Droplets below which diameter remain suspended in the air indefinitely or until they evaporate?

The correct answer is that droplets below 50 microns in diameter can remain suspended in the air for an extended period. This is due to their small size, which allows them to be influenced more by air currents than by gravity. Larger droplets fall to the ground more quickly due to the force of gravity pulling them down, while smaller droplets face less gravitational pull relative to the upward motion of air. As a result, droplets smaller than 50 microns can drift in the atmosphere, allowing for greater dispersion of the pesticide or herbicide being applied. This characteristic is crucial for aerial applicators who aim to maximize the effectiveness of their applications by ensuring that the droplets remain airborne long enough to reach their target areas.

Understanding the behavior of droplets in the air helps aerial applicators make informed decisions about droplet size in order to optimize coverage, minimize drift, and enhance efficacy while adhering to safety regulations.