General requirement**
Suspended particulate matter SPM 60 150   500 IHd and IHk must not be exceeded in more than 5% of measurements annually.
Sulphur dioxide SO2 60 150   500
Sulphur dioxide and suspended particulate matter SO2 + SPM   250*      
Nitrogen oxides NO2 80 100   200 IHd and IHk must not be exceeded in more than 5% of measurements annually.
Carbon monoxide CO 5000 10 000
Ozone O3  160  
Lead in suspended particulate matter Pb0.5    
Cadmium in suspended particulate matter Cd 0.01    

Legends
*
Calculated as the arithmetic sum of average daily concentrations of the two components
**
i.e. the 95th percentiles of daily concentrations must not exceed IHd and the 95th percentiles of the half-hour concentrations must not exceed IHk
IHr
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
IHd
average daily pollutant concentration. Average concentration is understood to be the mean value of concentration, determined at a given site over a time period 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)
IH8h
 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
IHk
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



In those monitored pollutant concentrations, for which air quality standards have not been set out by the Czech legislation so far, alimit values of adopted or proposed EU directives are used as reference values. Guideline value set out by the World Health Organization (WHO) is used in case where there is no proposal of the respective directive. The above mentioned pollutants are: thoracic fraction of particulate matter PM10, NO2, benzene and arsenic in suspended particulate matter. The respective standards, to which the measured concentrations are related, are given in the following table.

Limit values based on or proposed EU directives
Pollutant Interval for calculation of the arithmetic mean Limit entry [µg.m-3] Limit for year 2005 [µg.m-3] Admissible exceedence
PM10 (*)2
24 hours
75
50
Must not be exceeded in more then 35 measurement annually.
PM10 (*)2
calendar year
48
40
  
NO2 (*)2
calendar year
60
40
  
Benzen3
calendar year
10
5 for year 2010
  
As4
calendar year
0.03
0.03
  

Legends
1 limit values related to the year of the entry into force of the directives
2 limit values of adopted EU directives
3 limit values of proposed EU directives
4 guideline values set out by World Health Organization (WHO) in case where is no proposalof respective directive