When citizen science meets radon building diagnosis: Synthesis of a French pilot project developed in the framework of the European RadoNorm research project.

As part of the European RadoNorm research project, citizen science pilot projects focusing on the management of radon risk in houses have been implemented in four countries. This article describes the methodological basis, the development and the results of the French pilot project. Building on an initial review of existing literature, the pilot project aims to frame a 'participatory approach' aligned with the standards and recognized practices of citizen science. Particular attention was given to the management of data and the inclusion of ethical considerations. The focal point of the project was the process of radon building diagnosis which is supposed to be carried out whenever (high) radon concentrations are measured and should be prerequisite to mitigation works. As experience shows, however, this diagnosis is hardly implemented in France. To help remedy this situation, the pilot project recruited citizens already aware about radon from Pays Vesoul Val-de-Saône (East of France) to test an existing online self-evaluation guide for radon diagnosis, report on their operational experience and meet with radon/building experts. This enabled citizens to contribute to improvements in form and content to the guide and to ensure that it would be better fit for purpose. Comparison of the guide with experts' practices offered additional perspectives on what building diagnosis should entail. The pilot project produced rich and high-quality data that will nurture the evolution of the guide. The project demonstrated both the viability and the utility of applying the citizen science approach to radon post-measurement phases, with measurable benefits in bridging knowledge gaps and in encouraging behavioural changes. The results of using a citizen science approach in the field of radon management and research are encouraging, and they far outweigh the challenges involved in the implementation.

Fungal Contaminants in Energy Efficient Dwellings: Impact of Ventilation Type and Level of Urbanization.

The presence of growing fungi in the indoor environment has been associated with the development of respiratory problems such as asthma or allergic rhinitis, as well as the worsening of respiratory pathologies. Their proliferation indoors could be a result of water leakage or inadequate ventilation. Although the factors promoting mould growth have been widely investigated in traditional dwellings, little work has been done in energy efficient dwellings. Here, the effectiveness of ventilation type, i.e., natural or mechanical, in influencing mould development was estimated in 44 recent and 105 retrofitted energy efficient dwellings. Fungi growing on surfaces were investigated in the dwellings situated in rural, peri-urban, and urban regions of Switzerland. The presence of these fungi was also investigated in bedroom settled dust. Information on building characteristics and owners' lifestyle were collected. Significant associations were found with the level of urbanisation, the location of mouldy area in dwellings, and the diversity of fungal taxa. Dwellings in peri-urban zones showed the most frequent fungal contamination in the owners' bedroom and the highest diversity of fungal genera among dwellings. While the urbanisation level or the ventilation type favoured no specific genus, we found marked disparities in the diversity of fungi growing on surfaces in naturally ventilated versus mechanically ventilated dwellings. Aspergillus, in particular, was a frequent surface contaminant in bedrooms with natural ventilation, but not in those mechanically ventilated. We observed a strong association between fungal growth on surfaces and the number of fungal particles counted in the settled dust of owners' bedrooms. These results demonstrate the importance of ventilation systems in energy efficient dwellings in controlling fungal proliferation in living areas.

Volatile organic compounds in 169 energy-efficient dwellings in Switzerland.

Exposure to elevated levels of certain volatile organic compounds (VOCs) in households has been linked to deleterious health effects. This study presents the first large-scale investigation of VOC levels in 169 energy-efficient dwellings in Switzerland. Through a combination of physical measurements and questionnaire surveys, we investigated the influence of diverse building characteristics on indoor VOCs. Among 74 detected compounds, carbonyls, alkanes, and alkenes were the most abundant. Median concentration levels of formaldehyde (14 µg/m3 ), TVOC (212 µg/m3 ), benzene (<0.1 µg/m3 ), and toluene (22 µg/m3 ) were below the upper exposure limits. Nonetheless, 90% and 50% of dwellings exceeded the chronic exposure limits for formaldehyde (9 µg/m3 ) and TVOC (200 µg/m3 ), respectively. There was a strong positive correlation among VOCs that likely originated from common sources. Dwellings built between 1950s and 1990s, and especially, those with attached garages had higher TVOC concentrations. Interior thermal retrofit of dwellings and absence of mechanical ventilation system were associated with elevated levels of formaldehyde, aromatics, and alkanes. Overall, energy-renovated homes had higher levels of certain VOCs compared with newly built homes. The results suggest that energy efficiency measures in dwellings should be accompanied by actions to mitigate VOC exposures as to avoid adverse health outcomes.