Atmospheric pseudohalogen chemistry
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Atmospheric pseudohalogen chemistry
ACPD
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Atmospheric
pseudohalogen
chemistry
D. J. Lary
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Conclusions References
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Atmos. Chem. Phys. Discuss., 4, 5381–5405, 2004
www.atmos-chem-phys.org/acpd/4/5381/
SRef-ID: 1680-7375/acpd/2004-4-5381
© European Geosciences Union 2004
Atmospheric
Chemistry
and Physics
Discussions
Atmospheric pseudohalogen chemistry
D. J. Lary
1,2,3
1
Global Modelling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt,
MD, USA
2
GEST at the University of Maryland Baltimore County, Baltimore, MD, USA
3
Unilever Cambridge Centre, Dep. of Chemistry, University of Cambridge, Cambridge, UK
Received: 29 July 2004 – Accepted: 1 September 2004 – Published: 16 September 2004
Correspondence to: D. J. Lary (david.lary@umbc.edu)
5381
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
Title Page
Abstract Introduction
Conclusions References
Tables Figures
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Interactive Discussion
© EGU 2004
Atmos. Chem. Phys. Discuss., 4, 5381–5405, 2004
www.atmos-chem-phys.org/acpd/4/5381/
SRef-ID: 1680-7375/acpd/2004-4-5381
© European Geosciences Union 2004
Atmospheric
Chemistry
and Physics
Discussions
Atmospheric pseudohalogen chemistry
D. J. Lary
1,2,3
1
Global Modelling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt,
MD, USA
2
GEST at the University of Maryland Baltimore County, Baltimore, MD, USA
3
Unilever Cambridge Centre, Dep. of Chemistry, University of Cambridge, Cambridge, UK
Received: 29 July 2004 – Accepted: 1 September 2004 – Published: 16 September 2004
Correspondence to: D. J. Lary (david.lary@umbc.edu)
5381
Page 2
ACPD
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
Title Page
Abstract Introduction
Conclusions References
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Abstract
There are at least three reasons why hydrogen cyanide is likely to be significant for at-
mospheric chemistry. The first is well known, HCN is a product and marker of biomass
burning. However, if a detailed ion chemistry of lightning is considered then it is almost
certain than in addition to lightning producing NO
x
, it also produces HO
x
and HCN. Un-5
like NO
x
and HO
x
, HCN is long-lived and could therefore be a useful marker of lightning
activity. Observational evidence is considered to support this view. Thirdly, the chem-
ical decomposition of HCN leads to the production of small amounts of CN and NCO.
NCO can be photolyzed in the visible portion of the spectrum yielding N atoms. The
production of N atoms is significant as it leads to the titration of nitrogen from the atmo-10
sphere via N+N→N
2
. Normally the only modelled source of N atoms is NO photolysis
which happens largely in the UV Schumann-Runge bands. However, NCO photolysis
occurs in the visible and so could be involved in titration of atmospheric nitrogen in the
lower stratosphere and troposphere. HCN emission inventories are worthy of atten-
tion. The CN and NCO radicals have been termed pseudohalogens since the 1920s.15
They are strongly bound, univalent, radicals with an extensive and varied chemistry.
The products of the atmospheric oxidation of HCN are NO, CO and O
3
.N+CH
4
and
N+CH
3
OH are found to be important sources of HCN. Including the pseudohalogen
chemistry gives a small increase in ozone and total reactive nitrogen (NO
y
).
1. Introduction20
Since the discovery of the Antarctic ozone hole by Farman et al. (1985) the importance
of halogen radicals in determining the concentrations of atmospheric ozone has been
clearly demonstrated. However, it was only in the mid 1970s that the halogen radicals
were first recognized as a potential threat to ozone. In like manner, there may be
other radicals which play a role in ozone photochemistry. There are many natural and25
anthropogenic sources of compounds containing CN which can be released into the
5382
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
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Abstract Introduction
Conclusions References
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Abstract
There are at least three reasons why hydrogen cyanide is likely to be significant for at-
mospheric chemistry. The first is well known, HCN is a product and marker of biomass
burning. However, if a detailed ion chemistry of lightning is considered then it is almost
certain than in addition to lightning producing NO
x
, it also produces HO
x
and HCN. Un-5
like NO
x
and HO
x
, HCN is long-lived and could therefore be a useful marker of lightning
activity. Observational evidence is considered to support this view. Thirdly, the chem-
ical decomposition of HCN leads to the production of small amounts of CN and NCO.
