This paper presents a model which incorporates the extent of partitioning at emissions sources to explain observed non-equilibrium gas-particle partitioning trends for PAHs. Overall, I think the results are interesting and the paper highlights some interesting cases where the assumption of equilibrium partitioning at emissions is not valid – e.g. for coking when particles are being filtered out. I think that clarifying that this model is showing deviations from equilibrium K_p values rather than a “new” K_P value could maybe help here – along with more emphasis on comparing the measured results with a null-hypothesis of phi-nought = KpCa (emissions are at equilbirum conditions is the default assumption in most fate and transport models) rather than setting arbitrary values.

• Abstract – I think parts of the abstract could be re-worded.
• Lines 21 – 23 – here it would be more clear to describe the domains you observed
• Lines 25-29, I think rather than a description of results the actual results could be given, as the current form seems a little vague.
• Lines 53-61 – Here and throughout the use of K_p throughout the manuscript is somewhat problematic, since K_p is an equilibrium constant but the model presented here is not at equilibrium. I think the authors should clarify the differences here, and use a different symbol (e.g. K’_p) for non-equilbrium distribution between gas and particle. I also think fundamentally the equilibrium models and the non-equilibrium models are describing different things, so they are not directly comparable. In this section, the authors could expand on why in the real world assumptions of equilibrium are often not valid.
• Lines 108-109 – “it can be found…” This could be rephrased to be more direct e.g. “Four fluxes represented <XX% of overall mass transfer and were therefore removed from the system.” For instance from Fig. S1 it looks like gaseous wet deposition becomes somewhat important for e.g. DahA, making up a pretty large portion of the overall flux. Did you have some threshold you defined here?
• Line 120 – This looks like a derivation based on the fugacity capacity (Z value) – is that correct?
• Line 122– Again here I find the use of K_p I think this equation shows what you are doing – adjusting an equilibrium partition coefficient with a correction based on phi – rather than creating a new equilibrium rate constant. I think expressing this as a departure from equilibrium could also help the discussion elsewhere – for instance around Fig. 2,
• Equation 4 – You have simplified the equation such that it only depends on phi nought and kdeg but it also has a dependence on the parameters used to set-up the fugacity model. In particular, I would be interested to see what this looks like at different rain rates – the value you use (9.7e-5 m/h) from Mackay (2001) is going to vary substantially depending on location (presumably it was parameterized for a temperate climate like Ontario, Canada). Also, what about the assumed windspeed/ventilation coefficient – presumably, if you have little turnover the equilibrium assumption for G/P partitioning would get more accurate, whereas faster turnover would mean the initial G/P ratio would dominate.
• Line 197 – do you mean “deviation” here? Also, this is an interesting finding – are you assuming that degradation is only happening in the gas-phase?
• Line 235 – wouldn’t most modeling approaches show these to be mostly in the particle-phase anyways? I think the null-hypothesis here would be to assume equilibrium g/p partitioning at the emissions source rather than an arbitrary value?
• Line 246 – Ok here I see where this might apply! I think giving more examples like this makes sense and helps show where this model would be most useful – places where the emissions would not be at equilbirum (e.g. if they are at high temperatures, if the particles are being removed, etc.)
• Line 265-266 – what would be the equilibrium phi value for these compounds – is it close to 1? If so, then is this result telling us anything new?
• Implications – I think more could be done here showing how these limitations would impact the model. Could the authors run some sensitivity analyses?

The manuscript in its present form (after revision) seems to meet the quality requisites to publish.

Authors have made the changes/improvements required.

Best regards, 

AC