Nested Factorial Design for Analysis of Cigarette Tar

To study the differences of various variation sources in the determination of tar content in cigarette smoke, nested variance analysis and nested factorial design analysis were applied. The results showed that: 1) Of all the definite variation sources, total particulate matter had the greatest variation of 42.0%, followed by moisture content in total particulate matter and Cambridge filter (W&W), and that in blank filter, their variation was 30.6% and 25.3%, respectively; the variation introduced by nicotine and gas chromatography was only 2.3%. Therefore, the first three variation sources were of importance for reducing measurement variation. 2) The variation induced by time was 42.9%. So it is a factor should be taken into account in design of comparison test of cigarette's tar content.