Identification of chemical and biological determinants, their sources, and strategies to promote healthier homes in Europe

Project Information

INQUIRE

Grant agreement ID: 101057499

DOI

10.3030/101057499

EC signature date 20 May 2022

Start date 1 September 2022

End date 31 August 2027

Funded under

• Health

Total cost

€ 7 844 543,75

EU contribution

€ 7 830 787,00

Coordinated by

STIFTELSEN NILU
Norway

Periodic Reporting for period 2 - INQUIRE (Identification of chemical and biological determinants, their sources, and strategies to promote healthier homes in Europe)

Reporting period: 2024-03-01 to 2025-08-31

Summary of the context and overall objectives of the project

INQUIRE aims to protect citizen health by providing knowledge, tools and actions that substantially improve indoor air quality (IAQ) in European homes. Our mission is to support innovation in policy, regulation and industry by generating and sharing new data and science-based evidence on indoor chemical and biological determinants beyond current IAQ guidelines. This contributes to the European Green Deal and the EU’s Zero Pollution Action Plan.
Air pollution is a major determinant of early death risk, causing more than 6 million premature deaths each year globally. While European outdoor air quality standards exist for many pollutants, indoor exposures may be more important for public health. People spend up to 90% of their time indoors, where the concentrations of many pollutants can exceed those outdoors. Yet, knowledge about the range of chemical and biological determinants indoors, their sources and their health risks remain limited. Regulators still lack a comprehensive list of hazardous indoor pollutants, hindering effective measures for healthy buildings.
Evidence shows that indoor environments contain far more and more complex chemical and biological determinants than those defined by WHO IAQ guidelines. Over 350,000 chemicals are registered in global commerce (>100,000 in the EU), many of which are relevant indoors, and new or poorly characterised chemicals enter Europe through imported products and materials. Everyday items—building materials, furniture, electronics, personal care products, cleaning products and toys—release synthetic chemicals indoors, leading to exposure and a wide range of health effects beyond cancer and mortality, including endocrine disruption. Interactions between chemicals and the indoor microbiome may further influence adverse health outcomes. Public concern is high: 84% of Europeans worry about chemical exposures in daily products. To safeguard public health, a better understanding of indoor pollutants, their sources, and effective strategies to reduce them is essential.
INQUIRE is in the process of generating robust, science-based evidence to characterise and prioritise hazardous chemical and biological determinants of household IAQ, along with their sources and exposure drivers. The project focuses on families with infants and young children (<5 years old), who spend substantial time indoors and are especially vulnerable to chemical and biological determinants. By focusing on home environments—the dominant indoor space for young children—INQUIRE aims to identify and evaluate innovative actions for citizens, and industry (product/material producers and constructions) to reduce harmful exposures via safer products, materials and mitigation strategies. The outputs will support a more comprehensive European approach to improving IAQ and healthier indoor environments.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

During this reporting period, INQUIRE shifted from its initial preparation phase into full data production. Baseline and seasonal sampling were completed in eight European countries, collecting indoor and building-adjacent air, household dust, consumer products and urine samples. These harmonised datasets now underpin the chemical, biological and toxicological work across the project.
Chemical screening of air and dust detected hundreds of volatile and semi-volatile compounds, many of which are not currently regulated. Differences in the chemical composition observed between countries and individual homes highlight the diversity of indoor environments and provide important information on key exposure drivers. Toxicological work advanced through biomonitoring of adults and children and large-scale toxicity testing of indoor air and dust extracts. Results show distinct toxicological profiles across countries and have helped to prioritise mixtures and samples most relevant for further tasks.
The project also launched the first real-world intervention studies in homes targeting both improved IAQ and reduced exposure to hazardous substances (VOC and SVOCs). Air purifier trials conducted in UK, and product replacement interventions implemented in Slovenia, provided early evidence of practical measures to reduce indoor chemical exposures. Computer-based modelling complemented these studies by predicting effects of intervention across varied housing scenarios.
Significant progress was made in preparing INQUIRE’s data for future sharing. The Collaboration Agreement was finalised, the updated Data Management Plan delivered and ingestion of initial datasets into the internal data platform began. Communication and stakeholder engagement continued via the website, social media channels, conference participation and collaboration within the IDEAL cluster. The first periodic report was approved with minor comments, and coordination across the consortium remained strong.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

INQUIRE is producing results that substantially advance IAQ knowledge. Harmonised, multi-country sampling reveals chemical mixtures in homes that are far more complex than reflected in existing indoor guidelines. Detection of many previously unmonitored or unregulated chemicals highlights the need for broader approaches to IAQ assessment.
The project’s integrated approach combining non-target chemical screening, toxicological testing and consumer-products analysis enables a realistic understanding of combined exposures. It allows identification of emerging contaminants such as PFAS, plastic additives and other chemicals of concern, and direct links to their household sources. Early findings from the real-world intervention studies further move beyond the state of the art by providing rare experimental evidence on what can effectively reduce indoor pollutants in everyday living environments. Computer-based modelling strengthens these insights by exploring the potential impact of interventions across diverse European homes.
Together, these outputs provide new scientific evidence, new assessment tools and new real-world insights that significantly extend the knowledge base on indoor environments and their health implications.

Overall concept of INQUIRE work plan