It is of interest that the second tent (ID 2 in Table 2) had less than half the average BC concentration, but 1.6 times higher average PM2.5 concentration and a 3.7 times lower BC/PM2.5 ratio than the first tent (ID 1 in Table 2), despite being the same stove and tent type (simple stove, traditional tent). This is likely due to different moisture contents of yak dung on those two days. As discussed before, residents left yak dung uncovered in the sun and the snow event during the night of March 19 could have resulted in higher moisture content of the dung on the following day (March 20). This may have led to increased smoldering combustion on March 20 compared to March 17, which would cause higher PM2.5 and organic carbon production, but less BC because of relatively less flaming (Christian et al., 2003; Smith, 1987). These results demonstrate the need for more investigation on the impact of dung moisture content on combustion efficiency, as well as the difficulty of reducing both BC and PM2.5 emissions per unit fuel used simultaneously.