|In this paper, the authors investigate the mass scattering and absorption efficiencies (MSE and MAE) of different aerosol particles sources at urban (BCN), regional (MSY) and remote (MSA) backgrounds in the Northwestern Mediterranean using PM10 chemical speciation and particles optical properties. The authors propose a new approach aiming to apportion the PM10 source contributions, identified by means of the Positive Matrix Factorization (PMF), to the measured particle sp and ap coefficients. This approach has the advantage that the computed MSE and MAE take into account the internal mixing of atmospheric particles. The paper is interesting for ACP, and the introduction, methodology, discussion and results are well documented, but requires corrections.|
-The authors use acronyms in text that are not defined previously. As example: P.3 Line 20 (NWM), P.5 Line 10 (WMB), P.10 Line 10. Also, sometime the authors use in text the acronyms and sometimes the words of these acronyms. Please, check the text carefully.
-P.6, 2.2 Section. Please, include a Table containing sampling sites, measurement period, measured parameter, … there is confusion in text and it’s not easy to follow the measured variables in each measurement station, as well as the measurement period. As example: P.6, Line 4, measurement period from MSY. P.6, Line 13, measurement period at BCN, MSY and MSA from aerosol absorption coefficient. The same from gravimetric PM10 mass concentrations. P.6, Line 5: “sp measurements at BCN are not available”, but in Line 31: “Optical measurements were considered for the periods 2009-14 at BCN…”. Please, clarify.
-P.8 Line 10: Please, explain more clearly in text the equation term [source] and their units.
-P.8 Line 18: the influence of the inlet change (PM2.5 by PM10) may be important, and may affects the measured sp values and the regression models.
-P. 9 and followings. Results section. The authors show average concentrations, and so on, but they do not include standard deviations in values. As example: Line 21. Please, include standard deviations, or an indication of errors, in all values included in Results section and Tables.
-P.14, Section 3.3.1, Table 2. The scattering Angström exponents (SAE), are computed using the values in Table 2? Or are computed for each 3 MSE measurements, and value in Table 2 is the average (include standard deviations)? Also from SSA. What physical interpretation do the SAE negative values have?, and the high value 3.549 at MSA for aged organics? This last value is close to the Rayleigh scattering (=4).
-Figure 7. Maybe it's better to show the reconstruction only for the independent subset (January-December 2015), and no the period 2004-2014 were the data values are used to the reconstruction model.