Definition
A form of air pollution consisting of a mixture of smoke, industrial emissions, vehicle exhaust, and atmospheric haze that reduces visibility and can persist near the surface, particularly in urban areas or under stable atmospheric conditions.
Plain English
Dirty, hazy air caused by pollution mixing with the atmosphere. It makes the air look murky and reduces how far you can see through it.
Context Anchor
Encountered in weather and night vision discussions, especially when checking whether visibility will be good enough for safe visual flying.
Derivation
The word is a blend of 'smoke' and 'fog,' coined in the early 1900s to describe the combined effect of coal smoke mixing with natural fog over industrial cities. The blended word matches the blended condition.
Why Pilots Care
Smog scatters city lights and reduces contrast, impairing night vision, making runway lights harder to identify, and raising the risk of disorientation or loss of visual references.
Grounding Statement
At night, smog can make lights look dim, blurred, or farther away than they really are.
Intuition Check
Do not assume smog only matters when it looks thick or brown. In flying, even a thin layer of smog can reduce visibility enough to affect safety.
Example Sentence 1
On the descent into the metropolitan area, smog reduced slant visibility enough that the pilot relied on instruments until closer to the airport.
Example Sentence 2
Even with good weather reports, smog can still reduce night visibility enough to require a switch to instrument references.