The research proposed here will provide comprehensive data on inhalability and personal sampler performance over the particle size range of 10 to 150 micromoles for a wide range of exposure conditions, for liquid and solid particles, and for mouth and nose breathing. Exposure to large particles, 10-150 micromoles, occurs in occupational activities such as mining, woodworking, painting, pesticide application, grinding, and mineral processing. Generally, large particles such as heavy metals, pesticides, radioactive materials, and corrosives are harmful if inhaled, regardless of where they deposit in the respiratory system. Occupational health professionals need to know what fraction of large particles will be inhaled under different conditions, and how well different types of samplers collect these particles. Few data are available on the inhalation of large particles and the performance of samplers for these particles. For example, for particles greater than 30 micromoles, there are no data on inhalability for liquid particles, for nasal inhalation, and for sampling performance of 37 mm filter cassettes. Data for solid particles greater than 60 micromoles come from only one laboratory. Experimental measurements of these quantities under simulated industrial conditions are needed to support standards based on recent ACGIH and CEN sampling criteria for inhalable particulate matter (IPM). The proposed research will be conducted using UCLA's fully operational low-velocity wind tunnel to simulate, under controlled conditions, air motion typical of indoor work environments. Specific test conditions for solid and liquid particles are: eight particle sizes (10-150 micromoles), three air velocities (0.4-1.8 m/s), three breathing profiles (work rate of 0-102 W), two orientations (0 degrees and orientation average), and three replications for each condition. Personal sampler evaluation will include current """"""""total,"""""""" IPM, and prototype IPM samplers over the same range of conditions for solid and liquid particles.
