Large inhalable particles exist in the workplace and can constitute a substantial amount of inhaled exposure (50% or more). Particles >20 m primarily deposit in the oro-nasal cavities. Symptomatic health effects (e.g. acute or chronic rhinitis, chronic pharyngitis, chronic sinusitis, nasal cancer, chronic laryngitis and gastro- intestinal diseases) occur in many industries; such effects may be due to the presence of large inhalable particles in these workplaces. However, measurement capabilities for counting and sizing particles between 20 and 100 m are limited. Although large particles settle through air quickly (terminal settling velocity of 100 m particle = 0.3 m/s), these particles are also capabl of delivering very high doses to affected tissues (a 100 m particle weighs approximately 1 g). Thus, a real-time instrument is needed to capture the timing and magnitude of such exposures. There are two specific aims for this project.
The first aim optimizes the design of a portable inhalable particle spectrometer to segregate inhalable aerosols as a function of particle size and incorporates optical detection for real-time measurement of particle size and concentration.
The second aim evaluates the sampling efficiency, cutoff curves, and other performance measures in calm air and low-wind speed environments. The career development plan outlines the activities that will be taken during the K-award period. This plan describes training in three specific skillset areas: engineering design, aerosol optics, and experimental techniques. The career development plan also describes the specific training the mentors will provide, as well as important milestones, steps, and a timeline for achieving the short and long term career goals. One-on-one mentoring (for both research and career development) is described.
Exposure to large inhalable aerosols remains difficult to accurately measure and quantify, which makes it difficult to adequately protect worker health. Effective control methods rely on knowing particle size (cyclone, filtration, ventilation). An instrument capable of accurately measuring particle size will allow practitioners to select appropriate control methods. The aims of this project are to develop and test an instrument capable of measuring large particles.