From the journal Environmental Science: Atmospheres Peer review history

29-Jun-2022

Dear Dr Roberts:

Manuscript ID: EA-ART-06-2022-000068
TITLE: Furoyl peroxynitrate (fur-PAN), a product of VOC-NOx photochemistry from biomass burning emissions: Photochemical synthesis, calibration, chemical characterization, and first atmospheric observations.

Thank you for your submission to Environmental Science: Atmospheres, published by the Royal Society of Chemistry. I sent your manuscript to reviewers and I have now received their reports which are copied below.

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Associate Editor, Environmental Science: Atmospheres

************

Reviewer 1

Roberts et al present a laboratory based characterisation of a newly found atmospheric PAN (fur-PAN) that is formed in wild-fires. The study includes the synthesis, detection (with CIMS and GC) and derivation of the most important physical-chemical constants that determine rates of thermal decomposition and dissolution of fur-PAN. The laboratory work is backed up by ambient measurements of fur-PAN and comparison with other wild-fire related emissions.
This work provides important and hitherto missing data that enables the lifetime and role of fur-PAN to be assessed. The manuscript is logically structured and clearly written. My comments are thus almost entirely minor and I recommend publication subsequent to minor corrections as outlined below.

General: The use of acronyms instead of chemical names or structures is fine. But why on earth does the word “wildfire” have to be abbreviated to WF ?? Saving 6 letters is not the point of using acronyms. I recommend changing this throughout the manuscript.

Section 2.6. The reaction time was calculated from the volume of the reactor and the flow rate. However, performing kinetics is rarely this simple and even in carefully characterised flow tubes (and this one appears to be a simple glass-vessel), the reaction time is not exactly equal to V/F but is impacted by different flow velocities (and directions) in different parts of the reactor. You can derive the true residence time by adding pulses of gas to the reactor or by conducting similar experiments with PAN for which k is well known. I would recommend the latter, as a comparison with PAN is made later anyway. Please assess the true uncertainty in the reaction time and thus in k.

Page 5, top left: “essentially exclusively” is not quantitative. Estimate what fraction of the Br recombines to form Br2, reacts with RO2, reacts with NO or NO2.

Page 5, top right: “The profiles of furoate and 4-oxo-2-butenoate ions from the fur-PAN source are plotted in Figure 3 as a function of PAN inlet temperature”. How does the IMR temperature in your system change with inlet temperature. Can this impact on the thermal decomposition rate constants that doe derive (e.g. because I- + RO2 becomes less/more efficient as e.g. in ref. 54) ?

Page 6, section 3.6. This section is out of place. I would move it to the end of the paper so you can discuss the ambient measurements with the data on thermal decomposition etc. already having been presented.

Page 7, top right. There are several slopes (not just one of 0.037) in Figure 6c. Please add some text describing what the origin of these different correlations might be. Also, in Figure 6b, please attempt to explain the intercept and the highly variable slope at low furfural mixing ratios.

Page 7, middle right: “The uncertainties in each rate constant were obtained by propagating the standard deviation of the average of 3–4 measurements before and after reaction” The analysis thus appears to neglect any analysis of systematic bias (e.g. in the reaction time or changing IMR efficiency with T as described in comments above).

Page 7, lower right. “The Arrhenius parameters obtained from the fit in Figure 7 are compared to parameters for other PAN compounds in Table 2.” Can the authors think of reasons why the preexponential factors vary so widely while the barrier to dissociation very similar is for each PAN. Can systematic bias as well as physical-effects play a role here ? In a similar vein, on page 8 (lower right) you state that PBzN “appears to be slightly more stable that fur-PAN” Is this statement supported by the data ? What uncertainties do e.g. IUPAC recommend for the thermal dissociation rate coefficients ?

Page 11, top right. “perhaps by a factor of 2 to 4”. Unless you can support this guesstimate with some calculations, I recommend removing it.

Page 10 top right. Several authors are not mentioned (SSB, MMC, CES, CW, JP).

Typos etc.:

As no line numbers are available, I have added comments to the PDF.

Reviewer 2

General comment

The study by Roberts et al. deals with detection and usage of furoyl peroxynitrate (fur-PAN) as marker for aged wildfire plumes. It follows a bottom-up approach from laboratory synthesis, behavior in an iodide chemical ionization mass spectrometer (I- CIMS) and quantification in a field measurement. The manuscript is well and stringently written, so I recommend it for publication after addressing some very minor comments below.


