Carbon Monoxide and Sulfur Dioxide Adsorption on— and Desorption from Glass, Plastic, and Metal Tubings

Sulfur Dioxide Adsorption and Desorption on Various Filter Media

“…Polyethylene and tygon cannot be recommended unless long transient periods can be tolerated. Wohlers, et al, 1 suggest an estimated conditioningtime of 15 hr at 0.2 ppm for tygon. Copper, obviously, would not be considered in any case.…”

“…Wohlers, et al 1 , give a brief review of the literature. Sufficient evidence has been reported to indicate that losses of sulfur dioxide do occur when the gas contacts materials ranging from plastic bags, to tygon and rubber tubing, to stainless steel cylinders.…”

“…Sufficient evidence has been reported to indicate that losses of sulfur dioxide do occur when the gas contacts materials ranging from plastic bags, to tygon and rubber tubing, to stainless steel cylinders. Wohlers, et al 1 , were concerned with the case of sampling ambient air through long (100 -1000 ft) sampling lines. Initial studies were done with 100 ft lengths of tubings of glass, Teflon, tygon, polypropylene, PVC piping, aluminum, and stainless steel.…”

“…Prior to the sorption studies with filter media some sorption measurements were made on tubing material similar to those used by Wohlers, et al 1 The purpose of these tests was to establish what conditioning periods may be required for short sampling lines such as would be used in the subsequent sorption runs with filtering media. Ten foot lengths of tubing were used; this length is typical of what might be encountered in fixed or mobile field sampling stations.…”

The Effect of Sample Humidity on the Response Characteristics of SO2and NOxAnalyzer Systems: Aircraft Plume Dispersion Studies

“…In the former case, it has been found that tubing made from various materials, as well as filters and filter holders which may be included in the sample line, can absorb appreciable amounts of SO2 on being exposed to sudden increases in concentration. 5 " 8 The effect seems to be humidity dependent, and is more severe at higher humidities, where the SO2 is possibly retained in a water film which forms on the surface of the sample line. Therefore, the SO2 analyzer system response characteristics are also expected to depend on the humidity of the air sample.…”