A natural ventilator is herein disclosed that is free of moving parts, wind-activated, rain-proof, and free of dust or smog infiltration. It is not only suitable to be a standalone natural ventilator, but is also advantageous to be used as an enhanced exhaust exit in a forced-air ventilation system, for such enclosed spaces or objects as buildings and vehicles needing air relief. The ventilator assembly has rainwater-proof shapes or fixtures that serve to defend the vent system, and the interior space being vented, against rainwater invasion, even if raindrop trajectory becomes highly oblique from vertical as driven by strong winds. It also includes shapes or fixtures to prevent fume condensation from drifting outward and staining the exterior of a building or vehicle, or the like, that is being vented.