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

Abstract
It was planned to install 305 m (1000 ft) of tubing on a television tower to transport ambient air samples from different height levels to pollutant monitoring instruments at ground level. A feasibility study was undertaken to determine the sorption characteristics of sulfur dioxide and carbon monoxide on various conduit materials. Sorption studies were completed on 30.5 m (100 ft) lengths of 1.3 cm (Y2 in) diam tubings of glass, Teflon, tygon, polypropylene, PVC piping, aluminum, and stainless steel. Final tests were completed on 305 m of 1.9 cm (3/4 in) diam stainless steel tubing. The following variables were investigated: tubing diameter, gas concentration, flowrate through the tubing, temperature, humidity, and the effect of sorption with sulfur dioxide and carbon monoxide alone or together. The parameter ranges studied approximated either atmospheric or air sampling conditions. For carbon monoxide, there was no significant difference between the mean inlet and outlet tubing concentrations under the conditions of the study. With sulfur dioxide, there was neither tubing adsorption nor desorption under the experimental parameters studied, except for tygon, PVC, and aluminum. After a conditioning period with sulfur dioxide, tygon, PVC, and aluminum could also be used as air inlet conduits; tygon is not recommended.