The FWD requires only that Member States report the methods used to carry out preliminary assessments to the Commission. Member States will need however to retain clear documentation on methods and results for their use in implementing the FWD and daughter legislation, and they may wish to share and exchange this information with other Member States.

It is recommended that the results are documented taking into account minimum quality assurance criteria: the report is dated, the authors and the competent institutions and bodies (art. 3 of FWD) and their addresses are named, and the report is explicitly authorized by the competent authorities.

7.1 Mapping of results

Results are recommended to be primarily produced in the form of maps. Such maps may be produced for each of the quantities/statistics as referred to in limit values and threshold or target values for the pollutant(s) under consideration.

A useful map has a scale such that it clearly shows the limits of the zone, in relation to national and sub-national boundaries. A practical suggestion is to use a normal map as background .

In the zone, areas of exceedance resulting from the preliminary assessment are indicated, either by isolines for the limit value, and for x% and y% of the limit value, or by grid grey scales with a scale enabling to read x%, y% and 100% of the limit value. Here, x% and y% are the upper and lower assessment thresholds levels referred to in article 6.3 and 6.4 of the FWD,

If limit values are expected to be exceeded, it is recommended to indicate the extent of exceedance by the measured or calculated maximum concentration, and/or by isolines indicating suitable multiples of the limit value. Areas of exceedance should be presented on maps with sufficient resolution to see the location of maximum concentrations, in relation to relevant sources and proposed measuring sites. It is recommended to describe and discuss the results as mapped, including uncertainties (see below). Note that different assessment techniques may be used alone or in combination for different parts of the map.

7.2 Documenting of procedures followed

It is recommended to describe and document the work that has led to the map(s). More specifically, the documentation should:

  • describe assessment activities carried out;
  • report specific methods used, with references to descriptions of the method;
  • report sources of data and information.

7.3 Documenting uncertainties

It is desirable to report the most likely total uncertainty in the concentration, either in absolute concentration units, or in relative terms. Uncertainties in, and resulting from emissions, measurements and model results may be presented and discussed separately, and the uncertainties in the mapped quantities (isolines, grid grey scales) may also be estimated. Methodology for this is to be further developed on the basis of expertise and experience in the Member States.

7.4 Updating procedure

It is recommended to update each assessment at the latest 5 years after the date of the initial assessment carried out under the requirements of the FWD, or earlier, if the air quality situation changes appreciably or, in case of revision of the limit or target values.

Appreciable changes to be considered are:

  • changes in the zone of more than (30) % in human activities relevant to emission of the pollutant(s) (traffic volume, industrial production, population number, energy consumption, tourist visits, etc.) or changes smaller than this if they are likely to lead to an exceedance of a limit value or of an upper or lower assessment threshold.
  • major changes in the distribution of emission sources (redesign of road or highway network, closing or establishing of major industrial plants, etc).


SNAP subsector  definition
0101 public power 
0102 district heating plants 
0103 petroleum refining plants 
0104 solid fuel transformation plants 
0105 coal mining, oil and gas extraction / distribution plants 
0201 commercial and institutional plants 
0202 residential plants 
0203 plants in agriculture, forestry and aquaculture 
0301 industry - comb. in boilers, gas turbines & station. engines 
0302 industry - process furnaces without contact 
0303 industry - processes with contact 
0401 processes in petroleum industries 
0402 processes in iron and steel industries and collieries 
0403 processes in non ferrous metal industries 
0404 processes in inorganic chemical industries 
0405 processes in organic chemical industries (bulk production) 
0406 processes in wood, paper pulp, food and drink industry & other industry 
0408 production of halocarbons and SF6 
0501 extraction and 1st treatment of solid fossil fuels 
0502 extraction, 1st treat. and loading of liquid fossil fuels 
0503 extraction, 1st treat. and loading of gaseous fossil fuels 
0504 liquid fuel distribution (except gasoline distribution in 0505) 
0505 gasoline distribution 
0506 gas distribution networks 
0601 paint application 
0602 degreasing, dry cleaning and electronics 
0603 chemicals products manufacturing or processing 
0604 other use of solvents and related activities 
0605 use of N2O, HFC, NH3, PFC or SF6 
0701 passenger cars 
0702 light duty vehicles < 3.5 t 
0703 heavy duty vehicles > 3.5 t and buses 
0704 mopeds and motorcycles < 50 cm3 
0705 motorcycles > 50 cm3 
0706 gasoline evaporation from vehicles 
0707 automobile tyre and brake wear 
0801 other mobile & machinery - military (if not included elsewhere) 
0802 other mobile & machinery - railways 
0803 other mobile & machinery - inland waterways 
0804 other mobile & machinery - maritime activities 
0805 other mobile & machinery - air traffic 
0806 other mobile & machinery - agriculture 
0807 other mobile & machinery - forestry 
0808 other mobile & machinery - industry 
0809 other mobile & machinery - household and gardening 
0810 other mobile & machinery - other 
0902 waste incineration 
0907 open burning of agricultural wastes (except on field 100300) 
0909 cremation 
0910 other waste treatment 
1001 cultures with fertilisers except animal manure 
1002 cultures without fertilisers 
1003 on field burning of stubble, straw
1004 enteric fermentation 
1005 manure management 
1006 use of pesticides and limestone 
1009 manure management regarding nitrogen compounds 
1101 non managed broad-leafed forests 
1102 non managed coniferous forests 
1103 forest and other vegetation fires 
1104 natural grassland and other vegetation 
1105 wetlands (marshes-swamps) 
1106 waters 
1107 animals 
1108 volcanoes 
1109 gas seeps 
1110 lightning 
1111 managed broad-leafed forests 
1112 managed coniferous forests 
1121 changes in forest and other woody biomass stock 
1122 forest and grassland conversion 
1123 abandonment of managed lands 
1124 CO2 emissions from/or removal into soils 
1125 other 



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