For optimal paint transfer from the spray nozzle to the car body surface, the ideal humidity level is 72% relative humidity. Under these conditions, paint evaporation is minimized, ensuring that the paint reaches the car body as intended by the manufacturer. Additionally, controlling humidity reduces the amount of paint dust entering the spray booth. During sanding processes, maintaining a relative humidity of 55% decreases dust accumulation and static charge. This prevents airborne paint dust from adhering to the car body surface, speeding up the sanding process and ultimately providing a higher quality finish.