Spatial releasing properties and mosquito repellency of cellulose-based beads containing essential oils and vanillin

Porous cellulose beads (Viscopearl) manufactured from wood pulp can provide gradual-release action for aromatic substances. Here we immersed lemongrass oil, xanthoxylum oil, and vanillin to apply mosquito repellents. The volatiles from this Viscopearl were analyzed to obtain information for quality control (QC) or specification using a GC–MS, and its standard compounds were determined as linalool, geranial, neral, and vanillin. In a test using a 20 L chamber, it was confirmed that their constant amounts were released continuously and they did not be affected by light. In another monitoring test for 47 days on the Viscopearl equipped with a commercialized air conditioner operated for 8 h every day under indoor conditions, the amounts of all released components increased in proportion to the open number of the pores on the module, which is a housing case containing the Viscopearl. In addition, the concentration of 8 major components including 3 standard QC compounds (linalool, geranial, and neral) in a repellency test room depended on both the ventilation and elapsed time. The vapor from the module did not affect main 7 plastic units of the air conditioner, whereas the Viscopearl equipped with an air conditioner showed good mosquito repellency under test chamber and room conditions that temperature, relative humidity, and carbon dioxide concentration were controlled at 24.8–25.4 °C, 63.8–65.7%, and 708–1383 ppm, respectively. Therefore, the plant essential oil-based repellent Viscopearl has high potential to be used as human protective agent against indoor mosquitoes by applying it to air conditioners. [Display omitted] •Viscopearl was immersed with lemongrass oil, xanthoxylum oil, and vanillin.•The standard compounds of Viscopearl were linalool, neral, geranial and vanillin.•Concentration of compounds were depended on both the ventilation and elapsed time.•Viscopearl equipped with air conditioner showed good mosquito repellency.•Viscopearl could be used as a human protective agent against indoor mosquitoes.