NCO can be photolyzed in the visible portion of the spectrum yielding N atoms. The
production of N atoms is significant as it leads to the titration of nitrogen from the atmo-10
sphere via N+N→N
2
. Normally the only modelled source of N atoms is NO photolysis
which happens largely in the UV Schumann-Runge bands. However, NCO photolysis
occurs in the visible and so could be involved in titration of atmospheric nitrogen in the
lower stratosphere and troposphere. HCN emission inventories are worthy of atten-
tion. The CN and NCO radicals have been termed pseudohalogens since the 1920s.15
They are strongly bound, univalent, radicals with an extensive and varied chemistry.
The products of the atmospheric oxidation of HCN are NO, CO and O
3
.N+CH
4
and
N+CH
3
OH are found to be important sources of HCN. Including the pseudohalogen
chemistry gives a small increase in ozone and total reactive nitrogen (NO
y
).
1. Introduction20
Since the discovery of the Antarctic ozone hole by Farman et al. (1985) the importance
of halogen radicals in determining the concentrations of atmospheric ozone has been
clearly demonstrated. However, it was only in the mid 1970s that the halogen radicals
were first recognized as a potential threat to ozone. In like manner, there may be
other radicals which play a role in ozone photochemistry. There are many natural and25
anthropogenic sources of compounds containing CN which can be released into the
5382
Page 3
ACPD
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
Title Page
Abstract Introduction
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atmosphere. Many CN reactions are already considered when studying combustion
chemistry and interstellar clouds. This paper considers their importance in our own
atmosphere.
1.1. Properties
HCN (also called formonitrile) is a highly volatile, colorless, and extremely poisonous5
liquid (boiling point 26
◦
C, freezing point −14
◦
C). A solution of hydrogen cyanide in
water is called hydrocyanic acid, or prussic acid. It was discovered in 1782 by the
Swedish chemist, Carl Wilhelm Scheele, who prepared it from the pigment Prussian
blue (Britannica, 2003).
1.2. Observations10
It is surprising that HCN is so often overlooked as it has been observed on numerous
occasions over the last two decades (Yokelson et al., 2003; Singh et al., 2003; Zhao
et al., 2002; Rinsland et al., 2001, 2000; Zhao et al., 2000; Rinsland et al., 1999; Brad-
shaw et al., 1998; Rinsland et al., 1998a,b; Schneider et al., 1997; Mahieu et al., 1997;
Rinsland et al., 1996; Notholt et al., 1995; Mahieu et al., 1995; Toon et al., 1992b,a;15
Kopp, 1990; Jaramillo et al., 1989; Zander, 1988; Carli and Park, 1988; Jaramillo et al.,
1988; Abbas et al., 1987; Smith and Rinsland, 1985; Coffey et al., 1981). Recently
it has sometimes been considered as an “interference” for NO
y
observations, for ex-
ample, Bradshaw et al. (1998); Thompson et al. (1997); Kliner et al. (1997). How-
ever, regarding it as an “interference” overlooks its potential importance in atmospheric20
chemistry, particularly as Cicerone and Zellner (1983) deduced that HCN has a very
long residence time against rainout.
Figure 1 shows all the HCN observations made by the Atmospheric Trace Molecule
Spectroscopy Experiment (ATMOS) on the missions ATLAS-1, ATLAS-2, and ATLAS-3
(Rinsland et al., 1998a,b, 1996) together with a typical mid-latitude NO
y
profile. In the25
upper troposphere and lower stratosphere the HCN abundance is comparable to the
5383
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
Title Page
Abstract Introduction
Conclusions References
Tables Figures
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atmosphere. Many CN reactions are already considered when studying combustion
chemistry and interstellar clouds. This paper considers their importance in our own
atmosphere.
1.1. Properties
HCN (also called formonitrile) is a highly volatile, colorless, and extremely poisonous5
liquid (boiling point 26
◦
C, freezing point −14
◦
C). A solution of hydrogen cyanide in
water is called hydrocyanic acid, or prussic acid. It was discovered in 1782 by the
Swedish chemist, Carl Wilhelm Scheele, who prepared it from the pigment Prussian
blue (Britannica, 2003).
