As listed in Table S1 , currently available EBC collection devices, e.g., the Rtube and the EcoScreen, are comparable to ours with respect to rate of EBC collection. However, our EBC device has advantages in size, weight, and simplicity. In our study, we used a 16 cm long straw for exhaling toward to the super hydrophobic surface without any control of saliva for the possible contamination. However, our collection time was only 1-4 min, and during such short sampling period the sample contamination by saliva is very limited given the length of the straw. Another advantage of our developed device is the one time use of the hydrophobic parafilm (disposable) and exhalation straw with an easy collection of EBC, which thus prevents the possible cross contamination and facilitates the collection of EBC samples from a large number of subjects. This is particularly useful during an influenza outbreak or a man-made bio-terrorism attack in which a rapid screening of exposed persons needs to be conducted immediately.