1) You are an industrial hygienist conducting personal sampling on a worker who is overseeing a production process involving use of acetone (Note: The Occupational Safety and Health Administration has established a Permissible Exposure Limit of 1000 parts per million (ppm) of acetone). You are able to measure the following exposures:

700 ppm for 3 hours

1300 ppm for 2 hours

900 ppm for 3 hours

What is the calculated TWA? What would you tell plant management in terms of exposure to acetone and compliance with the PEL?

2) Please solve the following problem, indicating your response on a Word document and submitting the document via File Upload.

Using the following formula, solve the problem below, and show your work.

TWA = CaTa + CbTb + ... + CnTn

TWA = Time-Weighted Average
Ca = Concentration of contaminant during the sampling period "a"
Ta = Time of sampling period "a"
Cb = Concentration of contaminant during the sampling period "b"
Tb = Time of sampling period "b"
Cn = Concentration of contaminant during the sampling period "n", where "n" is the last of a series of contaminants
Tn = Time of sampling period "n"

Note: All concentrations are in parts contaminant per million parts of air or milligrams of contaminant per cubic meter of air.

Air Sampling Problem: You are an industrial hygienist that is conducting personal sampling on a worker who is overseeing a production process involving use of toluene (Note: The Occupational Safety and Health Administration has established a Permissible Exposure Limit of 200 parts per million (ppm)). You are able to measure the following exposures:

500 ppm for 1 hour

100 ppm for 4 hours

225 ppm for 3 hours

What is the calculated TWA? What would you tell plant management in terms of exposure to toluene and compliance with the PEL?