We don't have synonyms for obscurations yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are obscuration, obsecrations and osculations.
(n) :
A unit of measurement used in particular for smoke detectors which respond to absorption of light by smoke, in percent absorption per unit length, e.g. % obs/ft, % obs/m.
(n) :
A unit of measurement used in particular for smoke detectors which respond to absorption of light by smoke, in percent absorption per unit length, e.g. % obs/ft, % obs/m.