Nature and the environment
klimagassn, Emissions to air, air pollution, greenhouse gases (for example CO2, CH4, N2O), emissions by source (for example oil and gas production, road traffic, air traffic), emissions by industry (for example energy sector, manufacturing, primary industries)Pollution and climate, Nature and the environment

Emissions to air


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Emissions to air
Million tonnes CO2 equivalents1Change in per cent
20201990 - 20202019 - 2020
1Greenhouse gas emissions expresses in CO2-equivalents show how much warming effect a greenhouse gas has, converted to the amount of CO2.
Oil and gas extraction13.362.7-4.4
Manufacturing industries and mining11.4-42.2-1.6
Energy supply1.6288.0-1.9
Heating in other industries and households0.6-79.7-18.8
Road traffic8.413.1-3.9
Aviation, navigation, motor equip. etc.8.045.2-3.6

See selected tables from this statistics

Table 1 
Emissions to air of greenhouse gases. Million tonnes CO₂ equivalents

Emissions to air of greenhouse gases. Million tonnes CO₂ equivalents1
Mill. tonnes CO₂ equivalents2
Greenhouse gases totalCarbon dioxide (CO2)Methane (CH4)Nitrous oxide (N2O)Hydrofluoro-carbons (HFCs)Perfluoro-carbons (PFCs)Sulphur- hexafluoride (SF6)
1Does not include ocean transport and international air transport.
2Greenhouse gas emissions expresses in CO2-equivalents show how much warming effect a greenhouse gas has, converted to the amount of CO2.

Table 2 
Emissions to air of greenhouse gases, by source

Emissions to air of greenhouse gases, by source1
Million tonnes CO2 equivalentsMillion tonnes1 000 tonnesTonnes
Greenhouse gases totalCarbon dioxide (CO2)Methane (CH4)Nitrous oxide (N2O)Hydrofluoro-carbons (HFCs)Perfluoro-carbons (PFCs)Sulphur-hexafluoride (SF6)
1Does not include ocean transport and international air transport.
All sources50.042.0180.27.8513.420.52.5
Oil and gas extraction - stationary combustion::::
Oil and gas extraction - process emissions:::
Manufacturing industries and mining - stationary combustion::::
Manufacturing industries and mining - process emissions::::0.0:0.0
Energy supply::::
Heating in other industries::::
Heating in households::::
Passenger cars::::
Light duty vehicles::::
Heavy duty vehicles::::
Motorcycles and mopeds::::
Domestic aviation::::
Costal navigation::::
Motorized equipment etc.::::
Agriculture - enteric fermentation and manure:0.0::
Agriculture - fertilizer and other::0.0:
Landfill gas:::
Road, tyre and brake wear and abrasion of railway contact wires0.
Products containing fluorinated gases, solvents etc.:::::::

Table 3 
Emissions to air of SO₂, NOₓ, NH₃, NMVOCs and CO, by source. 1 000 tonnes

Emissions to air of SO₂, NOₓ, NH₃, NMVOCs and CO, by source. 1 000 tonnes1
1 000 tonnes
Sulphur dioxide (SO2)Nitrogen oxides (NOX)Ammonia (NH3)Non-methane volatile organic compounds (NMVOC)Carbon monoxide (CO)
1Does not include ocean transport and international air transport.
All sources15.8157.628.5152.2400.6
Oil and gas extraction - stationary combustion:::::
Oil and gas extraction - process emissions0.00.00.0:0.0
Manufacturing industries and mining - stationary combustion:::::
Manufacturing industries and mining - process emissions:::::
Energy supply:::::
Heating in other industries:::::
Heating in households:::::
Passenger cars:::::
Light duty vehicles:::::
Heavy duty vehicles:::::
Motorcycles and mopeds:::::
Domestic aviation:::::
Costal navigation:::::
Motorized equipment etc.:::::
Agriculture - enteric fermentation and manure0.0:::0.0
Agriculture - fertilizer and other0.0:::0.0
Landfill gas0.00.00.0:0.0
Road, tyre and brake wear and abrasion of railway contact wires0.
Products containing fluorinated gases, solvents etc.:::::

