The paper investigates the spatial distribution and temporal evolution of aerosols over the western Mediterranean using the 8.5-year data record of POLDER-3/PARASOL aerosol relevant parameters like AOD, AOD fine and coarse fractions, the ansgtroem exponent (AE), spherical and non-spherical fractions. On top of confirmation of known features (i.e. seasonality and geographical trends) the impact of NAO and AQ trends are also revealed. The paper is well written and constitutes a valuable, yet not unique in terms of new knowledge, contribution to know literature, also supplementing Formenti’s paper that focused on the evaluation of the data set. The following comments could be taken into account before publication to ACP.

L 68-78: A brief literature review and basic comparison of the respective conditions met in the eastern part of the Mediterranean basin would be useful to highlight the particularities of this work.

L 170-175: The AE exponent has been traditionally used in the past as a proxy for particle size. Now that we are having the fine and coarse mode do you see any difference in the patterns observed? Is there any added value deriving from both types of information to justify their combined use? (a correlation map of AE with AODf and AODc might be interesting in this aspect.

L 185-188: You may also wish to see Hansson et al., (2021) https://doi.org/10.3390/atmos12040445

L 215: If only common days are used in Figure 3, would there be any substantial change in the sub-regional comparison?

L 344: In Fig. 7 the y-scale does not allow for discriminating details in the time series. I would suggest an axis break so that the data populated lower part of the plots occupies more surface (like 60% or more).

 L 399: Have you investigated to what extend do the trends in Fig .9 (AODf) might relate, in excess to global brightening, also to the economic crisis and the respective cutting down of many anthropogenic activities in the region? Could the Barcelona case be used as a proxy to support this assumption and further delineate/decompose the trends? (see L 428-432)

This paper describes the spatiotemporal aerosol distribution over the Western Mediterranean (hereafter: WM), based on 8.5-year (2005-2013) POLDER-3/PARASOL aerosol data records. Namely, the total, fine, and coarse AOD at 865 nm, the Angström exponent (670/865 nm), and the spherical and non-spherical contribution of coarse mode AOD is explored. In addition, in order to further support the observed interannual variability of coarse mode AOD, the North Atlantic Oscillation trends have been investigated.  The novelty of this work is that the POLDER-3/PARASOL aerosol products is used to study the WM. Having said that, however, the paper mainly confirms already known AOD-relevant patterns in the region.

While the paper is well written and understandable, the authors should definitely revisit the manuscript, try to shorten sections that are too descriptive and summarize better the key findings.

Thus, the following comments should be addressed prior to publication to ACP.  

General comments:

1. The authors have extrapolated the aerosol relevant parameters from 865 nm to 550 nm, a wavelength much more common in satellite retrievals. However, the discussion e.g., in lines 180-188 (and in general throughout the manuscript) would be more insightful if instead of comparing the known differences of these two wavelengths (e.g. higher AOD at shorter wavelength) the authors provided a comparison with other satellite based retrievals (literature based).
2. The paper is too descriptive, and unnecessarily long in some parts (e.g. Sec. 3.3.2). Consider shortening some parts, avoid repetitions and draw meaningful comparisons (e.g. with previous studies).

Specific comments:

1. The introduction should be extended, including major findings from previous studies in the study region.
2. Discussion of Fig. S2 (lines 197-213) can be reduced.
3. L 218-219: The authors should elaborate more on the two maxima observed.
4. Fig. 7 is very difficult to read at its current form. The authors could consider moving this figure to the supplement, and include another visualization of the daily values in the main manuscript (e.g. histogram).
5. A few typos, grammatical and syntactic mistakes need to be corrected.