Specific comments

Page 2 left column

“Other PANs are generally less abundant than PAN,…”
Speciation of PAN is missing, I suppose acetyl peroxynitrate. I’d suggest to use PAN as acronym for the entire class of peroxyacyl nitrate and extended acronym for specific PAN as done in the manuscript with APAN.

“Solubility in n-octanol has only been measured for PAN”
Which PAN do you refer to?


Page2 right column

“This paper presents a method for the photochemical synthesis of fur-PAN using the photolysis of Br2 in the presence of furfural and nitric oxide (NO) in air.”
According to R3, this gives an alkyl radical, CO2 and NO2 without formation of PAN.


Page 4 left column

“The experimental set-up (schematic diagram shown in Figure S1) consisted of a PFA reaction volume (250 cc or 1000 cc nominal volumes), to which the fur-PAN source was added along with a 7.5 sccm of 100 ppmv NO in N2 mixture. The volumes of the reactors were measured by weighing them before and after filling them with water. The relatively high concentration of NO (5–15ppmv) prevented the reformation of fur-PAN by Reaction (3) so that the reaction rate being measured was that of Reaction (2).”
Reaction 2 shows the PAN decomposition by a collision molecule, Reaction 3 the conversion of a peroxyacyl radical to an alkyl radical by NO. Please revise.


Page 6 right column

Figure 5: After cyclisation, the radical character must remain. Please indicate that for the bicyclic reaction product at 150°C.


Page 7 right column

“An interesting aspect of these PANs is that the starting materials for APAN, acrolein and 1,3-butadiene, are derived from pyrolysis of lignin and the starting material for fur-PAN is derived from pyrolysis of cellulose and hemicellulose.6,7”
I’d suggest not to stress this too much, such small molecules used to originate from secondary decomposition reactions and less specific for a source rather than for the pyrolysis/combustion condition. Furfural is a major product from carbohydrate pyrolysis and its origin from lignin pyrolysis is negligible, but acrolein/butadiene have been found in cellulose pyrolysate (Katõ 1967 Agric Biolog Chem, Funazukuri 1989 JAAP). However, the yields of compound classes largely depend on the combustion/pyrolysis conditions. One may say that all fur-PAN precursors may be derived from biomass pyrolysis.


Page 9 right column

“…photochemistry from lignin-derived furanoids in WF plumes…”
Furans/furanoids are usually associated with the pyrolysis of carbohydrates, in context of biomass burning with cellulose and hemicellulose as you wrote in the introduction, only minor with lignin.



References


T. Funazukuri, R. R. Hudgins, P. L. Silveston (1989) Production of Olefins from Flash Pyrolysis of Cellulose-containing Material, Journal of Analytical and Applied Pyrolysis, 17, 47-66

K. Katō (1967) Pyrolysis of Cellulose, Agricultural and Biological Chemistry,
31:6, 657-663

REVIEWER REPORT(S):
Referee: 1

Comments to the Author
Roberts et al present a laboratory based characterisation of a newly found atmospheric PAN (fur-PAN) that is formed in wild-fires. The study includes the synthesis, detection (with CIMS and GC) and derivation of the most important physical-chemical constants that determine rates of thermal decomposition and dissolution of fur-PAN. The laboratory work is backed up by ambient measurements of fur-PAN and comparison with other wild-fire related emissions.
This work provides important and hitherto missing data that enables the lifetime and role of fur-PAN to be assessed. The manuscript is logically structured and clearly written. My comments are thus almost entirely minor and I recommend publication subsequent to minor corrections as outlined below.

General: The use of acronyms instead of chemical names or structures is fine. But why on earth does the word “wildfire” have to be abbreviated to WF ?? Saving 6 letters is not the point of using acronyms. I recommend changing this throughout the manuscript.
We have no great attachment to using the acronym, so we have changed to “wildfire”.

Section 2.6. The reaction time was calculated from the volume of the reactor and the flow rate. However, performing kinetics is rarely this simple and even in carefully characterised flow tubes (and this one appears to be a simple glass-vessel), the reaction time is not exactly equal to V/F but is impacted by different flow velocities (and directions) in different parts of the reactor. You can derive the true residence time by adding pulses of gas to the reactor or by conducting similar experiments with PAN for which k is well known. I would recommend the latter, as a comparison with PAN is made later anyway. Please assess the true uncertainty in the reaction time and thus in k.

