What atmospheric conditions would provide the greatest air density?

The greatest air density occurs under conditions of cold temperature, high static pressure, and low humidity. Cold air is denser than warm air because the molecules are packed more closely together as the temperature decreases. Additionally, high static pressure contributes to higher air density; as atmospheric pressure increases, it compresses the air and increases density.

Low humidity also plays a role in increasing air density. Water vapor is lighter than the oxygen and nitrogen molecules that make up most of the atmosphere. Therefore, when humidity is low, the proportion of denser air (oxygen and nitrogen) increases, leading to higher overall air density compared to a humid atmosphere, which contains more water vapor.

Combining these conditions—cold temperature, high static pressure, and low humidity—results in the most favorable scenario for achieving the highest air density.