FIG. 1.

Numbers of released particles per sample of each type of material as measured by the OPC. (A) MEA; (B) ceiling tile; (C) gypsum board. The bars indicate geometric means, and the error bars indicate the geometric standard deviations of three trials. Dotted lines indicate that there is no significant difference between geometric means; solid lines indicate that the geometric means are significantly different. Asterisks indicate the level of statistical significance (one asterisk, P < 0.05; two asterisks, P < 0.01; three asterisks, P < 0.001).