Three reviewers have given their comments on the manuscript, each
finding only minor revisions are required and providing the authors
with a list of specific changes, which, once addressed, would make
the paper suitable for publication in GMD.

The authors' "response to reviewers" carefully addresses each of the
points raised and the paper is now suitable for publication.

However, I would like to make a suggestion, in relation to the change
in the article's title that has been made between the version as
revised after the Topical Editor Review (which added the words
"an evolving" into the title as it was originally submitted) and as
it is in the revised version.

The authors have chosen to revert the title back to its original form
(taking back out the distinction that the volatility was evolving).

The reason the authors have done that, is because one of the three
reviewers suggested that the title appeared "awkward".

However, I think the word "evolving" needs to go back into the title,
as it gives an immediate indication to the reader that the VBS
approach is specifically to represent how the volatility of the organic
aerosol is *changing* during its lifetime in the atmosphere (becoming
less volatile as it is oxidised).

The reverted title now says "including organic aerosol volatility" but
I would argue that any model that includes organic aerosol is making
some assumption about the volatility of the OA. Conventional OA
models will be assuming zero volatility for the OA -- but they will
still technically be assigning a volatility to the species. Just that it's zero.
Models that have one-way gas-to-particle-transfer from an oxidised
organic species are also making an implicit assumption on an average
volatility of that species when they assign a particular molar yield for
that condensing species production.

For these reasons, I feel it important to make clear to the reader that
the advent of the VBS is specifically to introduce an OA volatility that
varies (or evolves) as it gets older.

For that reason, I make a strong suggestion that the authors put the
word "evolving" (or alternatively the word "varying") back into the
title, so that it is immediately clear to the reader the nature of the
capability the VBS brings to the model.

Personally, I do not consider the word "evolving" to be awkward.
And note that the other two reviewers seemed happy with the title as was.

Ultimately however, this is a personal choice for the authors, to decide to
make the change or not -- the revised paper now explains clearly how
the VBS approach works, so the evolving volatility should be implicit
once the article is read.

But, to me, it makes sense to make a virtue of the capability the new
version of the model brings, and, therefore, to state it, up front, in the title.