Each represents an hour (60 minutes) from January 14th to December 2nd 2020 inclusive (6901 hours in total). By pressing the "Increased PM2.5" button, the hours with good air quality will be separated from the ones with fair to poor air quality according to the Air Quality Index (AQI) developed by the manufacturer of the portable sensor we used. This index is compiled taking WHO’s safe thresholds into consideration, as well as the results of the sensor’s measurements. The graph shall be adjusted accordingly be pressing the "Increased PM10" button.