While generally not harmful, fog's effect on humans is nuanced; it can even be beneficial in certain specific instances.
While dense fog can reduce visibility and cause travel disruptions, potentially leading to accidents, some types of fog, specifically radiation fog, may benefit individuals with respiratory issues by cleaning the air, removing pollutants much like a gentle rain. This benefit, however, is limited and depends on the specific type of fog and the surrounding environmental conditions. It is crucial to differentiate fog from smog, which contains harmful pollutants. Ultimately, fog's overall impact on human health is usually neutral.