Final answer:
The three atmospheric conditions for all fog formation are high humidity, presence of condensation nuclei, and cooling of air to the dew point temperature.
Step-by-step explanation:
The three atmospheric conditions necessary for all forms of fog formation are a high level of humidity, sufficient condensation nuclei, and a mechanism to cool the air to its dew point. High humidity is crucial as it determines the amount of water vapor available in the air. The condensation nuclei, such as dust or pollution particles, provide a surface for the water vapor to condense on. Lastly, the air must be cooled to its dew point temperature, which is the temperature at which air becomes saturated and moisture begins to condense, forming fog. Atmospheric conditions such as barometric pressure changes can affect fog formation, but they are not directly responsible for the creation of fog.
Examples of fog formation include a cold front pushing moist air over cooler ground or the collision of warm and cold air masses, resulting in the cooling necessary for fog to form.