We have a custom built wind tunnel at our facility in Delaware, USA that is vertically oriented. It is used to study droplet size distribution of agricultural sprays. Understanding this distribution is important for overcoming issues such as spray drift. This can occur when agrochemicals are sprayed onto fields but instead of the product reaching its intended end point, it drifts off target. Spray droplets are defined as being susceptible to spray drift if they have a particle size of <105µm, termed driftable fines. Spray nozzles and surfactants will therefore look to increase the particle size of spray droplets outside of this spectrum.