Aside from external factors, which factors primarily affect off-target drift?

The size of spray droplets and the percentage of droplet sizes are critical factors affecting off-target drift because they directly influence how far and how effectively the pesticide can travel once it is released from the applicator. Smaller droplets are more susceptible to drifting due to wind and atmospheric conditions, which can carry them away from the intended application area.

When droplets are larger, they tend to fall more quickly to the ground and are less likely to be carried away by air currents. Conversely, if the majority of droplets are small, the risk of drift increases significantly. Therefore, understanding and managing the sizes of spray droplets when applying pesticides can help minimize off-target movement, ensuring that the application is both effective and environmentally responsible.

Other factors like application technique and timing, weather conditions and humidity, and type of pesticide also influence off-target drift, but they do so in ways that may not be as direct or quantifiable as the relationship between droplet size and drift potential.