Pulmonary deposition of particles in welders: on-site measurements

The authors used integrating nephelometers to demonstrate the feasibility of measuring particulate matter with a diameter of 2.5 microm (PM2.5) in the breathing zone and PM2.5 mass deposition in the airways of 6 welders at their place of work. The authors also measured stationary PM2.5 measurements. The between-subject variation in deposition of PM2.5 mass was approximately 1/3 of the within-subject variation. Smokers had a significantly higher total respiratory system deposition than nonsmokers. The PM2.5 deposition for a given amount of exhaled air was dependent on PM2.5 concentration levels. The estimated total amount of PM2.5 deposited in the respiratory system of the subjects was approximately 1 mg/day.