The reactor is a hybrid between a plug-flow reactor and a continuous stirred tank reactor (CSTR) where the residence time is defined as the Volume/Flow rate and mixing relies partly on diffusion. The time scale for diffusive mixing is r2/3.6D, which for our reactors is on the order of 5-20 seconds, which would be the maximum uncertainty in the residence times in the reactor. The shorter mixing times correspond to the 250cc reactor operated at the highest temperatures (50C), which also correspond to the shortest residence times. The longer mixing times correspond to the 1000cc reactor operated at the lowest temperature (24°C) Consequently, the mixing times are much shorter than the residence times, 100-1620 seconds, so there would be at most a 5% uncertainty in the reaction times. Also, unlike linear flow tubes in which there can be induction times due to flow mixing and establishment of laminar flow, the analyte and carrier gas are already well mixed when they enter the reactor. To be conservative we have added 5% to the relative uncertainties of decay rates propagated from the GC runs. We have added the following text to the SI to explain these uncertainties:
“This reactor is a hybrid between a plug-flow reactor and a continuous stirred tank reactor (CSTR). In both kinds of reactors, the residence time is defined as the Volume/Flow Rate and mixing relies partly on diffusion. The time scale for diffusive mixing is r2/3.6D 1, which for our reactors is on the order of 5-20 seconds. This would be the maximum uncertainty in the residence times in the reactor. The shorter mixing times correspond to the 250cc reactor operated at the highest temperatures (50°C), which also correspond to the shortest residence times. The longer mixing times correspond to the 1000cc reactor operated at the lowest temperature (24°C) Consequently, the mixing times are much shorter than the residence times, 100-1620 seconds, so there would be at most a 5% uncertainty in the reaction times. Also, unlike linear flow tubes in which there can be induction times due to flow mixing and establishment of laminar flow, the analyte and carrier gas are already well mixed when they enter the reactor, so no such time offset pertains.”

In addition, we have added the following text to the main paper to note these uncertainties:
“and adding the uncertainty in reaction time discussed previously, in an RMS fashion.”

Page 5, top left: “essentially exclusively” is not quantitative. Estimate what fraction of the Br recombines to form Br2, reacts with RO2, reacts with NO or NO2.

That phrase was meant to refer to the site of reaction of the Br atoms with furfural, which is almost exclusively by abstraction of the aldehyde hydrogen. We are not aware of any measurements that would allow us to estimate rates of reaction at other sites on the molecule (by either ring-addition or H abstraction), as those are understood to be quite slow. We have added the following text to clarify what we meant:
“While Br atoms can react with other species in the system, for example by Br atom recombination, reaction with NO, NO2 or RO2 radicals, the reaction of Br atoms with furfural is thought to be exclusively by abstraction of the aldehyde hydrogen”

Page 5, top right: “The profiles of furoate and 4-oxo-2-butenoate ions from the fur-PAN source are plotted in Figure 3 as a function of PAN inlet temperature”. How does the IMR temperature in your system change with inlet temperature. Can this impact on the thermal decomposition rate constants that doe derive (e.g. because I- + RO2 becomes less/more efficient as e.g. in ref. 54) ?

We have measured the IMR temperature as a function of the PAN inlet temperature and it increased 12°C at the PAN inlet temperature of 200°C. Ref. 54 Figure 2, makes it clear that there is no temperature effect for the I- + RC(O)OO  RC(O)O- + IO reaction over a range of more than 20°C in IMR temperatures, in contrast to the clustering or ligand-switching reactions that are the subject of much of that paper. So, this IMR temperature variation had no effect on the response to RO2 species in the part of our work that varied PAN-inlet temperature. In addition, the PAN-inlet was kept at 150°C for the other experiments, so would have had no effect as those experiment only required a precise measurement that has a linear response over the applicable concentration range. We have added the following text to explain this with a ref to the original Ref 54:
“The PAN-inlet temperature has only a modest effect on the IMR temperature (12°C at an inlet temperature of 200°C), which has a negligible effect on the rate of R4.”

Page 6, section 3.6. This section is out of place. I would move it to the end of the paper so you can discuss the ambient measurements with the data on thermal decomposition etc. already having been presented.

OK-Done

Page 7, top right. There are several slopes (not just one of 0.037) in Figure 6c. Please add some text describing what the origin of these different correlations might be. Also, in Figure 6b, please attempt to explain the intercept and the highly variable slope at low furfural mixing ratios.

