Abstract:
Emissions into the environment, or workplace, of toxic air contaminants that have adverse human health effects are of concern for safety and regulatory reasons. The American Conference of Governmental Industrial Hygienists (ACGIH) annually publishes a Threshold Limit Value (TLV) booklet that lists a TLV for approximately 600 hazardous chemicals. The TLV is considered to be the maximum chemical concentration that a worker may be exposed to averaged over an 8-hour work shift and not suffer any adverse health effects. About 25%, or 150, of all chemicals with TLVs also have Short-Term Exposure Limits (STEL) or ceiling values. The STEL is the maximum chemical concentration that a worker can be exposed to for any 15-minute interval during the work shift before the worker is required to leave that area. A ceiling value is maximum concentration that is never to be exceeded.
Currently, a variety of personal and area air sampling methods have been developed to address the need for identifying and quantifying the concentration of airborne chemicals. Advantages of personal samplers, such as charcoal sorbent tubes or passive badges, include their relatively light weight and the results are easy to apply to decision making. However, they average the exposure does over the entire sampling period and the resulting time weight average may not accurately capture STELs or ceiling values. STELs and ceiling values maybe difficult to determine for a variety of reasons, including the timing of the sampling, location of the point sampler or the need to sample for multiple chemicals with different sampling methods. Also, charcoal sorbent requires shipment to a laboratory for chemical analysis during which sample losses could occur, may involve substantial cost, and a worker could be exposed to hazardous levels of the chemical until the results are known.
Taken from the beginning of thesis.