Table 4 
Emissions to air of particulate matter, by source. 1 000 tonnes

Emissions to air of particulate matter, by source. 1 000 tonnes1
1 000 tonnes
Partic-ulates - TSP2Partic-ulates - PM10Partic-ulates - PM2.5Partic-ulates - TSP2Partic-ulates - PM10Partic-ulates - PM2.5Partic-ulates - TSP2Partic-ulates - PM10Partic-ulates - PM2.5
1Does not include ocean transport and international air transport.
2Total suspended particles.
All sources70.852.241.553.133.825.152.032.724.1
Oil and gas extraction - stationary combustion1.
Oil and gas extraction - process emissions0.
Manufacturing industries and mining - stationary combustion1.
Manufacturing industries and mining - process emissions15.712.
Energy supply0.
Heating in other industries2.
Heating in households24.022.920.714.313.812.713.312.911.9
Passenger cars0.
Light duty vehicles0.
Heavy duty vehicles1.
Motorcycles and mopeds0.
Domestic aviation0.
Costal navigation1.
Motorized equipment etc.
Agriculture - enteric fermentation and manure2.
Agriculture - fertilizer and other0.
Landfill gas0.
Road, tyre and brake wear and abrasion of railway contact wires10.
Products containing fluorinated gases, solvents etc.

About the statistics

The statistics show anthropogenic emissions to air of greenhouse gases, acidifying gases, ozone precursors, environmental pollutants and particulate matter from Norwegian territory. The entire time series for emissions to air was revised in 2018 due to changes in Statistics Norway's energy balance.


Definitions of the main concepts and variables

CO2 equivalents: The GWP value (Global Warming Potential) of a gas is defined as the cumulative impact on the greenhouse effect of 1 tonne of the gas compared with that of 1 tonne of CO2 over a specified period of time. GWP values are used to convert emissions of greenhouse gases to CO2 equivalents.

Substance and GWP value

Carbon dioxide (CO2 ): 1

Methane (CH4 ): 25

Nitrous oxide (N2O): 298

Hydrofluorocarbons (HFCs):

HFC-23: 14 800

HFC-32: 675

HFC-125: 3 500

HFC-134: 1 100

HFC-134a: 1 430

HFC-143: 353

HFC-143a: 4 470

HFC-152a: 124

HFC-227ea: 3 220

Perfluorocarbons (PFCs):

CF4 (PFC-14): 7 390

C2 F6 (PFC-116): 12 200

C3 F8 (PFC-218): 8 830

Sulphur hexafluoride (SF 6 ): 22 800

The national emission model includes four dimensions:

Pollutants: The different gases/substances covered by the emission model

Technical emission sources: Stoves, ships, vehicles, flares, biological and industrial processes

Industry: Standard Industrial Classification (NACE)

Commodity: Different energy commodities; solid fuels (for example coal and coke), liquid fuels (diesel oil, petrol, kerosene, heavy oil etc.), gases (natural gas, landfill gas etc.), biofuel (for instance fuel wood, wood waste, pellets) and waste (hazardous waste and other waste).

Standard classifications

Published tables:

Emission by source

Emission by industry (NACE)

NAMEA (NACE according to Quarterly National Accounts)

Tables used in reports to UNFCCC

Administrative information

Name and topic

Name: Emissions to air
Topic: Nature and the environment

Next release

Responsible division

Division for Energy, Environmental and Transport Statistics

Regional level

National figures

Frequency and timeliness

The figures are published annually in two versions; in May, preliminary figures for the previous year are published. In November, a revised and more detailed version of the same figures are published. At the same time, revised figures for all years back to 1990 are published. The whole time series is recalculated annually as new information becomes available.

International reporting

Annual reports to UNFCCC (United Nations Framework Convention on Climate Change)

Annual reports to Eurostat on emissions from Norwegian economic activity

Annual reports to CLRTAP (Gothenburg protocol)


Not relevant


Background and purpose

The purpose of the statistics is to present the total emissions from Norwegian territory, distributed by sources, industries and energy goods. The statistics also show the achievement regarding the fulfilment of international environmental obligations and national emission targets. In addition, the statistics give information to media, schools, other institutions or organizations, and the public.