1.2. Observations10
It is surprising that HCN is so often overlooked as it has been observed on numerous
occasions over the last two decades (Yokelson et al., 2003; Singh et al., 2003; Zhao
et al., 2002; Rinsland et al., 2001, 2000; Zhao et al., 2000; Rinsland et al., 1999; Brad-
shaw et al., 1998; Rinsland et al., 1998a,b; Schneider et al., 1997; Mahieu et al., 1997;
Rinsland et al., 1996; Notholt et al., 1995; Mahieu et al., 1995; Toon et al., 1992b,a;15
Kopp, 1990; Jaramillo et al., 1989; Zander, 1988; Carli and Park, 1988; Jaramillo et al.,
1988; Abbas et al., 1987; Smith and Rinsland, 1985; Coffey et al., 1981). Recently
it has sometimes been considered as an “interference” for NO
y
observations, for ex-
ample, Bradshaw et al. (1998); Thompson et al. (1997); Kliner et al. (1997). How-
ever, regarding it as an “interference” overlooks its potential importance in atmospheric20
chemistry, particularly as Cicerone and Zellner (1983) deduced that HCN has a very
long residence time against rainout.
Figure 1 shows all the HCN observations made by the Atmospheric Trace Molecule
Spectroscopy Experiment (ATMOS) on the missions ATLAS-1, ATLAS-2, and ATLAS-3
(Rinsland et al., 1998a,b, 1996) together with a typical mid-latitude NO
y
profile. In the25
upper troposphere and lower stratosphere the HCN abundance is comparable to the
5383
Page 4
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Atmospheric
pseudohalogen
chemistry
D. J. Lary
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NO
y
present and should not be neglected. It is tantalizing that some of the tropical
vertical profiles seem to have a large peak in HCN close to the tropopause which may
be produced by lightning in regions of strong convective activity.
1.3. Likely sources
HCN is produced by biomass burning (Lobert et al., 1990; Hurst et al., 1994b; Yokelson5
et al., 1997b; Holzinger et al., 1999; Rinsland et al., 1999, 2000; Barber et al., 2003;
Li et al., 2003; Singh et al., 2003; Yokelson et al., 2003) since nitrogen in plant ma-
terial is mostly present as amino acids and upon combustion this nitrogen is emitted
as a variety of compounds including NH
3
, NO, NO
2
,N
2
O, organic nitriles and nitrates
(Holzinger et al., 1999; Yokelson et al., 1997a; Lee and Atkins, 1994; Hurst et al.,10
1994b,a; Kuhlbusch et al., 1991). There are many naturally occurring substances
yielding cyanide in their seeds, such as the pit of the wild cherry. It usually occurs
in combination with plant sugars. The tuberous edible plant of the spurge family called
cassava (also known as manioc, mandioc, or yuca) were used by primitive peoples to
produce HCN for poison darts and arrows. HCN is produced by other plants, bacteria15
and fungi.
In addition, aliphatic-amines are produced from animal husbandry and may be a
source of HCN (Schade and Crutzen, 1995). Schade and Crutzen (1995) measured
the emissions of volatile aliphatic amines and ammonia produced by the manure of
beef cattle, dairy cows, swine, laying hens and horses in livestock buildings. The amine20
emissions consisted almost exclusively of the three methylamines and correlated with
those of ammonia. Schade and Crutzen (1995) showed possible reaction pathways for
atmospheric methylamines. These included the speculative but possible production of
HCN.
There are many anthropogenic sources of compounds containing CN which can be25
released into the atmosphere. Cyanides are used in a variety of chemical processes
including fumigation, case hardening of iron and steel, electroplating and in the con-
centration of ores. Hydrogen cyanide is a highly volatile and extremely poisonous gas
5384
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Atmospheric
pseudohalogen
chemistry
D. J. Lary
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NO
y
present and should not be neglected. It is tantalizing that some of the tropical
vertical profiles seem to have a large peak in HCN close to the tropopause which may
be produced by lightning in regions of strong convective activity.
