Exposures to Carbon Monoxide in a Cookstove Intervention in Northern Ghana

Round 1

Reviewer 1 Report

Your paper is a good piece of paper but not very new and a number of similar paper already published. Therefore I have some comments:

Regarding Introduction: In introduction need to mention aim, objectives clearly and also in it important to justify your title in your introduction section

Methodology is not well defined for example it need to expand based on objectives and activity - what, why and how?

Results and Discussion: Results need to justify with some recent journal publication for example journal related to: Energy and Society

It is good to avoid reference/citation in conclusion section   

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

In the manuscript ID atmosphere-528090 entitled “Exposures to carbon monoxide in a cookstove intervention in Northern Ghana” authors present personal CO exposure results outcomes from a monitoring campaign, also reporting effect related to the stove group and other covariates. The manuscript is well written and of interest. Therefore, I suggest minor revision before publication, listed below:

1.       Table 1: Please pay attention to the caption (typing error)

2.       Table 1: I suggest to explain better information (for example: what does it means “SES) reported in the caption

3.       Table 1 – Sample: Can authors report here also the %, as reported in the text?

4.       Table 1: Can authors describe in the caption what each * refers to?

5.       Line 94-95: Can authors add more information regarding the certified standard?

6.       Line 94: I suggest to better explain what “in most cases” refers to (can you quantify it?)

7.       Equation 1: Can authors report in the text also the explanation of B0 and B1?

8.       Line 129 and 131: I suggest reporting the reference in a consistent manner (Awiri et al. 2010 and Oduro et al 2012).

9.       Line 170: In my opinion can be useful to add in the text some information (referring to reference 13)

10.   Figure 2 and figure 3: Can author better define in the captures “time of day”?

11.   Conclusions: In my opinion authors should better report here the scientific aim of the study, as well as the benefits of results.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Summary- This article presents 2-years measurements of CO and other pollutant concentrations measured via personal exposure monitors placed on several hundred participants in households using different cookstove arrangements in order to assess how cookstove models might influence CO exposure by individual household members. Despite a high degree of scatter, the measurements show that household members using new models of cookstoves experience 10-30% less CO exposure than households using traditional cooking methods. The quality of the measurements seems reasonable and well-documnented, and therefore these measurements should be published with some minor (possibly major) revisions where I think the measurements presented could be more meaningful for the readership.

Specific points:

1) There is no mention of personal cigarette smoking in the households where the monitors were placed. I thought CO/cigarette use was a pretty important factor, so please explain why this is missing from this study.

2) Table 1 is confusing. The control group is listed as 62 "participants", but the number of males + females adds up to 207. Maybe "participants" refers to households? and therefore there were quite a few households where multiple people in that household were monitored? Also, the number of "seasons" and SES numbers also adds up to 207. Are these numbers reported for season or SES person-days? What are the units of the numbers listed in Gender, SES, and Seasons? Please clarify.

3) I'm not familiar with the statistical techniques used in this field, and I'm curious about why CO concentrations are log-transformed? I guess it creates a multiple multiplicative regression assumption, rather than a simpler multiple linear regression of additive factors. However, this transformation seems useless and unnecessary, and also creates the "zero" problem. I assume that the arbitrary "zero" adjustment has essentially NO influence on any of the results presented here? (i.e. if a zero adjustment that is 2X higher than whatever is used here is employed, none of the numerical values presented in any of the tables would change appreciably? How sensitive are results presented to different zero adjustments?

4) Equation 1: Again I am not familiar with the numerics of how Eq. 1 is implemented, and when the authors use variables like "SES","Stove group", "Primary Cook*Gender" or "Season", there is an integer value or something that is fed into the regression?

5) On line 140, I am confused about the sentence which explains "Repeated measurements" Were there two monitors on some individual subjects? What is meant by "repeated measurements"?

6) Table 2 needs to clearly state the averaging time of the measured concentrations presented. On line 69 it is stated that 48-hr samples are used, but elsewhere daily averages are mentioned. How are 1-minute measurements averaged before all the regressions & comparisons are made?

7) On line 226 I am very surprised to see 1.16 PPM difference in side-by-side monitors. So some participants were rigged with TWO monitors? Please explain this protocol. Is this 1.16 ppm the average difference in a collection of 1-minute measurements, or a difference in 24-hr or 48 hr averages? Side-by-side monitors that report differences might not be errors, so this isn't necessarily "measurement errors". I thought the authors carefully calibrated all monitors and would discard ("flag"?) monitors that were appreciably out of calibration or something? maybe not, but please clarify. This casual mention of a HUGE discrepancy seems to undermine the whole study and while it doesn't make the results unpublishable, this needs to be in the abstract: We can't measure the "true" exposure level very accurately. A sentence in the abstract stating " the differences reported here are significantly smaller than the side-by-side differences in duplicate monitors on the same person averaged over 24-hr periods" (or whatever the averaging time is for the reported concentrations).

8) Figure 2 presents splined smoothed measurements. This is one revision I would like to see that probably involves a little work. "B-Spline smoothing" seems overly complex, and actually hides relevant information. Just present 2 or 3 hr averages. The authors note that confidence intervals are something nice. I don't think Fig. 2 shows the confidence intervals, and there is no need to show this, but if the authors want to show "confidence intervals" they could show "box-whisker" or even the mean and also the 10th & 90th percentiles of 1-minute minute measurements over the 3-hr averaging period plotted. If the authors don't want to add value to what they are showing (3-hr averages, which coincide with WMO exposure times) then they have to give the details of B-spline factors used.

9) When the authors note WMO standards, they use units of mg/m3, but all the measurements shown here are in ppm. When mentioning the WMO mg/m3 numbers, please add in parentheses the equivalent ppm whenever the mg/m3 numbers are presented. Use STP or whatever T,P you want.

10) on line 286, description of Fig. 3, the authors note that 8.2% of the "daily" samples exceed the 1-hr maximum. I'm a little confused about averaging times. The WMO standard is a 1-hr average, and what the authors are calling here "daily samples" are also 1-hr averages? I hope the authors are not comparing 1-hr and 24-hr average numerical values. This sentence should read "8.2% of the daily 1-hr average maximum samples exceeded..."

Author Response

Please see the attachment.

Author Response File: Author Response.pdf