Which factor does not influence pesticide drift?

Pesticide drift is primarily influenced by various physical and environmental factors that can affect how pesticides are aerosolized and carried away from the target area. Among the options provided, pollution does not directly impact the mechanics of how pesticides drift through the air.

Particle size is crucial because smaller particles can remain airborne longer and travel farther, increasing the potential for drift. Nozzle design and orientation play significant roles as they affect the size and trajectory of the pesticide droplets being sprayed. Humidity also influences drift, as it can impact the evaporation rates of droplets; higher humidity can lead to larger droplet size and less drift, while lower humidity can cause faster evaporation and smaller, more prone-to-drift particles.

In contrast, pollution mainly refers to the contamination of the air, water, or soil by harmful substances, which while detrimental to the environment and health, does not specifically alter the physical characteristics or behavior of pesticide droplets in the air. Therefore, pollution is not a factor that influences how pesticide drift occurs.