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Time Weighted Average of Chemical Exposure

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An industrial hygiene survey has been conducted to determine whether exposure of workers to ethyl benzene (molecular weight 106) exceeded the OSHA PEL of 100 ppm. The exposure time and levels are:

Period of Time Average Hourly Exposure
8:00-10:00 am 90 ppm
10:00-12:00 pm 80 ppm
12:30-3:30 pm 110 ppm
3:30-4:30 pm 105 ppm

A. Calculate the 8 hr Time weighted Average (TWA). Show how

B. Was the OSHA PEL exceeded

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This solution explains how to calculated a time weighted average of chemical exposure.

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OSHA PEL
An industrial hygiene survey has been conducted to determine whether exposure of workers to ethyl benzene (molecular weight 106) exceeded the OSHA PEL of 100 ppm. The exposure time and levels are:

Period of Time Average Hourly ...

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