|I commend authors for such thorough and detailed revision that has addressed all my concerns. I recommend the manuscript for publication after few technical corrections, listed below, are maid:|
Title: I do not think that ‘interannual increase’ is a correct term, ‘interannual variation’, maybe? Or, since you did provide a better proof for the trend, you could refer to an increase in secondary aerosol fraction due to potential growth in atmospheric oxidation potential, just a suggestion.
Reply to comment No 4: 'In Zurich, for instance, f44 during summer afternoons, when photochemical processes are most vigorous as indicated by high oxidant – OX (O3 + NO2), was found similar or lower than f44 on days with low -OX, while f43 (less oxidized fragment) tended to increase (Canonaco et al., 2015). The SOA is often divided into two factors: less-oxidized oxygenated OA (LO-OOA) and more-oxidized oxygenated OA (MO-OOA).'
Is this really correct – f44 lower for days with higher oxidation? Or this is a mistake, and the opposite was meant?
Reply to comment No 7: 'There are evident differences in meteorological variables from one period to the other (Fig. S7). In summer A, temperature (24.4º C) and solar radiation (259 W) are lower and average relative humidity (71%) and wind speed (2.0 m/s) are higher than in period B (27.0º C, 280W, 70.0%,1.7%), indicating a probably rainier or cloudier summer in period A.'
Check units for B, I assume, 1.7 is m/s? Also, are such differences in RH (70 and 71%) as well as WS (2 vs 1.7 m/s) significant? Otherwise, just state that they were similar.
Reply to comment No 7: 'The composition-dependent collection efficiency (CE) (Middlebrook et al., 2012) correction was applied (minimum, maximum) for Period A and B respectively: (0.45±0.68), (0.50, 0.99), exceeding CE=0.6 a 0.13% and a 1.5% of data).'
Is period B data missing here? I see the average, SD and range for the A period only?