"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: Rural – near city: area within 10 km from the border of an urban or suburban area; Rural – regional: 10-50 km from major sources/source areas; Rural – remote: > 50 km from major sources/source areas."(xsd:string)