ABSTRACT
Exposure to combustion products from wildland fires causes respiratory irritation and decreased lung function among firefighters. The authors evaluated carbon monoxide (CO) exposures of a group of wildland firefighters who conducted prescribed burns in the southeastern United States of America. A total of 149 person-days of samples were collected using data logging CO monitors. A questionnaire was administered to collect data on job tasks and self-reported smoke exposure. Overall, the highest exposures were seen amongst firefighters assigned to holding and mop-up tasks (geometric mean [GM]: 2.6 ppm), whereas the lowest were associated with lighting and jobs such as burn boss (GM: 1.6 and 0.3 ppm, respectively). The self-reported smoke exposure showed a significant linear trend with increasing CO exposure. The numbers of acres burned or burn duration, however, were not good predictors of exposure.
Subject(s)
Air Pollutants, Occupational/analysis , Carbon Monoxide/analysis , Firefighters , Fires , Forestry , Inhalation Exposure/statistics & numerical data , Occupational Exposure/statistics & numerical data , Adult , Environmental Monitoring/instrumentation , Female , Georgia , Humans , Inhalation Exposure/analysis , Male , Occupational Exposure/analysis , Self Report , Smoke/analysisABSTRACT
This paper presents a mathematical model to predict breathing-zone concentrations of airborne contaminants generated during compressed air spray painting in cross-flow ventilated booths. The model focuses on characterizing the generation and transport of overspray mist. It extends previous work on conventional spray guns to include exposures generated by HVLP guns. Dimensional analysis and scale model wind-tunnel studies are employed using non-volatile oils, instead of paint, to produce empirical equations for estimating exposure to total mass. Results indicate that a dimensionless breathing zone concentration is a nonlinear function of the ratio of momentum flux of air from the spray gun to the momentum flux of air passing through the projected area of the worker's body. The orientation of the spraying operation within the booth is also very significant. The exposure model requires an estimate of the contaminant generation rate, which is approximated by a simple impactor model. The results represent an initial step in the construction of more realistic models capable of predicting exposure as a mathematical function of the governing parameters.
