Description:

Fog occurs primarily due to the condensation of water droplets near the Earth's surface, which significantly reduces visibility. Here’s a breakdown of its causes and impacts:

Causes of Fog:

Condensation of Water Vapor:

When moist air cools to its dew point (temperature at which air becomes saturated), water vapor condenses into tiny droplets, forming fog.

Common in high humidity conditions (e.g., near water bodies, after rain).

Radiational Cooling (Radiation Fog):

On clear nights, the ground loses heat rapidly, cooling the air above it and forming fog (common in valleys).

Advection Fog:

Warm, moist air moves over a cold surface (e.g., sea fog when warm air passes over cold ocean currents).

Upslope Fog:

Moist air rises along slopes, cools adiabatically, and forms fog (common in hilly regions).

Evaporation Fog (Steam Fog):

Cold air moves over warmer water, causing evaporation that condenses into fog (seen over lakes in winter).

Impact on Visibility:

Fog reduces visibility to less than 1 km (dense fog can lower it to near zero).

Disrupts transportation (flight delays, road accidents).

Affects aviation, shipping, and driving safety.

Your Options:

✅ Condensation of water droplets – Correct (main cause).
❌ Increased air pollution – Not a direct cause, but pollutants can form smog (fog + smoke).
❌ Changes in wind direction – Can influence fog movement but don’t directly cause it.