The first statistics on emission of CO2 was made in 1987. Since then, methodologies for estimating other emissions have been developed.

The statistics are to a great extent developed in order to cover the demands in the reporting to the protocols under the Convention on Climate Change (UNFCCC). The Norwegian Environment Agency, on behalf of the Ministry of Climate and Environment, is responsible for this reporting. The reported emission figures cover only Norwegian territory, including domestic air and sea traffic. For fishing and road traffic, all emissions originating from fuel sales in Norway are defined as Norwegian emissions.

The statistics can also provide figures on emissions from Norwegian economic activity, as defined in the national accounts. These figures include Norwegian international transport (aviation and navigation) and are used in the environmental accounts (NAMEA) and reports to Eurostat. As the delimitation is different, the emission figures from Norwegian territory and Norwegian economic activity will also differ.

The emission statistics are mainly based on calculations. The emission model is continuously being developed, as research on emissions to air regularly is evaluated. New emission factors are taken into use, errors in the calculations are corrected, and other improvements in the emission model are implemented. These changes lead to new, revised and more consistent time series, and results that are published earlier are no longer valid.

The regular compilation of the statistics is financed by Statistics Norway, but development, improvements and special demands are to a great extent financed by the Norwegian Environment Agency.

Users and applications

The emission inventory and its basic statistics are mainly used for the following purposes:

1. International reporting

2. As a tool for public administration and the authorities

3. Research and education

4. Market, resource and environmental mapping

5. General information

International reporting is an important use of the official statistics. Figures from the emission inventory are being used by the Ministry of Climate and Environment and the Norwegian Environment Agency in reports to UNFCCC. These figures state whether Norway has reached its targets or not. Eurostat, OECD and others are given access to the figures via UNFCCC.

The emission inventory is used by the authorities in environmental information documents, such as the Government's environmental policy, and in different SDIs: Sustainable Development Indicators.

Statistics Norway also makes use of the emission inventory to make forecasts/prognoses, and as a basis for economic analyses. NAMEA (National Accounts Matrix including Environmental Accounts) shows the connection between economic and environmental development.

Public and private institutions use the statistics in studies connected to emission technology, pollution, health and economy.

The emission inventory is an important source of information for the media, environmental organisations and other non-governmental organisations.

Equal treatment of users

No external users have access to the statistics and analyses before they are published and accessible simultaneously for all users on https://www.ssb.no/en at 8 am. Prior to this, a minimum of three months' advance notice is given in the Statistics Release Calendar. This is one of Statistics Norway’s key principles for ensuring that all users are treated equally.

Coherence with other statistics

The statistics are produced in a flexible model format which gives the opportunity to adjust to different national and international standards for emission data. Important international standards include IPCCs CRF classification for reporting to UNFCCC. At the same time, the statistics form a basis for analyses, both in Statistics Norway and other institutions.

Legal authority

Not relevant (no data collection)

EEA reference

Not relevant



The statistics include emissions from Norwegian economic activity (specified under Background and purpose) and present emission surveys for a number of different pollutants:

Greenhouse gases: Carbon dioxide (CO2 ), nitrous oxide (N2O), methane (CH4 ), PFCs (perfluorocarbons), HFCs (hydrofluorocarbons) and sulphur hexafluoride (SF6 ).

Accidification precursors: sulphur dioxide (SO2), nitrogen oxides (NOX), ammonia (NH3)

Non-methane volatile organic compounds (NMVOC)

Carbon monoxide (CO)

Particulate matter (TSP, PM)

Persistent organic pollutants (PAH, dioxines)

Heavy metals: lead, cadmium, mercury, arsenic, chromium, copper

The emission figures are furthermore distributed between emission sources (e.g. manufacturing, road transport, agriculture) or by industry (e.g. metal production, construction).

