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?

• 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
8

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?