Disposable filtering facepiece respirators (FFRs) include a wide range of products that may be certified or non-certified. Many of these respirators are being produced with activated carbon claiming nuisance level organic vapor (OV) relief. OV includes a wide range of volatile organic compounds (VOCs) which have been linked to major and minor health discomfort such as headaches, upper extremity discomfort, nausea, respiratory irritation, asthma nervous system complications, hearing loss, cancer, and death. Common industries that have been identified that may expose employees to nuisance level OV, resulting in minor symptoms, include beautician salons, dry cleaning operations, and pesticide applications. FFRs with activated carbon (FFR-AC) may provide a more convenient alternative for reusable respirators which could also protect employees from OV exposure.
This study investigated the adsorption capabilities of one certified respirator (3M) and two alternatively designed respirators (RZ Hunting Mask, Surgical Mask) with activated carbon filtering media. The three FFRs were tested to determine the 50% breakthrough time for two hydrocarbons and one non-carbon-based vapor. 50% breakthrough was chosen because we felt that reducing nuisance level exposures by half would still be protective. Non-certified respirators were exposed to 15 parts per million (ppm) and 50 ppm for all three vapors. Concentrations of 15 ppm and 50 ppm were standardized to achieve similar mass per time exposures across all contaminants and because these values represented the range of nuisance level exposure documented in literature.
The 3M respirator was exposed to 15 and 50 ppm of acetone and ammonia, and perchloroethylene was evaluated at 50 ppm. Perchloroethylene was not evaluated at 15 ppm because breakthrough was longer than 8 hours. 3M respirators were also evaluated at 95% relative humidity using 50 ppm of acetone, ammonia, and perchloroethylene. The total number of trials was 43 (n=43). These contaminants and concentrations were chosen based on published data on occupational exposures.
The non-certified respirators, (RZ Hunting Mask and Surgical Mask) , were ineffective for all vapors and offered less than 10 minutes of protection before 50% breakthrough occurred. Respirators performed poorly, when exposed to ammonia, with breakthrough less than 5 mins at 50 ppm and 10 minutes at 15 ppm. The 3M respirator had the longest breakthrough times for all trials. Acetone breakthrough occurred at 121 minutes for 50 ppm and 233 minutes at 15 ppm. Perchloroethylene took over 400 minutes to achieve 50% breakthrough at 50 ppm. When acetone at 50 ppm and perchloroethylene at 50 ppm were evaluated with 95% R.H. breakthrough times decreased to 39 and 144 minutes respectively, a nearly 70% decrease in time for both vapors.
The results of this study show that non-certified respirators advertised as nuisance level relief may not offer protection for OV. Certified respirators show much more promise, but their performance is highly dependable upon the characteristics of the vapor and environment the respirators are being used in. Additional research is needed to increase our understanding of FFR-ACs performance under more conditions.
| Identifer | oai:union.ndltd.org:uiowa.edu/oai:ir.uiowa.edu:etd-7773 |
| Date | 01 May 2018 |
| Creators | Clinger, Jayson C. |
| Contributors | O'Shaughnessy, Patrick T. |
| Publisher | University of Iowa |
| Source Sets | University of Iowa |
| Language | English |
| Detected Language | English |
| Type | thesis |
| Format | application/pdf |
| Source | Theses and Dissertations |
| Rights | Copyright © 2018 Jayson C. Clinger |
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