Fig. 3.

Data reduction steps. A total of 2,392 features were detected in at least one of the 20 macaque breath samples analyzed. Features were reduced by the removal of artifacts (e.g., siloxanes and phthalates), the removal of features not statistically different between breath and room air (P < 0.05), the removal of sparsely present features (not present in 100% of preinfection samples or 100% of postinfection samples), and by selection of discriminatory features through random forest classification.