2.7. Measurements
The patients wore the personal monitors for 24 h to continuously measure exposure to particulate matter PM2.5, with continuous geolocalisation monitoring (AirSpeck) and a RESpeck monitor to measure the breathing rate (Br), to detect activity and any acute changes in breathing before and during exposure to SHS. To have a standardised period for the measurement of breathing rates, we selected a period of 7 min when the patient was at rest before the exposure to SHS, as defined by the RESpeck measurements, and the PM2.5 was less than 10 µg/mAt the second study centre visit on the day post-exposure, all data recorded by the devices were downloaded and checked, and any diary card anomalies were addressed and clarified with the patient.Routine pulmonary function tests consisting of forced expiratory volume in the first second (FEV