Sensors & Air Quality
electronic nose, air quality, CO2, sensors, asthma, wearable, indoor air quality, Nepal, schools, Jordi Fonollosa, UPC, bioengineering
| Funding | Ministerio de Ciencia e Innovación (AEI) · UPC Social Commitment |
| Status | Active (multiple ongoing lines) |
| B2SLab PI | Jordi Fonollosa |
Overview
Air quality shapes health in ways that are often invisible — both literally, because most pollutants cannot be seen, and analytically, because the tools required to measure personal exposure have historically been expensive, bulky, and impractical for real-world deployment.
B2SLab’s sensor programme addresses this gap through a decade-long research effort covering four distinct but connected areas: electronic noses for chemical sensing and food quality; CO₂ monitoring in occupied indoor spaces; wearable personal exposure monitors for vulnerable patient groups; and biomass combustion and indoor air quality in low-resource settings. The programme develops sensor hardware, signal processing algorithms, machine learning models, and the deployment strategies needed to make these technologies work in demanding real environments.
This sensor expertise also directly underpins B2SLab’s contribution to the SERVICO2 project, where the group is responsible for the multi-sensor nodes deployed at headwater catchment sites across Europe to monitor greenhouse gas fluxes.
CO₂ monitoring in school environments
The placement problem
CO₂ concentration is the most widely used proxy for indoor air quality and ventilation adequacy in occupied spaces. During and after the COVID-19 pandemic, thousands of schools in Catalonia and Spain installed CO₂ monitors to guide ventilation decisions. The implicit assumption was that a single sensor per classroom could reliably characterise the air quality of the whole room.
It cannot.
These results have direct practical implications for school ventilation policies across Catalonia, Spain, and Europe — most of which currently offer no guidance on sensor placement.
Wearable air quality monitors for asthma patients
Personal exposure, not building-level averages
Population-level air quality monitoring — regulatory stations, school CO₂ sensors, building ventilation alarms — characterises the environment but not the individual. A child with asthma does not experience the average air quality of their municipality; they experience the specific pollutant concentrations in the spaces where they spend their time, in the specific temporal sequence in which they encounter them.
Wearable personal exposure monitors address this by continuously measuring what the individual actually breathes — enabling, for the first time, direct linkage between a patient’s pollutant exposure trajectory and their respiratory symptom diary.
This work supports the development of closed-loop sensor tools that can identify a patient’s high-exposure contexts and help clinicians tailor advice — not based on where the patient lives, but on what they actually breathe.
Electronic noses: chemical sensing and signal processing
Gas sensor arrays for complex mixtures
An electronic nose (e-nose) is an array of non-specific gas sensors whose combined response pattern encodes information about the chemical composition of a gas sample. Unlike a mass spectrometer, an e-nose cannot directly identify individual compounds; its power lies in pattern recognition — distinguishing complex gas mixtures, tracking changes over time, and classifying samples without requiring identification of every constituent.
B2SLab has developed signal processing and machine learning methods for e-nose systems across a range of application domains:
A persistent challenge in e-nose systems is instrument variability: sensors drift over time, and calibration models trained on one instrument degrade when applied to another. B2SLab has developed multivariate preprocessing and calibration transfer methods for MCC-IMS (Multicapillary Column Ion Mobility Spectrometry) based e-nose systems that substantially reduce this degradation.
Published: Sensors, 2025.
Nepal indoor air quality: biomass combustion and global health
Indoor air pollution as a neglected health burden
In high-income countries, indoor air quality concerns centre on NO₂, PM₂.₅, and VOC from traffic, cooking, and building materials. In much of the world, the dominant indoor air quality hazard is biomass combustion — the use of wood, dung, or agricultural residues for cooking and heating in poorly ventilated homes. The resulting indoor PM concentrations can be orders of magnitude above WHO guidelines, and the health consequences — respiratory disease, cardiovascular disease, adverse birth outcomes — disproportionately affect women and young children who spend the most time near cooking fires.
This work exemplifies the reach of sensor methodology when it is deployed in service of global health challenges rather than solely in high-resource research settings.
Connection to SERVICO2
The sensor expertise developed across these four research lines now forms the technical backbone of B2SLab’s contribution to SERVICO2 — a European Water4All project investigating greenhouse gas regulation in headwater catchments.
For SERVICO2, the group is designing, building, and deploying multi-sensor monitoring nodes capable of measuring CO₂, CH₄, N₂O, temperature, humidity, and VOCs in outdoor riparian environments — requiring all of the competencies developed in the indoor and wearable sensor lines: gas sensor selection, baseline drift correction, cross-sensitivity compensation, multivariate calibration, and rugged low-power hardware design for remote deployment.