Atmosperic deposition is the flow of substances from the atmosphere towards the Earth’s surface (Braniš, Hůnová 2009). This is an important process contributing to self-cleaning of air, however, on the other hand it enables the pollutants’ entering to other components of the environment. Atmospheric deposition is divided into wet deposition and dry deposition. Wet deposition is connected with the occurrence of atmospheric precipitation (vertical deposition: rain, snow, and horizontal deposition: fog, rime), and therefore it has an episodic character. The dry component represents the deposition of gases and particles through different mechanisms and it is a continuous process.

The quantification of total atmospheric deposition is very important for the study of its effects on the environment. There is a significant difference in the quantification of individual components with regard to the level of difficulty of the method and reliability of the obtained results. Wet vertical deposition is relatively easiest to measure (Krupa 2002), while there is no available method for the direct measurement of dry deposition, and thus it is necessary to estimate it with the use of various, usually relatively complicated approaches (Wesely, Hicks 2000; Kumar et al. 2008). Nevertheless, the most difficult measurable component of atmospheric deposition is horizontal deposition (e.g. Krupa 2002; Klemm, Wrzesinsky 2007). It is measured only exceptionally and actual deposition, with regard to this component, is usually significantly underestimated (Bridges et al. 2002; Hůnová et al. 2011).

Atmospheric deposition in Europe has decreased significantly over the recent twenty years, however, in a number of regions it still continues to be a problem (EEA 2011). Chemical composition (precipitation quality) and atmospheric deposition have been monitored in the long term at relatively large number of stations in the Czech Republic. Time trends and changes in spatial distribution of major components of deposition, i.e. sulphur and nitrogen, for the whole period of the carried out measurements were published (Hůnová et al. 2004; 2014).

In 2013 the Air Quality Information System (ISKO/ AQIS) database obtained data on precipitation quality from 42 localities in total (13 ČGS, 14 CHMI, 8 VÚLHM and 6 HBÚ AV ČR. Further, data from 5 German localities) in boundary areas were submitted by LfULG. Most of the CHMI stations measure wet-only samples in weekly interval (monthly interval was switched over to weekly interval in 1996 in line with the EMEP methodology). Further, from 1997 to 2010 the weekly precipitation sampling, “bulk” type (with non-specified content of dustfall), for heavy metals analysis was carried out at these stations. Since 2011 the analyses of heavy metals at CHMI stations have been carried out from wet-only precipitation sampling, “bulk” type sampling was closed down. In the localities of other organizations monthly sampling (or irregular sampling) is used for measuring concentrations in precipitation (“bulk” type) in the open area (or throughfall). The detailed information on individual localities and sampling types is presented in Table IX.4.

Wet deposition charts were compiled for selected ions on the basis of all-round chemical analyses of wet only precipitation samples, specifically for SSO42--S, NO3--N, NH4+-N, H+ (pH), Cl-, F- , Pb2+, Cd2+ and Ni2+.

The above ions were selected to represent deposition fields with regard to their considerable impact on the various spheres of the environment. Wet deposition charts for each of the ions were derived from the field of ion concentrations in precipitation (based on annual mean concentrations weighted by precipitation totals calculated from the data observed), and from the field of annual precipitation totals which was generated on data from 750 precipitation gauging stations, taking into account the altitude’s effect on precipitation amount. When constructing wet deposition fields, results of wet-only samples analysis are preferred to “bulk” samples with dustfall, and weekly samples are preferred to monthly samples. Data from the network stations operated by ČGS, VÚV and VÚLHM based on monthly “bulk” sampling with dustfall (Table IX.4) are modified by empirical coefficients expressing the individual ions’ ratios in “wet-only” and “bulk” samples (values for each of the ions from 0.74 for NH4+ to 1.06 for H+) for the purpose of the development of the wet deposition charts. The fact that in case of H+ cations the ratio is higher than 1, can be explained in the following way: the solid particles contained in the “bulk” type samples react with hydrogen cations, which results in their decreasing concentration (Ranalli et al. 1997).

In addition to wet deposition, also dry deposition charts are presented for sulphur, nitrogen, hydrogen ions, lead and cadmium. The maps of total annual deposition are presented for sulphur, nitrogen and hydrogen ions.

Dry sulphur and nitrogen deposition was calculated using fields of annual mean SO2 and NOx concentrations for the Czech Republic, and the deposition rates for SO2 0.7 cm.s-1/0.35 cm.s-1, and NOx 0.4 cm.s-1/0.1 cm.s-1, for the forested/unforested areas (Dvořáková et al. 1995).

Total deposition charts were produced by adding S and N wet and dry deposition charts. The wet hydrogen ion deposition chart was compiled on the base of pH values measured in precipitation. Dry hydrogen ion deposition reflects SO2 and NOx deposition based on stechiometry, assuming their acid reaction in the environment. The total hydrogen ion deposition chart was developed by summation of wet and dry deposition charts.

The average deposition fluxes of S, N and H are presented in the Table IX.1.

