The manuscript by Luca Stabile et al. presents the results of an
interesting measurement of the amount of secondary organic aerosol
particle emission after the use of domestic floor cleaning products.

In the introduction the authors adequately present the motivation for
exploring the SOA formation due to their health impact and present the
main mechanism contributing to the process in the outside environments.
Since the indoor formation is not well explored yet, this research is a
welcoming step in this direction. The authors reasonably assume ozone as
the main factor on VOC to SOA condensation and assume internal ozone
concentration to be totally correlated with the outside one, which in the
absence of other data and internal known sources is an acceptable
assumption. Next, a large set of domestic floor cleaning products was
harvested from local shops and tested in a laboratory experimental chamber
and in the office. The PM concentrations and size distributions were
determined with a CPC and FMPS detector in parallel, which both gave good
correlation.

From the experimental data, emission factors were calculated for all the
used chemicals in two forms, namely in resulting particles per millilitre
and, assuming usage of 100mL per square meter, also in particles per
square meter of wetted area. Also, it was shown that the SOA are forming
during process by seeing an increase in the size of the PM.

The outcome of the research is interesting for scientific and general
public. The authors found that all the used cleaning agents can be
separated into two groups: those that emit particles and those that do
not. It is interesting also that four of the chemicals bearing the ECO
friendly label fall into the group of non-emitters. It would be
interesting to correlate ingredients of the cleaning products with the
emission factors, however it is beyond the scope of this work. Authors
also give a brief comparison with other indoor sources of PM.

In my opinion this work is very interesting, solid, properly done,
evaluated and presented, therefore I recommend the publication of this
work in Indoor air, with only some minor calls for improvement.

1. In the chamber, the authors have measured the humidity and observed
   very small changes. Doing a naive calculation, almost 100g of water had to
   evaporate in about 5 minutes inside 4.7m3 chamber. At 26C and 50%
   humidity, absolute humidity is 11g/m3. If the chamber was closed, we would
   introduce 21g/m3 of water, total 32g/m3 which corresponds to over 100%
   humidity. I would expect quite a raise in relative humidity inside the box
   except if the ventilation was very good. The authors only say the chamber
   is "naturally ventilated". Please add more description about the openings
   of the chamber and try to access the rate of natural ventilation and
   explain the almost constant humidity for the duration of the experiment.

2. In statistics, the Standard deviation is an absolute quantity with the
   same unit as measured quantity. In this work, the authors always report
   Relative standard deviation (a.k.a. Coefficient of Variation) in percent,
   while naming it Standard deviation. Please make it consistent (in text and
   tables).

Should the authors keep the relative standard deviation in the results,
they should be careful when dealing with temperature and humidity! Current
calculation is wrong, because absolute standard deviation is divided by
the value of temperature in Centigrade scale (imagine the temperature is
zero!). Use absolute temperature scale (Kelvin) or, better, use proper
Standard deviation, not the Relative one. I don't believe relative
temperature change is of any meaning here.

Furthermore, the Indoor RH Standard deviation in Table 2 is ambiguous,
because the RH is in %, so is the Standard deviation and so is the
Relative standard deviation. In the present form, one can assume the RH
varies in value for 8 (roughly from 40 to 56), while the authors probably
had in mind it varies for 4 (44 to 52). Please, make numbers and naming of
the type of deviation consistent.

1. I would expect an estimation of uncertainty in EF, Table 3.

2. Please indicate in the captions of Figures 1-4 that the measurements
   were performed in the chamber. Now, all measurements are called "tests",
   Fig 5. and 6. state they were made in actual environment, it will be
   reader friendly to similarly indicate about 1-4 being measured in the
   chamber.

3. Please draw ticks marks above numbers on all axes in all plots.

4. This is more technical suggestion: make plots black & white friendly,
   so that also in BW print one could identify curves.

5. Please check the sentence in line 182 (One of...)

6. Line 238: humidity is given in degrees Centigrade.

The authors have adequately addressed all my remarks and corrected the paper. I suggest accepting the paper to Indoor Air.