DOI: 10.5281/zenodo.15462759
title: Labelled indoor activity detection via gas sensor data (MOX sensors, commercially available)

description: This dataset is briefly described on section 2.3 of Miranda et al. (2024), DOI: 10.1016/j.indenv.2024.100026 and it was developed during the progression of the first author's thesis. It contains data collected between November 2022 and March 2023, by two volunteers who performed daily activities in a 13 m2 (46 m3) room. The emissions resulting from the daily activities were monitored by 21 unique commercially available MOX gas sensors arranged in four different sensing modules (Table 1 from the paper), where module 1 is referred as PODs in the dataset, while module 2 is IMT_Thick, module 3 is IMT_Thin, and module 4 is mod1 and mod2. 

Modules 1 and 4 contain measurements of temperature (ºC) and relative humidity as well. Modules 1 also contain data from electrochemical sensors represented by "ec" and measurements for PM10 (ug/m³) represented by "p1" in their respective columns, during the experiments, however the ec's stopped working so they should be ignored. CO2 is also measured (in ppm) using module 1.

A fully processed dataset file is available as Synced_red.csv, where all the data is synced (sampling period of 10 seconds) and properly arranged. All modules are considered, and they are represented by their suffixes. The first column is the time with format "dd/mm/yyyy HH:MM:SS" in which the samples were collected (UTC+01:00, France). Measurements from MOX from all modules are made in resistance (ohms). TGS4161 (not MOX) is in volts.

A set of 10 activities was selected consisting of: (i) Static activity, where a volunteer remained in the environment seated in a chair with no other source of emission, reading or using a computer, for example, with a duration of 30 minutes; (ii) Oil frying an egg followed by its consumption, where a volunteer performed this using sunflower oil and an electric stove top, duration of 10 minutes; (iii) humid activity represented by the drying of a hand towel previously washed with dish soap, duration of 30 minutes; (iv) Vacuum cleaning the environment using a battery operated hand vacuum cleaner, duration 10 minutes; (v) Floor cleaning using a custom solution of 4 L of water to 50 mL of detergent and 10 mL of bleach where the volunteer covered the floor completely using a mop flowed by the drying using a dry mop, duration 15 minutes; (vi) Low intensity exercise, where the volunteer was instructed to perform any type of physical activity that barely break a sweat during 15 minutes, examples of these activities were stretching and yoga; (vii) the Use of scented candles where it remained lit for 15 minutes and then another 15 minutes where it was off, before aerating the room, the same scented candle was used during the whole experiment; (viii) Aeration of the room, where the large window was left wide open 10 minutes; (ix) Do-it-yourself (DIY) activities using hot glue where the volunteer was instructed to glue different pieces of wood and paper together during 15 minutes; and (x) Hand sawing or drilling pieces of wood for 10 minutes. While activities were assigned a suggested duration, some variation within acceptable limits (one to two minutes) were permitted to replicate real-world scenarios. 

Last column of "Synced_res.csv "contains the activity labels according to tags in the order presented here and in tab "Activities" from "activites.xlsx" (label 0 represents no activity), where a journal of activities can also be found in tab "Done so far" as well.