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D-limonene emission factors from a terpene electronics parts degreaser.

Keil CB; Franke JE; Wadden PA; Scheff PA; Conroy LM
American Industrial Hygiene Conference and Exposition, May 15-21, 1993, New Orleans, Louisiana. Fairfax, VA: American Industrial Hygiene Association, 1993 May; :57-58
The phase-out of ozone depleting chloroflourocarbons (CFCs) called for in the Montreal protocol has led to a search for alternative compounds for use in various industrial processes. Terpenes are a potential replacement for CFCs in metal and electronics cleaning applications. Terpenes are a naturally occurring compound found in citrus oil. As a class of compounds terpenes have excellent solvency, rinsability, wetting, penetrating and detergent characteristics. They are considered to have low to moderate toxicity based on an incomplete but growing data base. Commercial formulations of terpenes have caused contact dermatitis and the odor is reported to produce a range of effects from headaches to nausea. Animal studies indicate that two of the terpenes, d-Iimonene and anethole are hepatotoxic to rodents. This study evaluated the emissions of d-Iimonene, the most abundant of the terpenes, around a conveyerized computer board degreaser. The degreaser was part of a prototype production facility in a 114,897 ft room. The degreaser was originally designed for use with aqueous cleaners. A commercial cleaner (90% terpene, 10% anionic surfactant) was used in the unit on a trial basis. The degreaser consisted of an enclosed terpene spray wash side followed by an enclosed hot water. spray rinse side with an air knife and drying oven at the exit end of the conveyor. The degreaser was equipped with local exhaust ventilation (LEV) on both enclosed spray sides and included a canopy hood over the open conveyor section between the two sides. Sulfur hexaflouride (SF6) tracer gas studies were done to determine the effective air flow through the room. The effective airflow through the room was 10,946 cubic feet per minute or 5.7 air changes per hour. Air samples were collected at eight locations around the room including LEV ductwork. A short term sample was collected prior to the start of degreasing operations. This background d-limonene concentration was 0.03 mgfm3. The average room concentration during degreaser operation was 0.53 mgfm3. The LEV -captured d-limonene emissions were calculated using duct concentrations and duct flowrate. The average captured emission rate was 11,263 mg/min. These emissions were found to be strongly correlated with board throughput and can be described as mg emitted = 2,181 x number of boards degreased + 10,204 (r2 = 0.96). Board throughput varied from 0 to 57 boards per hour with an average of 29 boards per hour.
Ozone; Emission sources; Terpene compounds; Terpenes; Metal compounds; Metallic compounds; Cleaning compounds; Solvents; Contact dermatitis; Odors; Animals; Laboratory animals; Hepatotoxins; Ventilation; Air flow
Publication Date
Document Type
Funding Amount
Funding Type
Cooperative Agreement; Construction; Grant
Fiscal Year
Identifying No.
Cooperative-Agreement-Number-U60-CCU-306169; Grant-Number-R01-OH-002804
Source Name
American Industrial Hygiene Conference and Exposition, May 15-21, 1993, New Orleans, Louisiana
Performing Organization
Center to Protect Workers' Rights, Washington, DC
Page last reviewed: May 11, 2023
Content source: National Institute for Occupational Safety and Health Education and Information Division