Characterization of Chemical Aerosols Generated Using Commercially Available Liquid Aerosol Generators

OYEDOYIN ADUROJA, Kalia Robinson, Cathy S. Scotto, Vasanthi Sivaprakasam, US Naval Research Laboratory

     Abstract Number: 642
     Working Group: Aerosol Chemistry

Abstract
We are evaluating a range of commercially available liquid aerosol generators to produce chemical aerosols of controlled characteristics such as aerosol size, mass and concentration. For our current program of interest, we generate simulant aerosols representing various classes of chemicals of interest. Simulants for chemical classes such as caffeine and acetaminophen and inert materials such as NaCl, kaolin and Arizona road dust are used to evaluate the aerosol generator properties. The material of interest is dissolved in water or appropriate solvent and used to generate droplets from the various generators. The generated droplets are dried in an air column and the resultant dry aerosol size distribution and concentration is characterized using particle sizers.

Various types of generators studied here includes atomizing nozzles, atomizing liquids impacted onto hard and soft surfaces, ultrasonic nozzles, and vibrating mesh-based devices. The concentration of the starting chemical solution, the median and width of the droplets generated, the rate of air flow and frequency of operation impacts the characteristics of the resultant dry aerosol. Laboratory studies will be conducted to quantify the range of aerosol size, mass and number concentration achievable for the chemical classes of interest. A numerical analysis has been conducted to characterize the properties of the aerosol for the various generators and will be validated with the experimental results. The analysis and the laboratory results will be presented at the conference.