id	keyword
essd-556	areas
essd-556	innovation
essd-556	development
essd-556	cities
essd-556	patents
essd-556	environmental
essd-556	value
essd-556	quality
essd-556	sustainability
essd-556	data
essd-556	study
essd-556	model
essd-556	metropolitan
essd-556	air