Barcelona, Spain, 10 July 2026
More than half of the homes of high-risk patients with COPD or severe asthma contained at least one indoor air pollutant at potentially harmful levels, according to findings from the EU-funded K-HEALTHinAIR project, a research team led from the Hospital Clínic de Barcelona and the FRCB-IDIBAPS institute ran a two-year pilot in the Barcelona-Esquerra Integrated Health District. Researchers also demonstrated that combining home environmental monitoring with a nurse-led hybrid model of care offers a practical strategy to identify risks earlier and support proactive disease management. A total of 205 high-risk patients with COPD or with severe asthma were followed to test two complementary ideas at once: whether low cost sensors can reveal actionable household indoor pollution, and whether a “hybrid” model of care, digital tools plus in-person nursing, can keep patients well and out of hospital.
What the air at home revealed
Over a two-month window, low-cost sensors continuously tracked carbon dioxide, fine particulate matter and formaldehyde in participants' dwellings. Overall, more than half of the homes monitored (51.7%) had at least one pollutant in an at-risk range. Fine particulate matter was by far the main problem, with 40.1% of homes classified as at risk, and tobacco smoking, active or passive, emerged as its strongest driver: smokers were present in 85% of the most polluted dwellings. Formaldehyde, linked to furnishings and building materials, exceeded the safe threshold in around one in eight homes.
Crucially, the sensors proved reliable and easy to deploy for short, targeted screening, turning “invisible” indoor exposure into something a care team and a patient can see and act on, for example through smoking-cessation support, ventilation advice or source control.
“Measuring indoor air quality inside the patient's home changes the conversation. Instead of discussing environmental risks in general terms, we can identify concrete problems and work together on practical solutions. Making invisible exposures visible is often the first step towards lasting behavioural change.”— Alba Gómez-López, research nurse and PhD candidate, K-HEALTHinAIR / Hospital Clínic de Barcelona
Importantly, the pilot did not find a direct, immediate link between home air quality and past hospitalisations. The researchers stress that this was an exploratory analysis: exacerbation risk is multifactorial and unfolds over long timescales, so indoor exposure is best understood as one modifiable piece of a bigger clinical picture, not a single trigger.
A hybrid model that fits the patient
Alongside the air-quality work, the team refined a hybrid care intervention that pairs advanced digital support with hands-on care from a nurse case manager. It rests on three intertwined elements: an individual health-risk assessment, flexible digital tools, and personalised, nurse-led in-person care.
Two ingredients stood out. First, home-based, patient-administered oscillometry, a simple tidal breathing test, gave an objective read on lung function during flare-ups, moving beyond symptom reports alone. Second, the digital backbone was provided by the Health Circuit platform, which connects patient, nurse and reference physician through a shared, adaptive care plan and channels data such as symptom questionnaires and heart-rate variability from a wrist sensor.
“The old divide between the clinic and the home is what we need to dissolve. A well-designed hybrid model lets a nurse and a physician act on objective signals, oscillometry, physiological data, home exposure, before a patient deteriorates. That is how we prevent avoidable admissions rather than simply reacting to them, and the digital layer, in our case Health Circuit S.L., is what makes it work at scale.”
— Dr Josep Roca, pulmonologist and emeritus researcher, Hospital Clínic de Barcelona / FRCB-IDIBAPS, and co-founder of Health Circuit S.L.
Building on an earlier trial in which a nurse-led integrated intervention cut unplanned hospitalisations by 40%, the Barcelona pilot focused on the harder question of real-world adoption: how to embed these tools in routine clinical workflows so they can be sustained and transferred to other sites, and, potentially, to other chronic conditions.
Together, these findings illustrate a shift from reactive to proactive respiratory care. Rather than waiting until patients become severely ill, healthcare teams can combine household indoor air monitoring, digital technologies and nurse-led clinical follow-up to identify early signs of deterioration and intervene before hospital care becomes necessary. The Barcelona pilot provides a practical blueprint for implementing this approach within routine healthcare systems.
More information about the K-HEALTHinAIR project, together with materials and resources developed as part of the project, is available at: www.k-healthinair.eu.