Peak nasal inspiratory flow rate (PNIF) PNIF will be measured using the method described in the package insert for In-Check Nasal Inspiratory Flow Meter (Clement Clarke, Harlow, England Issue 2, 05/2000). The subject will exhale fully, hold the device horizontally, ensure the face mask forms an air tight seal around the nose, and inhale forcibly through the nose. This maneuver should be a short, sharp inspiratory action of about one-second duration. The test will be repeated 3 times and the highest result recorded. The clinical research unit staff will observe for possible obstruction called the nasal valve. This can occur during inspiration when the nostril(s) close and obstruct further inspiration. The test will be repeated if this occurs.