1.3. Likely sources
HCN is produced by biomass burning (Lobert et al., 1990; Hurst et al., 1994b; Yokelson5
et al., 1997b; Holzinger et al., 1999; Rinsland et al., 1999, 2000; Barber et al., 2003;
Li et al., 2003; Singh et al., 2003; Yokelson et al., 2003) since nitrogen in plant ma-
terial is mostly present as amino acids and upon combustion this nitrogen is emitted
as a variety of compounds including NH
3
, NO, NO
2
,N
2
O, organic nitriles and nitrates
(Holzinger et al., 1999; Yokelson et al., 1997a; Lee and Atkins, 1994; Hurst et al.,10
1994b,a; Kuhlbusch et al., 1991). There are many naturally occurring substances
yielding cyanide in their seeds, such as the pit of the wild cherry. It usually occurs
in combination with plant sugars. The tuberous edible plant of the spurge family called
cassava (also known as manioc, mandioc, or yuca) were used by primitive peoples to
produce HCN for poison darts and arrows. HCN is produced by other plants, bacteria15
and fungi.
In addition, aliphatic-amines are produced from animal husbandry and may be a
source of HCN (Schade and Crutzen, 1995). Schade and Crutzen (1995) measured
the emissions of volatile aliphatic amines and ammonia produced by the manure of
beef cattle, dairy cows, swine, laying hens and horses in livestock buildings. The amine20
emissions consisted almost exclusively of the three methylamines and correlated with
those of ammonia. Schade and Crutzen (1995) showed possible reaction pathways for
atmospheric methylamines. These included the speculative but possible production of
HCN.
There are many anthropogenic sources of compounds containing CN which can be25
released into the atmosphere. Cyanides are used in a variety of chemical processes
including fumigation, case hardening of iron and steel, electroplating and in the con-
centration of ores. Hydrogen cyanide is a highly volatile and extremely poisonous gas
5384
Page 5
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4, 5381–5405, 2004
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pseudohalogen
chemistry
D. J. Lary
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that is used in fumigation, ore concentration, and various other industrial processes.
Cyanogen, or oxalonitrile, (CN)
2
, is also used as a chemical intermediate and a fu-
migant. Hydrogen cyanide is used to prepare polyacrylonitrile fibres (known by the
generic name of acrylic) synthetic rubber, plastics, and in gas masers to produce a
wavelength of 3.34mm (Britannica, 2003). Acrylic fibres are spun from polymers con-5
sisting of at least 85% by weight of acrylonitrile units produced from ethylene oxide and
hydrocyanic acid.
Hydrogen cyanide is a combustion product which is a human hazard during domestic
and industrial fires. Some catalytic converters in bad repair can produce large amounts
of Hydrogen cyanide. Hydrogen cyanide is produced in large quantities for laboratory10
and commercial use by three principal methods: Treatment of sodium cyanide with
sulphuric acid, catalytic oxidation of a methane-ammonia mixture, and decomposition
of formamide (HCONH
2
).
We suggest that it is timely to compile HCN emission inventories.
It is interesting to note that the atmospheric measurements of HCN reported by15
Zander (1988) gave a mixing ratio for HCN in the Southern Hemisphere which was
approximately 5% higher than that for the Northern Hemisphere. This may be due to
biomass burning. It seems that in addition to HCN being a marker of biomass burning
it is also a marker for lightning.
1.4. HCN, HO
x
and lightning20
Emissions from CN radicals are occasionally observed from lightning disturbed air (Ci-
cerone and Zellner, 1983). In the atmosphere of Jupiter HCN is present with a con-
centration of about 2 ppbv and is thought to be produced by lightning in the convective
regions of Jupiter’s atmosphere (Britannica, 2003; Borucki et al., 1988, 1991). On Titan
HCN is also thought to be produced by lightning (Borucki et al., 1988). It may well be25
that lightning is a significant source of HCN, particularly due to its resistance to uptake
by aqueous media.
Lightning produces large scale ionisation in the atmosphere with temperatures of
5385
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D. J. Lary
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that is used in fumigation, ore concentration, and various other industrial processes.
Cyanogen, or oxalonitrile, (CN)
2
, is also used as a chemical intermediate and a fu-
migant. Hydrogen cyanide is used to prepare polyacrylonitrile fibres (known by the
generic name of acrylic) synthetic rubber, plastics, and in gas masers to produce a
wavelength of 3.34mm (Britannica, 2003). Acrylic fibres are spun from polymers con-5
sisting of at least 85% by weight of acrylonitrile units produced from ethylene oxide and
hydrocyanic acid.
