Fig. 2
From: Validity of a portable spirometer in the communities of China
Correlation plots between the values obtained from the two spirometers, for the spirometric parameters considered in this research. FEV1 forced expiratory volume in one second; FVC forced vital capacity; MMEF maximum mid-expiratory flow; PEF peak expiratory flow; FEF25 forced expiratory flow after 25% of FVC has been exhaled; FEF50 forced expiratory flow after 50% of FVC has been exhaled; FEF75 forced expiratory flow after 75% of FVC has been exhaled. Note * = measured by the portable spirometer; ** = measured by the conventional spirometer