We have moved the Observations section to the end of the Results and Discussion. We have added text to explain the correlations in the absence of wildfire, and the intercept in Figure 6(b):
“The lowest furfural values (i.e. less than 0.1 ppbv) correspond to various urban sources, e.g. cooking, vehicles, that are much less abundant relative to urban CO. The x-intercept: CO  300ppbv can be interpreted as a mean urban value in the absence of a direct source.”

The data at low APAN in Figure 6C are again due to the variety of urban sources that we know are present, particularly vehicles, and perhaps volatile chemical products. To emphasize these other sources we have changed the text to:
“The wildfire photochemical products, APAN and PAN are also well correlated (R2 = 0.911) in the wildfire with a slope of 3.7%, much higher than slopes found in urban areas (less than or equal to 2%). The lowest APAN values (<10 pptv) correlate with PAN at a much lower slope, similar to what would be expected in an urban area that has typical vehicular and volatile chemical product sources.”

Page 7, middle right: “The uncertainties in each rate constant were obtained by propagating the standard deviation of the average of 3–4 measurements before and after reaction” The analysis thus appears to neglect any analysis of systematic bias (e.g. in the reaction time or changing IMR efficiency with T as described in comments above).

Yes, the uncertainties in reaction time might be 5% percent as discussed above- we have added those in as described above. There is no IMR temperature effect as explained above. Moreover, the thermal decomposition rate measurement involved keeping the PAN-inlet temperature at 150°C during all these experiments. The thermal reactor is completely separated from the system by the GC, so in any case, variations in reactor temperature would have no effect on the IMR temperature. We don’t feel this issue warrants further comment in the paper as the above explanation related to the PAN-inlet temperature tests, and the correct understanding of workings the thermal decomposition rate measurements, make it clear there is no such temperature effect.

Page 7, lower right. “The Arrhenius parameters obtained from the fit in Figure 7 are compared to parameters for other PAN compounds in Table 2.” Can the authors think of reasons why the preexponential factors vary so widely while the barrier to dissociation very similar is for each PAN.

Yes, you can think of the A factor as the intercept of the fit of lnk vs 1/T, and the data only extend over a relatively narrow range of temperatures (26° in this case) so the intercept of the fit ends up being less certain than the Ea as it is essentially lnk as T => infinity.

Can systematic bias as well as physical-effects play a role here?

It seems clear that all the uncertainties in the analyzes get amplified in this process, but it would be difficult to ascribe this variability to a single physical effect.
In a similar vein, on page 8 (lower right) you state that PBzN “appears to be slightly more stable that fur-PAN” Is this statement supported by the data ?
What uncertainties do e.g. IUPAC recommend for the thermal dissociation rate coefficients ?
IUPAC lists only PAN, PPN, and MPAN. There are a lot of PAN determinations, only a few PPN, and only one MPAN (actually by our first author more than 30 years ago). Among the PAN determinations, A factors vary over a factor of 4, same for PPN. The variations in A are somewhat correlated with Ea: lower A factors corresponding to slightly higher Ea, because of the way in which the data are fit. If we propagate the uncertainties in Arrhenius expression given in the reported PBzN measurement2, then the two determinations, PBzN and fur-PAN are not significantly different. One would need to compare measurements (and their uncertainties) made at a given temperature to see if a statistically significant difference was observed. Since these observations are not available, we will note that the k values at 298°K were not significantly different based on the uncertainties in the Arrhenius expressions. We have included the following text:
“although the uncertainties in the Arrhenius expressions are such that the k values at 298°K are not statistically different from one another.”

Page 11, top right. “perhaps by a factor of 2 to 4”. Unless you can support this guesstimate with some calculations, I recommend removing it.

Removed

Page 10 top right. Several authors are not mentioned (SSB, MMC, CES, CW, JP).

Those authors were involved in the ambient measurements during SUNVEx and have now been added.

Typos etc.:

As no line numbers are available, I have added comments to the PDF.

