Propane-oxygen torches attain fairly high temperatures, yet the fact that oxygen is used rather than air for combustion would normally lead one to believe that NOx would not be emitted at high levels. Part of my job involves performing air sampling and analysis to measure employee exposure to chemicals and irritants. Detector tubes are a fairly inexpensive means to obtain quick, reasonably reliable measures of many substances. Using a small, hand-operated pump, air is pulled through a tube, which is coated with a material that reacts with the substance of interest. A colored stain is formed that is proportional to the amount of the substance present in air.
Different tubes are available for many substances.
While Pamela made beads, I used detector tubes to measure the levels of carbon monoxide, carbon dioxide, and NOx in the room. Carbon monoxide was not detected under any condition. Carbon dioxide, while elevated a bit from ambient levels, was not at levels that would cause concern. Pamela's current studio is our spare bedroom, which has a single door and window. I have experimented with a variety of fan placements, and so far, I have not found a combination that effectively eliminates the NOx.