## 5 Conclusions and Perspectives  
The limited published literature with detailed IAQ and airflow measurements in low-energy occupied buildings was highlighted during the IEA-EBC Annex68 \"Indoor air quality design and control in low-energy residential buildings\" project, which prompted us to conduct these measurement campaigns. We carried out an inter-comparison study of several types of devices (low-cost, laboratory devices, intermediate devices) for validation and/or correction of measurements. During our two campaigns, the measurement devices were set up in all of the rooms and outside the house recording measurements every 10 min. In some rooms, two or more types of devices measuring the same parameter, were used to ensure the precision of the measurements. Ventilation airflow at each supply and exhaust was measured. The survey completed regularly by occupants explained many of our queries. IAQ performance indicators related to pollutants (formaldehyde, particle numbers and PM2.5, RH, TVOC, and CO2) were reviewed and used. For long-term exposure we used the reference exposure limit value (ELV) set to the minimum value used throughout the world, i.e., 9 \(\upmu\text{g}\cdot\text{m}^{-3}\) for formaldehyde (Office of Environmental Health Hazard Assessment [57]) and 10 \(\upmu\text{g}\cdot\text{m}^{-3}\) for PM2.5 [58]. Thus, for formaldehyde and PM we compared the calculated cumulative exposures to the threshold exposure corresponding to a constant threshold concentration. These measurements confirm previous results from several studies: cooking, grilling, and toasting are the activities that emit the most particles. Our results highlighted several other interesting issues. First, the relevance of the selected IAQ performance indicators related to the conclusion on the IAQ. Indeed, we showed that the conclusions on IAQ differ depending on whether we look at the concentrations or at the cumulative exposure. The latter one is \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \begin{tabular}{c} **Maximal CO2** \\ **E\({}_{\text{1000 ppm}}\cdot\text{h}\)** \\ \end{tabular} & \begin{tabular}{c} **Maximal Time-Spent** \\ **with RH Out of 30–70\%** \\ \end{tabular} & \begin{tabular}{c} **Maximal Time-Spent** \\ **with RH > 70\%** \\ \end{tabular} & \
\begin{tabular}{c} **PM2.5** **E\({}_{\text{max}}\)** \\ **\(\upmu\text{g}\cdot\text{m}^{-3}\cdot\text{h}\)** \\ \end{tabular} &
\begin{tabular}{c} **Formal-dehyde** \\ **E\({}_{\text{max}}\)\(\upmu\text{g}\cdot\text{m}^{-3}\cdot\text{h}\)** \\ \end{tabular} \\ \hline C1 & \(2.45\times 10^{5}\) & 44 & 1.2 & 728 & 363 \\ \hline C2 & \(1.6\times 10^{5}\) & 14 & 2.42 & 936 & 321 \\ \hline Relative gap (\%) & \(-35\%\) & \(-68\%\) & 102\% & 29\% & \(-11\%\) \\ \hline Threshold & \(1.68\times 10^{5}\) & 30.78 & 38.48 & 1680 & 1512 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: IAQ performance indicators. more precise because it takes into account the concentrations only where and when the occupants are present. Nevertheless, this indicator is rarely calculated as we lack detailed measurements with spatial and temporal discretization. Second, we showed that such detailed measurement campaigns improve our knowledge on the transport of pollutants between rooms, which cannot be assessed with common IAQ studies including only two measurements points and passive measurements over 1 week. Here, the transfer of pollutants was clearly observed between rooms. The kitchen was mostly the main source of producing PM\({}_{2.5}\) and from there it spread variably to the other rooms depending on the speed of the ventilation system, its position, and/or opening and closing the doors. The same is true for TVOC which is diffused from kitchen to BR1 as was observed on 7 and 8 April, the time of preparing meals with a high speed of ventilation and opening doors at the same time. Finally, even if these are preliminary results at this stage, we observed that occupancy periods were correlated with higher pollutant concentrations, at least for TVOC and formaldehyde.