Abstract
Currently available compilations of methods of air analysis are listed. Collaborative testing is urgently needed to reconcile differences and to demonstrate the accuracy of these methods. The Analytical Methods Evaluation Service of the National Center for Air Pollution Control conducted a survey of the instruments and manual methods of analysis in use. Responses are tabulated from about 80 laboratories, in 28 states and 3 foreign countries. Sulfur dioxide was the most widely measured pollutant. The first collaborative study organized by the Analytical Methods Evaluation Service is described. The purpose was to evaluate the permeation tube technique as a primary standard method for generating known sulfur dioxide concentrations for instrument calibration and methods testing. Although a good beginning has been made, the testing of methods for measuring air pollutants has barely begun.