ympäristöystävällisyys

Noun

 * 1) the state of being environmentally friendly

Usage notes
The term environment friendliness would be understood by English speakers but it seems that it's mostly used in English texts produced in countries where the native language is other than English. The English speakers seem to prefer to express the idea in slightly other words using terms like "care for environment", "sustainability" or "ecological impact", depending on the context.