Assertion: photochemical smog | /r/HasProperty | concern
Facets:
value: in most major urban centres
type: LOCATION
Source sentences:
text: Photochemical smog is a concern in most major urban centres but, because it travels with the wind, it can affect sparsely populated areas as well.
text: Photochemical smog is a concern in most major urban centres but, because it travels with the wind, it can affect sparsely populated areas as well.