The decreased expression of CD11b could be caused by the attachment of monocytes with this adhesion marker to the endothelium. Our results on CD11b expression are consistent with the results from a 2-hour inhalation exposure of healthy subjects to ultrafine carbon

particles, where the subjects had lower expression of adhesion molecules CD11b/CD18 on monocytes and CD11b/CD18 and CD49d on granulocytes (Frampton et al., 2006). By contrast, chronic biomass smoke exposure was associated with increased HSP inhibitor surface expression of CD11b/CD18 in circulating granulocytes and monocytes in women (Ray et al., 2006). A detailed assessment of the indoor source activities in the homes of the subjects in the present study showed that candle burning, cooking and toasting resulted in increased Sunitinib nmr PNC and were responsible on average for 51% of the residential integrated exposure (Bekö et al., 2013). Candle burning occurred in half of the homes where, on average, it was responsible for almost 60% of the integrated exposure (Bekö et al., 2013). Yet, the exposure assessed as total average PNC was very closely correlated with exposure assessed specifically in relation to candle burning, which also showed the same significant associations with lower lung function and with higher HbA1c and leukocyte counts.

Cooking contributed much less to event-related exposure and was not associated with any health outcome. This was the case, possibly because cooking events were of relatively short duration and they occurred in kitchens with fume hoods and

at a certain distance from the monitor placed in the living room. Accordingly, exposure to emissions from candles and possibly similar indoor sources might contribute to decreased lung function and inflammatory activation of leukocytes. Candle burning also emits nitrogen dioxide, which could contribute to the association related to lower lung function. The lack of association between lung function and whether or not candles are used in the homes of the participants in general suggests that if the association with the candle burning source events is causal, it would be a short-term effect of high level exposure. Glycogen branching enzyme Moreover, individuals with asthma could well be more susceptible, in line with decrements in lung function related to traffic related PNC (McCreanor et al., 2007 and Strak et al., 2012). A limitation of our exposure assessment is that we did not analyze the composition of indoor and outdoor PM, which might have helped explaining the different associations with the health outcomes we observed in our study population. However, indoor and outdoor PNC were inversely correlated, whereas the indoor particle mean diameter was correlated with outdoor particle mean diameter and PM mass. This might have suggested that only larger particles from ambient air contributed to indoor levels, but this was not reflected in correlations between indoor and outdoor PM2.5.