SYMPOSIA PAPER Published: 01 January 1976
STP32356S

Qualification of Source Test Methods as Reference Methods

Source

Air pollution measurements require test methods that have a demonstrated capability to yield reliable data when the procedures are carried out by people with different backgrounds and experience. Collaborative testing can provide “real world” situations in which the performance of test methods can be evaluated and useful measures of the accuracy and precision of data obtained by a given method can be obtained. For methods designed to measure emissions from stationary sources, this form of round robin approach requires that the samples be collected on-site and simultaneously by the various teams involved. Laboratory analyses of the samples can then be performed on an individual basis. Statistical analysis of the collaborative test data from properly designed experiments should yield estimates of within-laboratory and between-laboratory precision and accuracy of the method under test. It should also be possible in some cases to separate the overall accuracy and precision into the individual components due to sampling techniques and laboratory analytical procedures.

This discussion is concerned with measurement methods for gaseous emissions from stationary sources. The circumstances and data cited are based on experience with the American Society for Testing and Materials Project Threshold test program. Collaborative testing of methods for sulfur oxides and nitrogen oxides is discussed specifically; however, the considerations involved with the experimental design, conduct of the testing, and data analysis are applicable to testing of other methods. Collaborative sampling was performed at both an oil- and coal-fired power station, a foundry, a cement plant, and using a pilot-plant furnace unit with gas and oil firing. Samples which were spiked with known amounts of the pollutant gases were included at the pilot plant site to provide a measure of the accuracy of the methods.

Sampling for sulfur oxides was accomplished by a continuous method in which the sulfur trioxide was condensed from the gas stream and the sulfur dioxide was absorbed and reacted with a hydrogen peroxide solution. Both sulfur oxides were then determined by the barium chloranilate method. The nitrogen oxides were samples by a “grab” technique in which an evacuated bulb was used to collect the gas sample. The nitrogen oxides were reacted with acidified hydrogen peroxide in the bulb, and then determined by the phenol disulfonic acid method.

Statistical analysis of the collaborative test data provides equations which express the accuracy and precision of the methods as functions of the gas concentration. Accuracy and precision of the analytical procedures also were measured from analyses of standard reference materials by the participating laboratories.

Author Information

Howes, JE
Battelle-Columbus Laboratories, Columbus, Ohio
Pesut, RN
Battelle-Columbus Laboratories, Columbus, Ohio
Price: $25.00
Contact Sales
Related
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Details
Developed by Committee: D22
Pages: 80–95
DOI: 10.1520/STP32356S
ISBN-EB: 978-0-8031-4674-7
ISBN-13: 978-0-8031-0297-2