Droplet-size characterization of handheld atomization equipment typically used in vector control.

The atomization characteristics of 4 handheld sprayers (Leco P-1, Colt ULV Aerosol Generator, ULVAFAN MK2, Turbair ElectraFan 12) and a Stih1 SR400 backpack sprayer were evaluated with the use of water- and oil-based solutions. The effects on droplet-size spectrum (i.e., droplet size) for 3 insecticides (Tempo SC Ultra, Anvil 10+10, and Aqua-Reslin) were also evaluated. Generic solutions were used to simulate the physical properties of the active-ingredient solutions in some tests. Significant differences were observed in the droplet spectrum generated by the different sprayers. The volume median diameter of the equipment tested ranged from 14.9 to 90.5 microm for the water-based solutions and from 11.7 to 92.4 microm for the oil-based solutions. The Colt ULV sprayer was the only one tested that complied with label requirements for aerosols, yielding acceptable Dv0.5 values of 14.9 16.0 microm with water-based Aqua-Reslin and 14.1 microm with Anvil 10+10. The information presented will allow equipment operators to make an informed decision when selecting equipment and operational parameters.