Level Index range Air quality
     1A      ≥ 0.00 and < 0.34 very good to good
     1B      ≥ 0.34 and < 0.67
     2A      ≥ 0.67 and < 1.00 acceptable
     2B      ≥ 1.00 and < 1.50
     3A      ≥ 1.50 and < 2.00 aggravated to bad
     3B      ≥ 2.00
Component is not measured
Incomplete data

The conditions for the determination of air pollution index

The calculation of air quality index is based on the assessment of 1-hour concentration of sulphur dioxide (SO2), nitrogen dioxide (NO2), suspended particles (PM10), 8-hour running concentrations of carbon monoxide (CO) and 1-hour ground - level ozone concentrations (O3) in the summer period (1. 4. - 30. 9.). The calculation considers the possible impact of air pollution on the health of population. The calculation for PM10 uses 1-hour average concentrations because they better reflect the current situation (the limits for 1-hour concentrations were derived on the basis of statistical analysis of 24-hour and 1-hour concentrations).

The 1-hour ozone concentrations (O3) are given in the winter period (1. 10. - 31. 3.) as well, although they are not included in the calculation of air quality index. For information purposes, the last column presents the 24-hour running average concentrations of PM10, which are not included in the calculation of air quality index.

  1. Data for the calculation of air quality index are based on current measurements and they are not verified.
  2. Air Quality Index is shown for each quantity in a given locality separately and as an overall index for the locality in column Air Quality is presented the highest of them. Conditions for display is the measurement of PM10 on the site.
  3. Air quality index is imaged in case the 1-hour data are available at least for NO2, O3 and PM10 in the summer period (1.4. - 30.9.) or at least for NO2 and PM10 in the winter period (1.10. - 31.3.), if they are subject of standard measurements in the locality.
  4. The term “incomplete data” may indicate that the instruments at the station were under calibration during the respective hour.
  5. The air quality index is based on data measured strictly pursuant to the current national legislation (Act No. 201/2012 Coll. on air protection, as amended, and Decree No. 330/2012 Coll. on the method of assessment and evaluation of ambient air pollution levels and on the extent of informing the public about levels of ambient air pollution and during smog situations) and pursuant to the requirements of the European Union.