Democratize air quality

Make air quality data actionable for everyone

For HackZurich 2022, we invite you to create the links between available sensors and actuators that will be able to improve air quality for everyone. Watch the preview the teaser below to get a clearer picture of what you can expect at HackZurich!

Our Challenge

1. Overview

We are presenting air quality data for two large rooms within a business complex in the greater Zurich area. The data contains information about indoor and outdoor air quality acquired by Sensirion sensors over a period of 486 days (about 1 and a half years). In addition, meteorological outdoor data are provided for the same period.

The goal is to visualize the data and, in doing so, to help the building maintenance team to improve the indoor air quality and to reduce energy consumption. Algorithms could also be developed to automate the process of air quality improvement and energy reduction.

Do you see any patterns or correlations in the data provided? Could the building management/maintenance team change anything in terms of the building’s energy consumption and air quality for the next year or the coming winter? Do you find new ways of visualizing the data at hand?

2. Background and Domain Knowledge

2.1. Description of room A
This room is used as a canteen in a commercial building complex. Ventilation of the room only happens through a HVAC system. The windows in room A cannot be opened at any time. Time series sensor data (CO2, VOC, PM 2.5) representing indoor air quality are measured inside of room A. In addition, the volume flow and temperature of the ventilating air by the HVAC system is available. Meals are mainly consumed in room A and the catering service kindly provided the total number of meals per day served over lunch. 

•    Do you see any correlation between the average building temperature and the seasonal solar impact? 
•    Can you identify daily patterns relating to the function of room A as a canteen? 

2.2. HVAC system of room A

The HVAC system of room A mainly consists of two air flow channels. One for fresh air inlet from outside of the building into the canteen, one used as an outlet of the used air from the canteen towards outside of the building. 

•    The volume of fresh air flowing through the ventilation system into the canteen is measured as a function of time. 
•    Along the inlet are two main HVAC components: a heat exchange device and a heater.
•    3 temperature sensors measure the temperature of the fresh air flowing from outside into the building, after the heat exchange and before the building heater, as well as after the heater right at the fresh air inlet of the canteen. 

Heat exchange device:
•    Heat contained in the air flowing through inlet and outlet is exchanged in the heat exchange device. The goal is to use the energy of the air in the outlet for partially heating up the air flowing through the inlet during winter. During summer, the opposite mechanism helps to save energy. Hot air from outside is partially cooled by the air flowing through the outlet taking away part of its energy. 

•    This element is actively heating the fresh air flowing though the inlet from outside of the building and into the canteen. Temperatures are measured right before and after the heater. 

•    Used air is leaving the canteen through the outlet all the way to outside of the building. On the way out the used air is passing through the heat exchange device either passively heating or cooling the fresh air in the inlet channel. Temperatures are measured both before and after the exchanger as function of time.

2.3. Description of Room B
This room is located on the roof top terrace of the building. It is mainly used for venues and social events but also during lunchtime for eating. Note that the sliding windows of this room can be opened by anybody at any time. In general, this room can be considered as well ventilated. Sometimes people smoke or grill on the rooftop terrace in front of this room. 

•    Particulate matter (PM2.5) and nitrogen oxides are typical outdoor air contaminants. Nearby road traffic can lead to nitrogen oxide exhaust from car engines. Smoking can yield locally increased particulate matter concentrations. On the other hand, carbon dioxide and volatile organic compounds (VOC) are typical indoor contaminants. Carbon dioxide correlates well with human presence within a room. In general, the windows in this room have been frequently opened and closed (airing events) over time. 
•    Is there a specific event occurring on a weekly basis in Room B?

2.4. Description outdoor measurement data
The outdoor measurement device is located right in front of the building and sits close to a smoking area. All signals labeled as ‘estimated’ are sourced from a meteorological service provider for the building's location. 

3. Description of the data set
Time period: 486 days between 02.05.2021 and 31.08.2022

Sampling interval: 10 minutes i.e. 600 seconds

3.1. Time series sensor parameters
3.1.1. Outdoor meteo data for building location

•    visibility_outdoor_estimated: Estimated outdoor visibility in km
•    cloudcover_outdoor_estimated: Estimated outdoor cloud coverage in %
•    dewpoint_outdoor_estimated: Estimated outdoor dew point in °C
•    humidity_outdoor_estimated: Estimated outdoor humidity in %
•    humidity_outdoor_measured: Outdoor measurement of relative humidity in %
•    precipitation_outdoor_estimated: Estimated outdoor precipitation within last hour in mm/h
particulate matter
•    particulate_matter_outdoor_measured: Outdoor measurement of particulate matter (2.5μm) in μg/m3
•    pressure_outdoor_estimated: Estimated outdoor ambient pressure in mbar
•    temperature_outdoor: Outdoor measurement of temperature measured in °C
•    temperature_outdoor_estimated: Estimated outdoor temperature in °C
•    wind_dir_outdoor_estimated: Estimated outdoor wind direction in °
•    wind_gust_outdoor_estimated: Estimated outdoor wind gust in km/h
•    wind_speed_outdoor_estimated: Estimated outdoor wind speed in km/h
•    uv_outdoor_estimated: Estimated outdoor uv index in arbitrary units (from 1 to 11)

3.1.2. Data room A (Canteen)
measured indoor air quality
•    co2_room_A: CO2 concentration in room A in ppm
•    tvoc_room_A: Total volatile organic compounds concentration in Room B in ppb
•    particulate_matter_room_A: particulate matter concentration (2.5μm) in Room A in μg/m3
meta information
•    consumed_meals: Number of consumed meals served during lunch in room A
HVAC system of room A
•    temperature_ventilation_system_fresh_air_in: Temperature of outside air when entering heating system in °C
•    temperature_ventilation_system_fresh_air_intermediate: Air temperature between heat exchanger and heater in °C
•    temperature_ventilation_system_fresh_air_out: Temperature of air entering room A in °C
•    temperature_ventilation_system_used_air_in: Temperature of air exiting room A before entering heat exchange in °C
•    temperature_ventilation_system_used_air_out: Temperature of air exhaust after heat exchanger in °C
•    volume_flow_ventilation_system_in: Volume flow entering room A in m3/h

3.1.3. Data room B (Sky Bar)
Measured indoor air quality
•    co2_room_B: CO2 concentration in room B in ppm
•    tvoc_room_B: Total volatile organic compounds concentration in room B in ppb
•    no2_room_B: NO2 concentration in Room B in ppb
•    particulate_matter_room_B: particulate matter concentration (2.5μm) in room B in μg/m3
•    humidity_room_B: Humidity in room B in C
•    temperature_room_B: Temperature in room B in C


Hack Zurich 2022
22.4 MB
Workshop Challenge
8.2 MB

Need help?

Sensirion tech experts will be at the booth in person Friday and Saturday until 23:00-24:00, and Sunday until the end of the closing ceremony, at 16:00. We also offer remote help in the Discord Chat  #17-sensirion. Write us a message and we will reply as soon as possible!

Indoor Air Quality

The air we breathe is the basis of a healthy life: how to measure and improve it.


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Sensirion is an international high-tech company with its headquarters in Switzerland and subsidiaries in Asia, North America and Europe. For two decades, the ETH spin-off has been developing and producing world-leading sensors and sensor solutions for a wide range of applications in the medical technology, automotive and consumer goods sectors. As a market leader, Sensirion offers stability and security – and embodies a pioneering startup spirit. Today, around 1000 employees do their utmost with expertise and passion to stay one step ahead. The common goal: creating sustainable change with innovative sensor solutions. For greater health, efficiency, security and quality of life – for a smarter future across the whole world.

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