Sampling was conducted in a non-smoking private single-family house in the municipality of Terrassa (Spain) during February-March 2016. There are 16 files of .txt format and 7 files of .csv format. The lightest file is 3KB and the heaviest 371KB. Counting all 23 files , there are 2,01MB. Files from the HAPEX device are those which start with 'HAPEX'. The following numbers correspond respectively to sensor ID_Day_Month_Year_Hour_Minute_Second of the sampling start. Files from the TZOA-R device are those which start with 'TZOA'. The following 4 digits correspond to the sensor ID. Files from the DustTrak device are those which end with 'dusttrak'. From 22 Feb to 25 Feb the number of the files' name corresponds to DayMonthYear (DDMMYY) and HourMinute (HHMM) of the sampling start. In contrast, from 29 Feb, the number of the files' name corresponds to DayMonthYear (DDMMYYYY) of the sampling start. Files from the EL-USB-CO devices are those which end with 'co'. From 22 Feb to 25 Feb the number of the files' name corresponds to DayMonthYear (DDMMYYYY) of the sampling start plus DayMonthYear (DDMMYYYY) of the sampling end. The numbers before 'co' correspond to the sensor ID (e.g. '1co'). In contrast, from 29 Feb, the number of the files' name corresponds to DayMonthYear (DDMMYYYY) of the sampling start only. File from the Q-Trak device is the one that ends with 'qtrak'. The number of the files' name corresponds to DayMonthYear (DDMMYYYY) of the sampling start. File from BGI concentrations is the one that start with 'BGI'. This is a database where the variable corresponding to the PM2.5 concentration is called 'PMconcentration' (reported in �g/m3).