Hydrogen cyanide is a combustion product which is a human hazard during domestic
and industrial fires. Some catalytic converters in bad repair can produce large amounts
of Hydrogen cyanide. Hydrogen cyanide is produced in large quantities for laboratory10
and commercial use by three principal methods: Treatment of sodium cyanide with
sulphuric acid, catalytic oxidation of a methane-ammonia mixture, and decomposition
of formamide (HCONH
2
).
We suggest that it is timely to compile HCN emission inventories.
It is interesting to note that the atmospheric measurements of HCN reported by15
Zander (1988) gave a mixing ratio for HCN in the Southern Hemisphere which was
approximately 5% higher than that for the Northern Hemisphere. This may be due to
biomass burning. It seems that in addition to HCN being a marker of biomass burning
it is also a marker for lightning.
1.4. HCN, HO
x
and lightning20
Emissions from CN radicals are occasionally observed from lightning disturbed air (Ci-
cerone and Zellner, 1983). In the atmosphere of Jupiter HCN is present with a con-
centration of about 2 ppbv and is thought to be produced by lightning in the convective
regions of Jupiter’s atmosphere (Britannica, 2003; Borucki et al., 1988, 1991). On Titan
HCN is also thought to be produced by lightning (Borucki et al., 1988). It may well be25
that lightning is a significant source of HCN, particularly due to its resistance to uptake
by aqueous media.
Lightning produces large scale ionisation in the atmosphere with temperatures of
5385
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pseudohalogen
chemistry
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around 30000K produced within a few microseconds. Both the ionisation and high
temperatures are significant for atmospheric chemistry, and the full implications are
usually completely overlooked, with attention paid almost exclusively to NO
x
. Ionisation
produced by cosmic rays and precipitating particles is well known to produce NO
x
and
HO
x
(Brasseur and Solomon, 1987). The ionisation associated with lightning is between5
six and fifteen orders of magnitude greater than that associated with cosmic rays (Boldi,
1992). It is therefore likely that elevated HO
x
should be associated with lightning (Hill,
1992). This has been both calculated (Boldi, 1992) and hinted at by observations of
elevated HO
x
in the vicinity of convective outflow (Jaegle et al., 1999). Calculations
suggest that there is a 5–6% increase in global lightning for every 1
◦
C of warming10
(Price and Rind, 1994), so if there is a lightning source of HO
x
global warming could
lead to a significant change in the oxidizing capacity of the atmosphere due to lightning
produced HO
x
alone.
Equilibrium thermodynamic calculations (Boldi, 1992) show that for the conditions
associated with a lightning strike in the terrestrial atmosphere we would expect be-15
tween 0.7 to 1 ppbv of HCN. If HCN is produced by lightning, then in the surrounding
air we would simultaneously expect elevated concentrations of both NO
x
and NO
y
. This
is exactly what ATMOS observed (ATMOS). For example, around a thousand observa-
tions of HCN were made during November 1994 as part of ATLAS3 (ATMOS). Among
these observations there were six anomalously high HCN observations of greater than20
0.7 ppbv, for which elevated concentrations of both NO
x
and NO
y
were also observed.
If one plots a scatter diagram of the HCN against NO
x
concentrations (Fig. 2), we find
that there is a strong correlation between HCN and NO
x
for high HCN concentrations.
This corresponds to the air parcels that have probably recently encountered lightning.
There is not a strong correlation for the lower HCN and NO
x
concentrations as NO
x
25
and HCN are not in chemical equilibrium.
There are several satellites which observe global lightning, but these had not been
launched at the time of the last ATMOS mission. However, for the six locations with
HCN concentrations greater than 0.7 ppbv visible satellite images show cloud cover
5386
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chemistry
D. J. Lary
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around 30000K produced within a few microseconds. Both the ionisation and high
temperatures are significant for atmospheric chemistry, and the full implications are
usually completely overlooked, with attention paid almost exclusively to NO
x
. Ionisation
produced by cosmic rays and precipitating particles is well known to produce NO
x
and
HO
x
(Brasseur and Solomon, 1987). The ionisation associated with lightning is between5
six and fifteen orders of magnitude greater than that associated with cosmic rays (Boldi,
1992). It is therefore likely that elevated HO
x
should be associated with lightning (Hill,
1992). This has been both calculated (Boldi, 1992) and hinted at by observations of
elevated HO
x
in the vicinity of convective outflow (Jaegle et al., 1999). Calculations
suggest that there is a 5–6% increase in global lightning for every 1
◦
C of warming10
(Price and Rind, 1994), so if there is a lightning source of HO
x
global warming could
lead to a significant change in the oxidizing capacity of the atmosphere due to lightning
produced HO
x
alone.
