What type of air is associated with good days of visibility?

Stable air is associated with good visibility primarily because it tends to inhibit vertical motion in the atmosphere. This stability allows pollutants and moisture to disperse more evenly, resulting in clearer skies and better visibility. In stable conditions, the air is typically stratified, meaning there are fewer disturbances that could lead to the formation of clouds or haze. Low-level clouds or fog, which can occur in unstable or moist conditions, are less prevalent in stable air, contributing further to good visibility.

Moist air can lead to reduced visibility due to the potential for cloud formation and fog, while dry, unstable air is often characterized by turbulence and vertical lift, which can promote the creation of clouds, ultimately reducing visibility. Warm, humid air can also lead to weather phenomena like fog or thunderstorms that impair visibility. Therefore, stable air is the best choice for conditions that favor clear visibility.