Data sources and sampling

A detailed description of the data sources for the national air emission surveys is presented in the National Inventory Report (NIR). National emissions to air are mainly estimated from existing statistics on activity level and emission factors (emission per unit activity). Emissions from large industrial plants are based on data from the plants' own reports to the Norwegian Environment Agency.

No measurements or data collection take place in connection with the preparation of national emission statistics.

Collection of data, editing and estimations

Statistics Norway does only to a small extent collect data specifically for the emission inventory. The goal for data collection for the emissions inventory is that these statistics shall be based on already existing registers and statistics. However, it may be necessary to make some adjustments for this special purpose.

Data reported directly to the Norwegian Environment Agency (emission data from point sources, data from large industrial plants) are quality checked by the Norwegian Environment Agency. In addition, a consistency check is done by Statistics Norway. Statistics Norway is responsible for quality control of the activity data and emission figures from the model. Besides data from the energy balance, there are no particular controls performed on data from Statistics Norway's own statistics used in the emission calculations, as it is presupposed that the data already have been quality controlled.

The controls used in connection with the emission calculations can be divided into two parts:

1. Quality control and editing of input data, for example information about emissions per industrial plant from the Norwegian Environment Agency.

2. Quality control and editing of the emission figures (output from the model).

1. Quality control and editing of input data:

The possibility to check the input data varies, depending on the collection methods and who collects the data. The controls will mainly be:

*To compare data with figures reported from the same unit earlier

*To collect missing data

*To contact industrial plants regarding obvious errors or by asking questions about the reported figures

Lack of data in time series can be interpolated or filled in by use of estimates. The primary statistics in SSB are submitted to fixed quality control and editing routines. There is no additional control of primary data.

2. Quality control and editing of the emission figures (output from the model)

The national figures must be controlled source by source, by comparing with figures from previous years or figures for the same year calculated one year ago. Breaks in the series must be explained.

For comparisons between different calculations for the same year, the target is that all changes should be explained as change in data or method. For comparisons between different years, the target is to explain all large changes in the time series.

Annually, there are international examinations (reviews) of the emission inventory, performed by a group of experts nominated by IPCC . 

The emission inventory is mainly based on calculations. Only a few industrial plants continuously measure their emissions. Some plants have periodic measurements that are scaled up to annual levels. For other plants and other sources than manufacturing industries, the emission figures are calculations, often of the type:

Emission = Activity data * emission factor

Activity data can be for example tonnes of fuel oil used by an industry, while the emission factor expresses the emission of a component in proportion to the activity (for example tonnes of SO 2 /tonne fuel oil). The emission factors are usually based on measured values, national or international.

The estimation methods are described in detail in National Inventory Report (NIR).

Seasonal adjustment

Not relevant


The general rule for publication is that data cannot be released unless they contain information from at least three or more participants (i.e. industrial enterprises). This rule can be waived if permission from the parties involved is granted. Such data can be published if they are already made available for the public elsewhere.

Comparability over time and space

One of the main goals for the emission inventories is to follow the development in the emissions over a period. To make this possible, recalculations are done for all years to obtain consistent time series when new factors or better methods are taken into account.

International definitions, in addition to international guidelines for calculation and reporting of emission data, lead to comparable emission inventories in the different countries.

Accuracy and reliability

Sources of error and uncertainty

The emission figures are based on many different data sources. These sources may contain data from different registers or data reported from industrial plants. The model uses factors from various analyses. The results from the model will therefore reflect the uncertainties in the source material and the calculation methods that are used.

The statistics are based both on administrative sources, complete surveys and sample surveys. Calculation of sample variance, skewness or non-response for the emission figures is not relevant.

On a national level the pollutants have been ranked according to uncertainty in  National Inventory Report (NIR) as follows:

Greenhouse gases:

CO 2  ≈ SF 6 < HFCs < PFCs ≈ CH 4 < N 2 O

The uncertainties in the greenhouse gas emission figures are quantified in i.a. Flugsrud and Hoem (2011).


In December each year the emission statistics published in May is revised. Data back to 1990 is also revised if new information about emission factors, activity data or calculation methodology is available.