You are asked to evaluate employeesâ€™ exposures to methyl n-amyl ketone during a painting operation. After careful consideration, you choose NIOSH Method 2553 for the sampling. You can access the method by clicking the link below:
National Institute for Occupational Safety and Health. (2003). Ketones II: Method 2553. In P. M. Eiler & M. E. Cassinelli (Eds.), NIOSH manual of analytical methods (4th ed.). Retrieved from http://www.cdc.gov/niosh/docs/2003-154/pdfs/2553.pdfÂ
Your pre-sampling and post-sampling pump calibrations using a primary standard are both 0.05 L/min. You collect personal samples on two employees working in the operation. The samples are collected for 430 minutes (Sample 1) and 440 minutes (Sample 2).
- Calculate the sample volumes for each of the samples.
The laboratory reports that the front section of Sample 1 contains 5,000 Âµg of methyl n-amyl ketone and the back section contains 200 Âµg of methyl n-amyl ketone. The front section of Sample 2 contains 4,000 Âµg of methyl n-amyl ketone and the back section contains 50 Âµg of methyl n-amyl ketone. Neither the front nor back sections of the field blank you supplied contain any detectable levels of methyl n-amyl ketone.
- Calculate the concentrations of the two personal samples in Âµg/L and mg/mÂ³.
- Convert the result to ppm (MW for methyl n-amyl ketone = 114.2). Note: Use the ideal gas constant of 24.45.
- Show all the steps for your calculations.
You then reference OSHAâ€™s Table Z-1 and find that the 8-hour TWA PEL for methyl n-amyl ketone is 100 ppm
- Discuss how the results of the two personal samples you collected compare to the OSHA PEL, and describe the sampling method you implemented.
You also look up the ACGIH TLV for methyl n-amyl ketone and find that the TLV is 50 ppm as an 8-hour TWA exposure.
- Discuss how the results for the two personal samples compare to the ACGIH TLV.
- Discuss whether you would recommend comparing the results of your sampling to the OSHA PEL or the ACGIH TLV. Include your rationale for the choice, and explain how you would rationalize your choice to your employer.
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