We have the following responses to the comments detailed on the pdf, in the order that they appear on the pdf.
All WF changed to wildfire
Furfural formula now given.
Added mid-latitude.
be was deleted
“species” changed to “trace gases”
“its” changed to “their”
Yes, aqueous – seemed clear enough, no change.
“rates” changed to “rate constant”
“of” deleted.
We now give two examples of “strong reagents”: hydrogen peroxide and concentrated sulfuric acid.
We have now added the suggested figure to the SI.
We have added “12 nm FHWM”.
Figure 1 caption: We now explain that the photochemical conversion of NO to NO2 in the source provides the NO2 for fur-PAN formation.
“Discreet” has been changed to “discrete”.
“tee” is the common terminology so we prefer to keep it.
Yes, there is no significant potential in the IMR to accelerate ions.
“volume” has been deleted.
The reaction time and associated uncertainties have been dealt with in the above detailed comments.
We have made the suggest change RE the GC sampling.
Now changed to “Ct/C0”
“to” changed to “for”
Sentence broken up as suggested.
“tee” is the more common usage, so we respectfully decline this change.
“were” changed to “was”
The units of RT are now specified.
We have the changed the description of Br chemistry as described above.
We routinely observed the common PAN compounds in room air, so we have now added the phrase “that were present in room air without any added chemical source.”
We have changed the symbols on Figure 3.
We have moved the “Observations of Fur-PAN…” section to the ends of the Results and Discussion.
“WF plume” changed to “wildfire emission”
“contributions” changed to “abundance”’
We have now included a range and reference several more papers in addition to the review chapter originally cited. We feel this is sufficient for a statement that was really meant to be a minor aside. We now say:
“As a matter of interest the PPN/PAN ratio (13.2%) is in the range that is typically observed in urban areas (10-16%) as is clear from the data from the remainder of the two-day period, and from other urban data sets3-6”.
We have added the word “urban” to specify the PAN-type compound to aldehyde ratios we were referring to.
There is no systematic error in the reaction time, but we now note that we add in the uncertainty in reaction time caused by mixing, as noted above. We have now added:
“and adding the uncertainty in reaction time discussed previously, in an RMS fashion.”
We have added “in the planetary boundary layer” after “atmospheric loss.”
PBzN vs fur-PAN values were not statistically different, added text: “although the uncertainties in the Arrhenius expressions are such that the k values at 298°K are not statistically different from one another.”
“The rate of exponential decay” changed to “The data were fit”
“seems to” changed to “can”
We eliminate the phrase “perhaps by a factor of 2 to 4.” Since we have no firm support for this estimate.
A 93% photolysis in about a 60sec residence time seems fairly “efficient” to us, but perhaps the word “facile” would be more appropriate here, so we have chosen it.
Have added the phrase “in ambient air masses”
We have added the other author contributions.

Referee: 2

Comments to the Author
General comment

The study by Roberts et al. deals with detection and usage of furoyl peroxynitrate (fur-PAN) as marker for aged wildfire plumes. It follows a bottom-up approach from laboratory synthesis, behavior in an iodide chemical ionization mass spectrometer (I- CIMS) and quantification in a field measurement. The manuscript is well and stringently written, so I recommend it for publication after addressing some very minor comments below.


Specific comments

Page 2 left column

“Other PANs are generally less abundant than PAN,…”
Speciation of PAN is missing, I suppose acetyl peroxynitrate. I’d suggest to use PAN as acronym for the entire class of peroxyacyl nitrate and extended acronym for specific PAN as done in the manuscript with APAN.

We are sorry for the confusion RE PAN acronyms. We disagree with the suggestion to use an extended acronym for the acetyl peroxynitrate compound, since its acronym, PAN, is so well established in the literature. Instead, we will use the term ”PAN-type compounds” when referring to the class of compounds, and “PAN” when referring to acetyl peroxynitrate.

“Solubility in n-octanol has only been measured for PAN”
Which PAN do you refer to?

With the above change in nomenclature, it should now be clear that we refer to PAN, acetyl peroxynitrate.


Page2 right column

“This paper presents a method for the photochemical synthesis of fur-PAN using the photolysis of Br2 in the presence of furfural and nitric oxide (NO) in air.”
According to R3, this gives an alkyl radical, CO2 and NO2 without formation of PAN.

