EIONET definitions for Area Classification and Type of Air Quality Stations (used in the eval_new database for CALIOPE NRT evaluation):

=== Type Classification ===

^ Notation ^ Definition ^ URI original source ^
| Traffic | Located in close proximity to a road, in a location that should represent the highest concentrations to which the population are exposed to within the zone. Located such that the pollution level for the specific pollutant is determined predominantly by the emissions from road traffic (i.e. not ship, railway, airplane, off-road) on distinct major roads. As per ANNEX III of DIRECTIVE 2008/50/EC, for all pollutants, traffic-orientated sampling probes shall be at least 25 m from the edge of major junctions and no more than 10 m from the kerbside. | http://dd.eionet.europa.eu/vocabulary/aq/stationclassification/traffic |
| Industrial  | Located in close proximity to single industrial sources or industrial areas, in a location that should represent the highest concentrations to which the population within the zone are exposed to. A wide range of industrial sources can be considered here, including: a) thermal power generation, b) district heating plants, c) refineries, d) waste incineration/treatment plants, dump sites, e) mining, including gravel, oil, natural gas, f) airports or g) ports. | http://dd.eionet.europa.eu/vocabulary/aq/stationclassification/industrial |
| Background | Located such that its pollution levels are representative of the average exposure of the general population within the type of area under assessment. The pollution level should not be dominated by a single source type (e.g. traffic), unless that source type is typical within the area under assessment. The station should usually be representative of a wider area of at least several square kilometers. | http://dd.eionet.europa.eu/vocabulary/aq/stationclassification/background | 


=== Area Classification ===

^ Notation ^ Definition ^ URI original source ^
| rural | All areas, that do not fulfil the criteria for urban or suburban areas, are defined as "rural" areas. There are three subdivisions in this category to indicate the distance to the nearest built-up urban area | http://dd.eionet.europa.eu/vocabulary/aq/areaclassification/rural | 
| rural-nearcity | area within 10 km from the border of an urban or suburban area. | http://dd.eionet.europa.eu/vocabulary/aq/areaclassification/rural-nearcity | 
| rural-regional | 10-50 km from major sources/source areas. | http://dd.eionet.europa.eu/vocabulary/aq/areaclassification/rural-regional | 
| rural-remote | > 50 km from major sources/source areas. | http://dd.eionet.europa.eu/vocabulary/aq/areaclassification/rural-remote | 
| suburban | Largely built-up urban area. ‘Largely built-up’ means contiguous settlement of detached buildings of any size with a building density less than for ‘continuously built-up’ area. The built-up area is mixed with non-urbanised areas (e.g. agricultural, lakes, woods). It must also be noted that ‘suburban’ as defined here has a different meaning than in every day English i.e. ‘an outlying part of a city or town’ suggesting that a suburban area is always associated to an urban area. In our context, a suburban area can be suburban on its own without any urban part. | http://dd.eionet.europa.eu/vocabulary/aq/areaclassification/suburban | 
| urban | Continuously built-up urban area meaning complete (or at least highly predominant) building-up of the street front side by buildings with at least two floors or large detached buildings with at least two floors. With the exception of city parks, the built-up area is not mixed with non-urbanised areas. | http://dd.eionet.europa.eu/vocabulary/aq/areaclassification/urban |