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

TWA = C_aT_a + C_bT_b + ... + C_nT_n

TWA=Time-Weighted Average
C_a=Concentration of contaminant during the sampling period "a"
T_a=Time of sampling period "a"
C_b=Concentration of contaminant during the sampling period "b"
T_b=Time of sampling period "b"
C_n=Concentration of contaminant during the sampling period "n", where "n" is the last of a series of contaminants
T_n=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?

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?

Discuss the effects that extreme temperatures can have on the human body. How can an individual protect himself/herself from these effects?

Heat stress, heat stroke, heat exhaustion, heat cramps, cold stress. Joel M. Haight Recognition, Evaluation and Control of Workplace Health Hazards.

Describe how noise and vibration hazards can affect the human body. What are some methods for mitigating these hazards?