1. an unpleasant or harmful odor, discharge, or invisible emanation
Usage: formal; often plural: effluvia
2. a byproduct or waste matter discharged in the course of a process
Usage: technical

Examples

• The effluvium from the chemical plant made residents complain about air quality.
• Noxious effluvia rose from the swamp on hot summer days.
• The factory was cited for releasing toxic effluvium into the nearby river.
• Medieval cities were plagued by the effluvium of open sewers.
• Industrial effluvia contaminated the groundwater supply.
• The effluvium of decay filled the abandoned building.