New and Improved Procedures for Gas Sampling and Analysis in the National Air Sampling Network |
| |
| Authors: | G B Morgan C Golden E C Tabor |
| |
| Institution: | U. S. Department of Health, Education, and Welfare , Air Quality and Emission Data Branch, National Center for Air Pollution Control, Public Health Service , Cincinnati , Ohio , USA |
| |
| Abstract: | The NASN sampler for the collection of gaseous pollutants has been modified to increase its versatility and efficiency. Oxides of nitrogen are collected in bubblers employing a 70-100 μ frit with a collection efficiency of approximately 50% depending upon the frit porosity. Included in the sampler is a bubbler for the collection of aldehydes in which the aldehyde-MBTH complex is stable at least two weeks. This inert bubbler, which is constructed of polypropylene and Teflon, makes it possible for samples to be collected over the network and analyzed at a central laboratory. In addition, gaseous ammonia is collected in 0.1N H2SO4. This collecting system has an efficiency of greater than 85%. Low-level samples are analyzed automatically employing Nesslerization, whereas high-level samples from source emissions may be collected in indicating boric acid and titrated with 0.02N H2SO4. The sampler will accommodate either 50 or 100 ml polypropylene collecting tubes. |
| |
| Keywords: | |
|
|