Equilibrium thermodynamic calculations (Boldi, 1992) show that for the conditions
associated with a lightning strike in the terrestrial atmosphere we would expect be-15
tween 0.7 to 1 ppbv of HCN. If HCN is produced by lightning, then in the surrounding
air we would simultaneously expect elevated concentrations of both NO
x
and NO
y
. This
is exactly what ATMOS observed (ATMOS). For example, around a thousand observa-
tions of HCN were made during November 1994 as part of ATLAS3 (ATMOS). Among
these observations there were six anomalously high HCN observations of greater than20
0.7 ppbv, for which elevated concentrations of both NO
x
and NO
y
were also observed.
If one plots a scatter diagram of the HCN against NO
x
concentrations (Fig. 2), we find
that there is a strong correlation between HCN and NO
x
for high HCN concentrations.
This corresponds to the air parcels that have probably recently encountered lightning.
There is not a strong correlation for the lower HCN and NO
x
concentrations as NO
x
25
and HCN are not in chemical equilibrium.
There are several satellites which observe global lightning, but these had not been
launched at the time of the last ATMOS mission. However, for the six locations with
HCN concentrations greater than 0.7 ppbv visible satellite images show cloud cover
5386
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chemistry
D. J. Lary
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as do the NCEP analyses (NCEP). Each of the six locations were in a costal region
or over land which is where most lightning activity occurs. The vertical structure of
the HCN profile may provide a good test for the hypothesis that HCN is produced by
lightning. During thunderstorms we expect a “C” shaped NO
x
profile (Pickering et al.,
1998), and so should also expect a “C” shaped HCN profile with enhanced HCN in the5
region between 5 and 14 km.
1.5. Previous modelling work
The only previous modelling studies of atmospheric HCN appear to be those of Ci-
cerone and Zellner (1983); Brasseur et al. (1985); Li et al. (2003); Singh et al. (2003)
who considered the earth’s current atmosphere and the studies of Zahnle (1986a,b)10
who presented a study of the likely HCN chemistry in the earth’s early atmosphere.
Cicerone and Zellner (1983) identified the major atmospheric losses of HCN. Li et al.
(2003) and Singh et al. (2003) showed that the main HCN loss is due to oceanic uptake.
This study expands the previous work by considering many N, CN and NCO re-
actions which are known to be important in flame chemistry. These reactions are15
considered for conditions relevant to the current atmosphere. Including these reac-
tions provides additional sources of HCN, not included by Cicerone and Zellner (1983);
Brasseur et al. (1985), and some of which were not included by Zahnle (1986a,b) ei-
ther. HCN photolysis is shown to be a minor loss for HCN.
2. Reasons to consider HCN20
Before systematically examining atmospheric CN
x
chemistry let us examine at least
three reasons why we should consider atmospheric HCN chemistry.
5387
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as do the NCEP analyses (NCEP). Each of the six locations were in a costal region
or over land which is where most lightning activity occurs. The vertical structure of
the HCN profile may provide a good test for the hypothesis that HCN is produced by
lightning. During thunderstorms we expect a “C” shaped NO
x
profile (Pickering et al.,
1998), and so should also expect a “C” shaped HCN profile with enhanced HCN in the5
region between 5 and 14 km.
1.5. Previous modelling work
The only previous modelling studies of atmospheric HCN appear to be those of Ci-
cerone and Zellner (1983); Brasseur et al. (1985); Li et al. (2003); Singh et al. (2003)
who considered the earth’s current atmosphere and the studies of Zahnle (1986a,b)10
who presented a study of the likely HCN chemistry in the earth’s early atmosphere.
Cicerone and Zellner (1983) identified the major atmospheric losses of HCN. Li et al.
(2003) and Singh et al. (2003) showed that the main HCN loss is due to oceanic uptake.
