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Emissions of heavy metals

Last update of indicator08.01.2024

Indicator definition

The indicator describes the development of heavy metals emissions (Pg, Hg, Cd), including a comparison with the fulfilment of obligations under the international conventions.


g, %, t, kg, kt


Related policy documents and targets

Convention of European Economic Commission  of the United Nations on Long-Range Transboundary Air Pollution (Geneva, 1979)
The Slovak Republic is a party to the Convention by the United Nations Economic Commission on Long Range Transboundary Air Pollution, and it has subscribed to the commitments under the following Protocols:
Protocol to Abate Acidification, Eutrophication and Ground-Level Ozone (1999)
The SR´s commitment is to reduce SO2 emissions up to 2010 by 80%, NO2 emissions up to 2010 by 42%, NH3 emissions up to 2010 by 37%, and NM VOC emissions up to 2010 by 6% - compared to 1990. In 2012, a revision was made to the objectives of the Protocol to reduce emissions in 2020, compared with the base year 2005 as follows:

Pollutant SO2 NOX NMVOC NH3 PM2.5
%  of reduction 57 36 18 15 36

Protocol to abate acidification, eutrophication, and ground-level ozone sets the following measures for meeting the objectives as follows: 
• to develop new projections of pollutant emissions included in this Protocol by 2010,
• based on these projections prepare the analysis of the possibility of introducing quotas for individual pollutants (for SO2 the emission quotas are already established),
• to implement Directive 94/63 EC, 1999/13/EC on volatile organic compounds and Directive 2001/80/EC on the limitation of emissions of certain pollutants from large combustion plants.

National reduction commitments

National emission reduction commitments for individual Member States are set out in Annex II of the NEC Directive. They are expressed as a percentage reduction in emissions of the monitored pollutants compared to the base year 2005. Emission reduction commitments are set in two phases: (a) commitments in force for 2020 and subsequent years up to 2029 (by the commitments set out in the Appendix to the Protocol on the Reduction of Acidification, Eutrophication, and Ground-Level Ozone to the 1979 Convention on Long-range Transboundary Air Pollution (Appendix to the Gothenburg Protocol)) a (b) more stringent commitments in force since 2030 and beyond. Emission reduction commitments established for the Slovak Republic are shown in Table 1. National emission reduction commitments under the NEC Directive for the Slovak Republic National reduction commitments of the Slovak Republic compared to the base year 2005

National obligations to reduce emissions according to the NEC directive for the Slovak Republic

National reduction commitments of the Slovak Republic compared to the base year 2005
(v %)
Commitments valid for 2020 and subsequent years until 2029 57 36 18 15 36
Commitments valid for 2030 and following years 82 50 32 30 49



Protocol on Heavy Metals to the UNECE Convention on Long Range Transboundary Air Pollution (1998)
sets goals to reduce emissions of heavy metals (Pb, Cd, Hg) to the emission level of 1990. The Slovak Republic signed this Protocol in the same year, when it was also signed.

European Green Deal (2019)
It is necessary to review policies in the area of clean energy supply for the entire economy, as well as in the areas of industry, production and consumption, general infrastructure, transport, food and agriculture, construction, taxation, and social benefits. To achieve these goals, it is necessary to increase the perceived value of protecting and restoring natural ecosystems, sustainable use of resources, and human health. This is where transformative change is most needed and potentially most beneficial for the EU's economy, society, and environment.

2.1.3. Mobilization of industry in the interest of a clean and circular economy
The Commission will draw on the experience it has gained in evaluating current air quality legislation. In addition, it will propose strengthening provisions on air quality monitoring, modeling, and plans to help local authorities achieve cleaner air. In particular, the Commission will propose a revision of air quality standards to better align them with the recommendations of the World Health Organization

2.1.5. Accelerating the transition to sustainable and intelligent mobility
Traffic pollution should be radically reduced, especially in cities. The issue of emissions and congestion in cities, as well as the improvement of public transport, should be solved by a combination of several measures. In the case of vehicles with a combustion engine, the Commission will propose stricter standards for emissions of air pollutants

2.1.8. The ambition of zero pollution for a non-toxic environment
The Commission will draw on the experience it has gained in evaluating current air quality legislation. In addition, it will propose strengthening provisions on air quality monitoring, modeling, and plans to help local authorities achieve cleaner air. In particular, the Commission will propose a revision of air quality standards to better align them with the recommendations of the World Health Organization

Greener Slovakia – Environmental Policy Strategy of the Slovak Republic until 2030 (Envirostrategy 2030) (2019)
The environmental strategy is a basic strategic document for the environment with long-term goals aimed at the transition to a green, low-carbon, and inclusive economy. The Envirostrategy 2030 defines the vision until 2030 (to achieve a better quality of the environment and a sustainable circular economy using as few non-renewable natural resources and hazardous substances as possible), identifies basic systemic problems, sets goals for 2030, and proposes framework measures to improve the current situation.

