Air and precipitation quality


The results of long-term measurements show that almost all pollutants measured have a decreasing trend (their concentration is declining in the long run). This decline is generally a result of restructuring the national economy, the modernization of pollutant producing facilities (especially in the sector of industry), and termination or limitation of some production operations. The most significant decrease of emissions in the Czech Republic can be noted in the 1990–2001 period. Further gradual decrease of emissions in 2002–2012 can be attributed to the new legislation implementing a range of European directives. In addition to legal measures, a decline in a number of manufacturing sectors due to the economic crisis was reflected in the decrease of emissions. The emission reduction trend continues in the 20132016 period, and other technical measures are in place to reduce emissions in the industry. The Act on protection of the air has also focused on reducing emissions from local heating of households by limiting the production of selected combustion sources between 2014 and 2018 (CHMI, 2016).

Both the local pollution and the long-range transport of polluting substances across borders affect the monitored pollution. The Košetice observatory as a background station in Central Europe is more or less at the average in view of the level of measured pollution.

SO2 concentrations decreased from an average annual value of 14.5 μg·m-3 in 1985 to 2.2 μg·m-3 in 2017. However, the highest annual concentrations of 27.8 μg·m-3 was registered in 1991. The average SO2 concentrations in the Czech Republic were less than 6 μg·m-3 in 2016, the concentration at rural stations slightly exceeded 4 μg·m-3.

NO2 concentrations decrease very slightly, the average annual concentrations fluctuate within the range from 6 μg·m-3 to 12.1 μg·m-3. In 2017, the annual concentration was 6.9 μg·m-3. In 2016, the average concentration of NO2 in the Czech Republic was 18 μg·m-3. In industrial areas in the west of Germany and northern Italy, annual NO2 concentrations exceeding 30 μg·m-3 are measured at many stations.

Concentrations of PM10 aerosol particles decreased from 29.4 μg·m-3 (in 1996) to 16.4 μg·m-3 (in 2017). In spite of the long-term decreasing trend, concentrations in the monitored period increased after 2001. This increase was the result of unfavourable meteorological conditions and it was reflected in the measurements of all stations in the Czech Republic. Average concentrations of PM10 in the Czech Republic were 25 μg·m-3 in 2016, concentrations at rural stations slightly exceeded 20 μg·m-3. Most stations in Europe registered concentrations less than 30 μg·m-3 in 2015, except for stations in Poland, northern Italy and Bulgaria, where concentrations exceeded both the value of 30 μg·m-3 and also the limit level, i.e. 40 μg·m-3 at an annual average.


The Mann-Kendall non-parametric test was used to evaluate air quality and precipitation quality trends. This test was also used as a mandatory method when comparing trends within the EMEP Evaluation Study across Europe. It allows evaluating even incomplete longer data series and does not require a specific data set distribution.

The Z-test characterizes the existence and significance of the trend, positive (negative) values.

Significance of trends in 4 categories of values:

*** if α = 0.001

** if α = 0.01

* if α = 0.5

+ if α = 0.1

Q represents an average annual increase or decrease.

Results are in czech 



Results (only in czech):

Koncentrace SO4 [µg.m-3]  1985–2016.            Koncentrace SO2 [µg.m-3]               Koncentrace CO [µg.m-3]  1996–2017.                 Koncentrace NO2 [µg.m-3]  1994–2017.

Koncentrace SO4 [µg.m-3] 1985–2016.       Koncentrace SO2 [µg.m-3] 1985–2017.      Koncentrace CO [µg.m-3] 1996–2017.        Koncentrace NO2 [µg.m-3] 1994–2017.


Koncentrace PM10 [µg.m-3]  1996–2017.              Koncentrace PM2,5 [µg.m-3]  2012–2016.                 Koncentrace elementárního uhlíku EC [µg.m-3]   2010–2017.                    Koncentrace organického uhlíku OC [µg.m-3]   2010–2017.

Koncentrace PM10 [µg.m-3] 1996–2017.   Koncentrace PM2,5 [µg.m-3] 2012–2016.      Koncentrace elementárního uhlíku EC  a organického uhlíku OC [µg.m-3] 2010–2017. 


Koncentrace CH4 [µg.m-3] 1997–2016.

Koncentrace CH4 [µg.m-3] 1997–2016.

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