Aerosolization of cat dander using robotic vacuum cleaners

<bold>Introduction:</bold> RMT has developed an automated dander aerosolization system using modified robotic vacuum cleaners to evaluate the allergic response to cat. This system aerosolizes dander shed on a carpet by live cats in our Fixed NEC (Naturalistic Exposure Chamber). Milled cat hair from a cannister on the exhaust of the vacuum cleaner and loaded on the carpet was aerosolized in our Mobile NEC. We report the validation of the stability and homogeneity of Fel d 1 levels in the two chambers. <bold>Method:</bold> Temporal stability and spatial distribution of allergen were characterized by measuring airborne Fel d 1 during multiple 2-hour tests. Airborne Fel d 1 was collected using sampling pumps at 3 locations and quantified by ELISA. The sizes and concentrations of aerosolized particulate were measured with an airborne particle counter (Lighthouse, Handheld 3016). <bold>Results:</bold> In the Fixed NEC, average room Fel d 1 concentration during the 2-hour tests was 55 ng/m³ ± 20% and it was evenly distributed across the room, with no statistical differences between three sampling locations. In the mobile NEC, the time-average concentration was 100 ± 24 ng/m³ (mean ± SD) and was dependent on the amount of cat hair on the carpet. There was no difference in the concentrations of particles smaller than 10 μm (aerodynamic particle diameter) but higher concentrations of particles larger than 10 μm occurred in the Mobile NEC than in the Fixed NEC. <bold>Conclusion:</bold> This automated method of dander aerosolization was found to provide stable and homogeneous Fel d 1 levels in both chambers. The system used in a Naturalistic Exposure Chamber provides a controlled but naturalistic means of exposure to pet dander for clinical allergy research.