Clean Air Goals:

  •      Air quality in 2030 will be significantly better and will not have a significantly adverse effect on human health and the environment. This will be achieved by reducing the amount of emissions compared to 2005 - SO2 by 82%, NOx by 50%, NMVOC by 32%, NH3 by 30% and PM2.5 by 49%
  •      Promote more efficient combustion devices and heating systems
  •      Gradually reduce the production of electricity from coal
  •      Increase the share of low-emission transport


National emission reduction program of the Slovak Republic (2020)
Among the biggest environmental challenges of the Slovak Republic are also the goals based on Directive (EU) 2016/2284 on the reduction of national emissions of certain air pollutants, which amends Directive 2003/35/EC and repeals Directive 2001/81/EC.
These are commitments to reduce emissions of sulfur oxides, nitrogen oxides, non-methane volatile organic compounds, ammonia, and PM2.5 dust particles by 2030. To achieve these goals, the MoE of the Slovak Republic has currently developed a draft of the National Emissions Reduction Program, in which policies and measures for achieving the aforementioned national commitments in two stages: the period from 2020 to 2029 and the period from 2030 onwards.
The National Emissions Reduction Program contributes to the achievement of air quality targets under Directive 2008/50/EC, as well as ensuring compliance with plans and programs set out in other relevant policy areas, including climate, energy, agriculture, industry and transport. At the same time, this will support the transfer of investments into clean and efficient technologies.



Key question

What is the development of heavy emissions?

Key messages

  • In the case of heavy metals (Cd, Hg, Pb), a trend of a significant decrease in their emissions was recorded in the long term, but in the short term, compared to 2020, emissions of Hg, Cd increased slightly, and emissions of Pb even recorded a significant increase.


Zmena od roku 2005 Zmena od roku 2015 Posledná medziročná zmena Pokrok pre dosiahnutie konkrétneho stanoveného cieľa
Pozitivny trend Pozitivny trend emo_sad Pozitivny trend
A significantly decreasing trend was recorded in the case of PCDD/F and PAH emissions, PCB emissions slightly increased. The downward trend continues, the overall development can be considered positive. In 2021, compared to 2020, emissions of heavy metals (Pb, Hg, Cd) increased. The Slovak Republic is succeeding in meeting the goals of its international obligations.


Summary assessment


For the current fulfillment of legislative obligations, the year 2005 is important, which in terms of comparison is considered basic or reference (i.e. the decrease in emissions is compared with 2005). The nature of the pollutant emission trend starting this year is decreasing in most sectors of the economy as a result of legislative measures, the introduction of new technologies, as well as for economic reasons. However, the decline has slowed in recent years.

Detailed assessment

The evaluation of the emission situation is processed on the basis of emission inventories resulting from the Convention on Long-Range Transboundary Air Pollution (CLRTAP) and thus according to the NFR categorization of sources (NFR - Nomenclature for Reporting).

By comparing the years 2005-2021, a significant decrease in emissions of basic pollutants was found. In the year-on-year comparison (2020 – 2021), there was a slight increase in emissions of all monitored pollutants, except for NH3 emissions, which decreased slightly. This positive development trend was recorded as a result of legislative and technological progress and a change in the fuel base. Changes in the structure and volume of industrial production also had an impact on the development.

Hg emissions [kt/year] by sectors of their origin in 2021

  2005 2010 2015 2016 2017 2018 2019 2020 2021
Energy 0,580 0,326 0,285 0,266 0,267 0,259 0,260 0,268 0,274
Huoseholds 0,089 0,081 0,066 0,068 0,075 0,065 0,066 0,066 0,072
Transport 0,013 0,014 0,014 0,015 0,015 0,015 0,016 0,014 0,015
Agriculture 0,000 0,000 0,000 0,000 0,000 0,000 0,000 0,000 0,000
Industrial processes and product use 0,124 0,116 0,127 0,128 0,128 0,128 0,125 0,115 0,124
Waste 0,063 0,023 0,027 0,027 0,023 0,029 0,032 0,037 0,050
Total 0,869 0,559 0,520 0,503 0,509 0,495 0,499 0,500 0,535

Pb emissions [kt/year] by sectors of their origin in 2021

  2005 2010 2015 2016 2017 2018 2019 2020 2021
Energy 9,582 1,869 1,714 1,505 1,516 1,433 1,369 1,267 1,406
Households 0,478 0,477 0,397 0,437 0,445 0,354 0,380 0,380 0,436
Transport 0,670 0,732 0,807 0,867 0,841 0,907 0,928 0,831 0,886
Industrial processes and product use 6,357 4,984 5,436 5,693 6,161 5,581 4,471 3,279 5,415
Agriculture 0,000 0,000 0,000 0,000 0,000 0,000 0,000 0,000 0,000
Waste 0,044 0,010 0,011 0,005 0,005 0,008 0,008 0,007 0,005
Total 17,130 8,073 8,366 8,508 8,968 8,283 7,156 5,764 8,148