We are sorry for the confusion, the photochemical source is much like that described originally by Warneck and Zerbach 19927, in that the initial reaction generates an excess of RO2 and HO2 radicals that convert NO to NO2, thus providing the NO2 required for PAN formation. The reason NO is used and not NO2 is that NO calibration mixtures of good purity and stability are readily available and NO2 standards are notoriously unstable over time. It has been found that reaction conditions can be controlled such that a stable high conversion (93%+ in our PAN sources) can be obtained (Volz-Thomas et al., 2002)8. This provides an excellent, stable calibration that is tied to our NO standards. The fur-PAN source was based on some of the features of the PAN source, so we used an NO standard and relied on excess radicals to convert NO to NO2.
We have now amended the text to make it clear how these photosources work:
The sentence “The important feature of these sources is that they avoid or minimize side-reactions of the organic-radical chemistry that can happen with the more reactive organic species such as conjugated carbonyls.” Is changed to “These photochemical sources rely on rapid formation of an excess of the desired RC(O)OO radical to convert a calibrated amount of an NO standard to NO2, through reaction R3 and subsequent reactions of hydroperoxyl radicals with NO. The desired PAN compound is then formed through R1. Conditions can be devised such that a stable, highly efficient (93%+) conversion of the NO standard can be achieved and used as a stable calibrant7-9.”

Page 4 left column

“The experimental set-up (schematic diagram shown in Figure S1) consisted of a PFA reaction volume (250 cc or 1000 cc nominal volumes), to which the fur-PAN source was added along with a 7.5 sccm of 100 ppmv NO in N2 mixture. The volumes of the reactors were measured by weighing them before and after filling them with water. The relatively high concentration of NO (5–15ppmv) prevented the reformation of fur-PAN by Reaction (3) so that the reaction rate being measured was that of Reaction (2).”
Reaction 2 shows the PAN decomposition by a collision molecule, Reaction 3 the conversion of a peroxyacyl radical to an alkyl radical by NO. Please revise.

We are sorry for the mistake, Reaction (1) would constitute the reformation of fur-PAN we have now changed the text to read:
“prevented the reformation of fur-PAN by Reaction (1) so that the reaction rate being measured was that of Reaction (2).”

Page 6 right column

Figure 5: After cyclisation, the radical character must remain. Please indicate that for the bicyclic reaction product at 150°C.

DONE

Page 7 right column

“An interesting aspect of these PANs is that the starting materials for APAN, acrolein and 1,3-butadiene, are derived from pyrolysis of lignin and the starting material for fur-PAN is derived from pyrolysis of cellulose and hemicellulose.6,7”
I’d suggest not to stress this too much, such small molecules used to originate from secondary decomposition reactions and less specific for a source rather than for the pyrolysis/combustion condition. Furfural is a major product from carbohydrate pyrolysis and its origin from lignin pyrolysis is negligible, but acrolein/butadiene have been found in cellulose pyrolysate (Katõ 1967 Agric Biolog Chem, Funazukuri 1989 JAAP). However, the yields of compound classes largely depend on the combustion/pyrolysis conditions. One may say that all fur-PAN precursors may be derived from biomass pyrolysis.

We agree that the distinction is not as clear cut as we have stated, and that the APAN precursors can also be found in the pyrolysis of cellulosic materials. We have adjusted the text to reflect this, although we still expect that the relative amounts of these PAN-type compounds will vary with fuel composition. The sentence now reads:
“An interesting aspect of these PAN-type compounds is that the starting materials for APAN, acrolein and 1,3-butadiene, are derived from pyrolysis of lignin and cellulosic fuels10, 11, and the starting material for fur-PAN is derived from pyrolysis of cellulose and hemi-cellulose.12, 13”

Page 9 right column

“…photochemistry from lignin-derived furanoids in WF plumes…”
Furans/furanoids are usually associated with the pyrolysis of carbohydrates, in context of biomass burning with cellulose and hemicellulose as you wrote in the introduction, only minor with lignin.

We thank the reviewer for catching this mistake, we have now corrected it:
“…photochemistry from cellulose/hemicellulose-derived furanoids in wildfire plumes…”


References


T. Funazukuri, R. R. Hudgins, P. L. Silveston (1989) Production of Olefins from Flash Pyrolysis of Cellulose-containing Material, Journal of Analytical and Applied Pyrolysis, 17, 47-66

K. Katō (1967) Pyrolysis of Cellulose, Agricultural and Biological Chemistry,
31:6, 657-663


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15-Jul-2022

Dear Dr Roberts:

Manuscript ID: EA-ART-06-2022-000068.R1
TITLE: Furoyl peroxynitrate (fur-PAN), a product of VOC-NOx photochemistry from biomass burning emissions: Photochemical synthesis, calibration, chemical characterization, and first atmospheric observations.

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