Estimating the contribution of individual work tasks to room concentration: method applied to embalming.
Bennett-JS; Feigley-CE; Underhill-DW; Drane-W; Payne-TA; Stewart-PA; Herrick-RF; Utterback-DF; Hays-RB
Am Ind Hyg Assoc J 1996 Jul; 57(7):599-609
A new approach for estimating emission rates of a pollutant from monitoring data and estimating the contribution of individual work tasks to pollutant concentrations in workplace air was developed and applied to formaldehyde (50000) exposures in an embalming room. Formaldehyde concentrations at various work stations were measured during 25 embalmings at a college of mortuary science. Formaldehyde emission rates were calculated as the first derivative of the concentration with respect to time utilizing a formaldehyde mass balance relationship in which the rate of emission was set equal to the sum of the rate of formaldehyde buildup in the room and the rate of removal in the exhaust flow. Formaldehyde generation rates were then computed for 29 work tasks or events using an equation that incorporated the buildup and decay of formaldehyde concentrations in the workroom air utilizing nonlinear regression techniques. Each term representing one of the work tasks or events was integrated using the gamma function. This yielded the contribution of the formaldehyde exposures associated with the task or event to the total formaldehyde concentration in the room. The four work tasks or events that were identified as making the largest contribution to room formaldehyde concentrations were aspirating viscera after treatment with cavity fluid, an accidental spill of embalming fluid, application of osmotic gel, and infusion of the trocar cavity. These were associated with formaldehyde generation rates of 8, 22, 37, and 27 milligrams (mg) per minute and integrated formaldehyde exposures of 66, 61, 51, and 41mg, respectively. The authors conclude that this type of analysis can identify the relative importance of individual work tasks or events as contributors to workroom pollutant concentrations.
NIOSH-Author; Indoor-air-pollution; Formaldehydes; Emission-sources; Occupational-exposure; Workplace-monitoring; Mathematical-models; Air-monitoring; Work-analysis; Indoor-environmental-quality;
Author Keywords: embalming; emission rates; exposure; formaldehyde; mathematical model; nonlinear regression
Charles E. Feigley, University of South Carolina School of Public Health, Department of Environmental Health Sciences, Health Sciences Building, Room 311, Columbia, SC 29208
American Industrial Hygiene Association Journal