Understanding the chemical and physical characteristics of a pesticide allows the applicator to make better decisions about which pesticide active ingredient and/or formulation to use for a particular situation. Two chemical characteristics of interest are water solubility and volatility. The more water soluble a pesticide is, the greater the potential for runoff and leaching. The more volatile a pesticide is, the greater the potential for drift.
Pesticide drift occurs when pesticides are transferred in air away from the intended application site into adjacent areas. Pesticides can move as spray droplets, vapor drift, or solid particle drift.