Pasquill atmospheric stability classes &ndash; oldest and, for a great many years, the most commonly used method of categorizing the amount of atmospheric turbulence present was the method developed by Pasquill in 1961. 
He categorized the atmospheric turbulence into six stability classes named A, B, C, D, E and F with class A being the most unstable or most turbulent class, and class F the most stable or least turbulent class. 
* Table 1 lists the six classes 
* Table 2 provides the meteorological conditions that define each class. The stability classes demonstrate a few key ideas. Solar radiation increases atmospheric instability through warming of the Earth's surface so that warm air is below cooler (and therefore denser) air promoting vertical mixing. Clear nights push conditions toward stable as the ground cools faster establishing more stable conditions and inversions. Wind increases vertical mixing, breaking down any type of stratification and pushing the stability class towards neutral (D).
Table 1: The Pasquill stability classes
Table 2: Meteorological conditions that define the Pasquill stability classes
Incoming solar radiation is based on the following: strong (> 700 W m), moderate (350–700 W m), slight ()