Cd emissions [kt/year] by sectors of their origin in 2021

  2005 2010 2015 2016 2017 2018 2019 2020 2021
Energy 0,428 0,205 0,248 0,218 0,229 0,203 0,207 0,209 0,205
Households 0,304 0,309 0,243 0,267 0,263 0,206 0,224 0,226 0,257
Transport 0,004 0,004 0,004 0,005 0,005 0,005 0,005 0,004 0,005
Industrial processes and product use 0,207 0,254 0,146 0,150 0,158 0,147 0,130 0,112 0,154
Agriculture 0,000 0,000 0,000 0,000 0,000 0,000 0,000 0,000 0,000
Waste 0,005 0,002 0,002 0,002 0,002 0,002 0,002 0,002 0,002
Total 0,947 0,773 0,643 0,641 0,656 0,562 0,567 0,554 0,622

Development of heavy metal emissions

When comparing the years 2005 and 2021, a decrease in Pb emissions by 52.4%, Hg by 39% and Cd by 34.7% was recorded. In 2021, compared to 2020, a slight increase was recorded in the case of Hg, Cd emissions, and in the case of Pb emissions, the increase was even more significant. In addition to the tightening of the relevant legislation, the aforementioned development was also influenced by the shutdown of outdated production, the decline in industrial production and the transition to the use of unleaded gasoline. Industry mainly contributes to heavy metal emissions, in the case of cadmium it is the production of copper, and in the case of lead and cadmium the production of iron and steel.

There was a significant change in the methodological procedure for the inventory of heavy metals. In previous years, the emission factors from 1992 were used in the calculations, and currently the emission factors were changed to those that are current and comparable with other countries in the EU. In historical years for Cd emissions, last year's emission factors significantly overestimated emissions from the glass production source, emission factors for the same technology are several times smaller according to newer methodological procedures. The most significant source of Cd emissions has changed from glass production to copper production, the production of which is increasing. The order of the key categories has completely changed due to the change in methodology for heavy metals, therefore the current resulting emissions do not yet take into account the impact of separation technologies. This should change in most important categories in next year's inventory.


Ing. Dorota Hericová, SAŽP,

Definitions related to the indicator:

An emission is any direct or indirect release of a polluting substance into the air.

Pollutants in the air include solid pollutants (particulate matter - PM), sulfur dioxide (SO2), nitrogen oxides (NOX) and carbon monoxide (CO), volatile organic compounds (NMVOC), ammonia (NH3), persistent organic compounds ( POPs) and heavy metals (Hg, Cd, Pb). Pollutant emissions are divided into emissions emitted from stationary sources (production and distribution of electricity, steam and hot water, local heating equipment, industrial technological processes, extraction of fossil fuels, landfills and waste processing, agricultural production, other stationary sources) and mobile sources ( road transport and other mobile resources).

Heavy metals (Hg, Pb, Cd) are metals or in some cases semi-metals that are stable and have a density greater than 4.5 g/cm3 including their compounds.

Heavy metals (such as cadmium, lead and mercury and others). All are susceptible to biomagnification, that is, they accumulate progressively higher up the food chain, so bioaccumulation in lower organisms at relatively low concentrations can expose higher consumer organisms, including humans, to potentially harmful concentrations. They can have carcinogenic effects, or affect the immune system and the ability to reproduce. They can have a harmful effect even at low concentrations.


Basic data on individual stationary sources of air pollution (hereinafter referred to as "POPs") in the Slovak Republic began to be collected in the 1980s. and were stored in the Register of Emissions and Sources of Air Pollution (REZZO). Fundamental changes in the 1990s required the creation of a new information system for the registration of ZZO. Since 2001, the National Emission Information System (NEIS) has been used for this purpose, which has undergone many changes since then, has been supplemented with new functions several times, and separate modules have been added to it. At its inception, the NEIS was mainly used to calculate the amount of emissions and the amount of the fee for air pollution. Today it is already used as an important (in some cases the only) source of a wide range of data (amounts of emissions of polluting substances released into the air per year, the amount of fuel burned, parameters of combustion and technological equipment, etc.). Pursuant to the mandate of the Slovak Ministry of the Environment, NEIS is managed by the Slovak Hydrometeorological Institute.
Currently, the system consists of a module for district offices (OÚ), the NEIS PZ WEB portal for ZZO operators ( and a central module at SHMÚ for creating user outputs. The selected data are published on the website, where the user can create his own output reports after free registration.

Data are collected in the NEIS, which are based on two notification obligations of operators of ZZO:

     according to § 24 of Act no. 146/2023 Coll. on air protection,
     according to § 5 of Decree 254/2023 Coll. which implements some provisions of the Air Protection Act

The data is reported to the relevant district office directly by the operators, and the initial processing of the data is carried out by an employee of the OU. The summary annual evaluation of the operational records of all large and medium-sized ZZO in the district for the previous year is submitted by the OU to the authorized organization (SHMÚ) in electronic form by May 31 of the current year. SHMÚ further processes, analyzes, checks and corrects the data in the system if necessary - in cooperation with the relevant OU. This centralized control takes place every year until the end of October. The control is followed by the processing of a number of output reports.
§ 23 of Act no. 149/2023 Coll. on air protection precisely establishes and describes the requirements for determining the amount of emissions.

Data source:
SHMÚ, Eurostat

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