Throughfall sulphur deposition chart was generated for forested areas from the field of sulphur concentrations in throughfall and a verified field of precipitation, which was modified by a percentage of precipitation amounts measured under canopy at each station (64–87 % of precipitation totals in an open area for the year 2013). Throughfall deposition generally includes wet vertical and horizontal deposition (from fogs, low clouds and rime) and dry deposition of particles and gases in forests. In case of sulphur, its circulation within the forests is negligible; it should provide a good estimate of total deposition.

The fields of dry deposition of Pb and Cd contained in SPM (dry Pb and Cd deposition) were derived from the fields of these metals’ concentrations in the ambient air (or on the basis of air pollution field of annual average of PM10 concentrations and values of IDW interpolation of the shares of the respective metal in dust). The deposition rate of Cd contained in SPM was taken as 0.27 cm.s-1 for a forest and 0.1 cm.s-1 for unforested terrain; the figures for Pb are 0.25 cm.s-1 for a forest and 0.08 cm.s-1 for unforested terrain (Dvořáková et al. 1995).

In 2013 the colour range in legends to deposition maps was changed due to very low deposition levels of most evaluated pollutants, for which the previous colour range was not convenient any more.

The data on precipitation quality are controlled routinely using the method of ion balance calculation. The difference between the sum of cations and the sum of anions in the sample should meet the allowable criteria which differ slightly in various organizations.

Another control is carried out by comparing the calculated conductivity and the measured conductivity which both should also meet the allowable criteria. Analysis of the blank laboratory samples is also used and blank field samples are monitored and assessed continuously. This enables the control of work during sampling and the control of changes occurring due to transport, manipulation, storage and preparation of the samples prior to the chemical analysis.


The development of annual wet deposition of the main elements as measured at selected stations in the Czech Republic (Fig. IX.22) after the decrease of wet deposition of several components (mainly sulphates, hydrogen ions and lead ions) in the second half of the 90’s, shows stagnation instead. The decrease of sulphate deposition was apparent both at the relatively exposed suburban stations and at the background stations, e.g. Košetice and Svratouch.

With the development of sulphur and nitrogen deposition the development of the proportion of both elements can be observed in atmospheric precipitation connected with the development of emissions of individual pollutants (Fig. IX.21). Since the second half of the 90’s a slight increase of nitrates and sulphates proportion has been observed at some stations.


Tab. IX.1 Average deposition fluxes S, N and H in the Czech Republic, 2013

Tab. IX.2 Estimate of the total annual deposition of the given elements on the area of the Czech Republic (78,841 sq. km) in tonnes, 2013

Tab. IX.3 Estimate of the total annual deposition of sulphur on the forested part of the Czech Republic (26,428 sq. km) in tonnes, 2001–2013

Tab. IX.4 Station networks monitoring atmospheric precipitation quality and atmospheric deposition, 2013


Fig. IX.1 Station networks monitoring atmospheric precipitation quality and atmospheric deposition, 2013

Fig. IX.2 Fields of annual wet deposition of sulphur (SO42- - S), 2013

Fig. IX.3 Fields of annual dry deposition of sulphur (SO2 - S), 2013

Fig. IX.4 Fields of annual total deposition of sulphur, 2013

Fig. IX.5 Fields of annual throughfall deposition of sulphur, 2013

Fig. IX.6 Fields of annual wet deposition of nitrogen (NO3- - N), 2013

Fig. IX.7 Fields of annual wet deposition of nitrogen (NH4+ - N), 2013

Fig. IX.8 Fields of annual total wet deposition of nitrogen, 2013

Fig. IX.9 Fields of annual dry deposition of nitrogen (NOx–N), 2013

Fig. IX.10 Fields of annual total deposition of nitrogen, 2013

Fig. IX.11 Fields of annual wet deposition of hydrogen ions, 2013

Fig. IX.12 Fields of annual dry deposition of hydrogen ions corresponding to SO2 and NOx deposition, 2013

Fig. IX.13 Fields of annual total deposition of hydrogen ions, 2013

Fig. IX.14 Fields of annual wet deposition of chloride ions,, 2013

Fig. IX.15 Fields of annual wet deposition of lead ions, 2013

Fig. IX.16 Fields of annual dry deposition of lead, 2013

Fig. IX.17 Fields of annual wet deposition of cadmium ions, 2013

Fig. IX.18 Fields of annual dry deposition of cadmium, 2013

Fig. IX.19 Fields of annual wet deposition of nickel ions, 2013

Fig. IX.20 The development of annual deposition of sulphur (SO42-–S, SO2–S) and oxidated forms of nitrogen (NO3-–N, NOx–N) and hydrogen in the Czech Republic, 1995–2013

Fig. IX.21 The development of the ratio of nitrate/sulphate concentrations in atmospheric deposition (expressed as µeq. l-1) at the CHMI stations, 1998–2013

Fig. IX.22 The development of annual wet deposition at selected stations in 1991–2013, Czech Republic