## 3 Results
### IAQ Performance Indicators
#### 3.2.3 Particles Concentration  
Figure 6 presents the particle number outdoors and in the kitchen during C1 and C2. The outdoor concentrations for both campaigns displayed disturbances where one device stopped recording for three days during C1 as shown in Figure 6c. During C2, the outdoor peaked at midday and then were their lowest at midnight. Only on 7 April outdoor particle counts were higher at night than in the morning. The increases in concentrations were  
Figure 5: Percentage of time outside the range of 30–70% (health risk). \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & **BR1** & **BR2** & **BR3** & **BR4** & **Kitchen** & **Living Room** & **Bath 2** \\ \hline Cumulative excess exposure & & & & & & & \\
1000 ppm C1 (ppm-h) & 2.49 \(\times\) 10\({}^{5}\) & 1.77 \(\times\) 10\({}^{5}\) & 1.86 \(\times\) 10\({}^{5}\) & 2 \(\times\) 10\({}^{5}\) & 1.78 \(\times\) 10\({}^{5}\) & 1.76 \(\times\) 10\({}^{5}\) & 2.33 \(\times\) 10\({}^{5}\) \\ \hline ICONE air stuffiness index—C1 & 1.57 & 0.11 & 0.03 & 0.46 & 0.04 & 0.22 & 0.12 \\ \hline Cumulative excess exposure 1000 & & & & & & & \\ ppm C2 (ppm-h) & 1.36 \(\times\) 10\({}^{5}\) & 1.06 \(\times\) 10\({}^{5}\) & 1.02 \(\times\) 10\({}^{5}\) & 1.6 \(\times\) 10\({}^{5}\) & 1.01 \(\times\) 10\({}^{5}\) & 1.15 \(\times\) 10\({}^{5}\) \\ \hline ICONE air stuffiness index—C2 & 1.06 & 0.02 & 0.00 & 0.25 & 0.00 & 0.00 & 0.13 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Cumulative excess exposure to 1000 ppm and ICONE air stuffiness index for C1 and C2. found in the kitchen and mainly attributed to fine particles, i.e., particles having diameters less than 1 \(\upmu\)m, for which concentrations as high as 4.4 \(\times\) 10\({}^{5}\) and 8 \(\times\) 10\({}^{5}\) number. L\({}^{-1}\) were recorded during C1 and C2, respectively. The increases in indoor concentrations were sometimes correlated with increases in outdoor concentrations. This is particularly evident during the increase in concentrations during C1, which was recorded on February 9 at 20:00 for about two hours. At this time, we observe a peak outdoor concentration, followed by a peak in the kitchen outside of a cooking period (no cooking). The indoor peak is approximately 37% lower than the outdoor concentration. These results demonstrate that there can be a link between indoor and outdoor PM concentrations. The concentration increases in the kitchen can be clearly attributed to indoor activities such as cooking (frying, grilling, etc.) and no cooking activities. The increase in concentrations during C2 on 7 April was attributed to cooking activities (burned meal and frying). In the same way, cooking pancakes on February 9 at 16:00 was correlated with high particle numbers of approximately 3 \(\times\) 10\({}^{5}\) number. L\({}^{-1}\). For the two campaigns, PM\({}_{2.5}\) in the living room, kitchen, BR1, and BR2 were calculated and are reported in Figure 7. The average PM\({}_{2.5}\) are within the range of 3.8-6.7 \(\upmu\)g\(\cdot\)m\({}^{-3}\) and 3.9-7.7 \(\upmu\)g\(\cdot\)m\({}^{-3}\) with median ranges of 3.0-4.0 \(\upmu\)g\(\cdot\)m\({}^{-3}\) and 3.0-3.3 \(\upmu\)g\(\cdot\)m\({}^{-3}\) for C1 and C2, respectively. Figure 8 shows the PM\({}_{2.5}\) in the kitchen, BR1, and BR2. On February 9, the same events that caused spikes in particle numbers in the kitchen were also observed for PM\({}_{2.5}\) in the kitchen and bedrooms. The peaks during C2 were also attributed to analyzing the occupant survey. The occupants wrote that they opened fully all the windows and the doors. Figure 6: Particle numbers in: (**a**) kitchen during C1; (**b**) kitchen during C2; (**c**) outdoor during C1; and (**d**) outdoor during C2. The PM\({}_{2.5}\) in BR1 and in BR2 were lower than in the kitchen; they occasionally exceeded the ELV, but only for 50 min. Two peaks of 44 \(\mathrm{\SIUnitSymbolMicro m^{-3}}\) and 46 \(\mathrm{\SIUnitSymbolMicro m^{-3}}\) were measured during C2 in BR1.