Gas volume temperature relation
OverviewMeasurements can be done under different environmental circumstances, relating to air temperature and humidity. Depending on required outcome, conversions to e.g. BTPS or ATPS may be be necessary.
All conversion are processed internally based on the assumed measurement settings. The settings are chosen at the beginning of the analysis, see "Process the source file and calculate spirometric parameters".
Ambient temperature and pressure saturated (ATPS) settingThe gas conditions are ambient temperature, pressure, saturated with water vapor. The inhaled gas is assumed to have ambient temperature.
Ambient temperature and pressure (ATP) settingThe gas conditions are like under ATPS settings, but not saturated with water vapor. The inhaled and the exhaled gas is assumed to have ambient temperature.
ATP corrections are applied in Pulmochart during the calculation of the tidal volumes.
Body temperature and pressure saturated (BTPS) setting
Under this setting the lung volumes and flows are standardized to barometric pressure at sea level, body temperature, saturated with water vapor.
An overview of the different settings and their conversion is presented in [Quanjer].