This study expands the previous work by considering many N, CN and NCO re-
actions which are known to be important in flame chemistry. These reactions are15
considered for conditions relevant to the current atmosphere. Including these reac-
tions provides additional sources of HCN, not included by Cicerone and Zellner (1983);
Brasseur et al. (1985), and some of which were not included by Zahnle (1986a,b) ei-
ther. HCN photolysis is shown to be a minor loss for HCN.
2. Reasons to consider HCN20
Before systematically examining atmospheric CN
x
chemistry let us examine at least
three reasons why we should consider atmospheric HCN chemistry.
5387
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2.1. Abundance
Figure 1 shows that in the upper troposphere and lower stratosphere the HCN abun-
dance is comparable to the NO
y
present.
2.2. Tracer
HCN is a long lived, low solubility (Cicerone and Zellner, 1983) gas. If as it seems5
HCN is produced by lightning (Britannica, 2003; Cicerone and Zellner, 1983; Borucki
et al., 1988, 1991) then as it is not rained out it may well prove to be an effective
tracer of lightning activity. Such a marker could be extremely valuable to complement
observations (Huntrieser et al., 1998; Kawakami et al., 1997; Hauf et al., 1995).
2.3. N atom source10
The main stratospheric sink of NO
y
is the reaction of N with NO
N + NO −→ N
2
+O(
3
P) (1)
with the main source of N atoms generally accepted to be the photolysis of NO
NO + hν −→ N +O(
3
P) λ≤189nm (2)
However, the photolysis of NCO is also a source of N atoms. The rate of N production15
due to NCO photolysis is calculated to be faster than that due to NO photolysis below
about 10 km.
NCO + hν −→ N + CO λ≤342 nm
Consequently, when pseudohalogen chemistry is included in the model there is a sig-
nificant increase (more than an order of magnitude) in the N atom concentration below20
10 km (Fig. 4).
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2.1. Abundance
Figure 1 shows that in the upper troposphere and lower stratosphere the HCN abun-
dance is comparable to the NO
y
present.
2.2. Tracer
HCN is a long lived, low solubility (Cicerone and Zellner, 1983) gas. If as it seems5
HCN is produced by lightning (Britannica, 2003; Cicerone and Zellner, 1983; Borucki
et al., 1988, 1991) then as it is not rained out it may well prove to be an effective
tracer of lightning activity. Such a marker could be extremely valuable to complement
observations (Huntrieser et al., 1998; Kawakami et al., 1997; Hauf et al., 1995).
2.3. N atom source10
The main stratospheric sink of NO
y
is the reaction of N with NO
N + NO −→ N
2
+O(
3
P) (1)
with the main source of N atoms generally accepted to be the photolysis of NO
NO + hν −→ N +O(
3
P) λ≤189nm (2)
However, the photolysis of NCO is also a source of N atoms. The rate of N production15
due to NCO photolysis is calculated to be faster than that due to NO photolysis below
about 10 km.
NCO + hν −→ N + CO λ≤342 nm
Consequently, when pseudohalogen chemistry is included in the model there is a sig-
nificant increase (more than an order of magnitude) in the N atom concentration below20
10 km (Fig. 4).
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3. Atmospheric CN
x
chemistry
Let us now consider the HCN chemistry depicted in Fig. 3 as simulated using the ex-
tensively validated AutoChem model (Lary et al., 1995; Fisher and Lary, 1995; Lary,
1996; Lary et al., 2003). The model is explicit and uses the adaptive-timestep, error
monitoring, Stoer and Bulirsch (1980) time integration scheme designed by Press et al.5
(1992) for stiff systems of equations. Photolysis rates are calculated using full spheri-
cal geometry and multiple scattering (Anderson, 1983; Lary and Pyle, 1991a,b; Meier
et al., 1982; Nicolet et al., 1982) corrected after Becker et al. (2000). The photolysis
rate used for each time step is obtained by ten point Gaussian-Legendre integration
(Press et al., 1992). In this study the model described a total of 49 species including10
CN, NCO and HCN. The model kinetic data is based on DeMore et al. (2000) with the
cyanide reactions coming from a variety of sources.
The eventual fate of most HCN released into the atmosphere is NO. Since HCN has
a long lifetime against rainout (Cicerone and Zellner, 1983), whereas NO
x
does not,
HCN can be transported from the regions where it is emitted and slowly release NO
x
15
away from the source regions. The net effect of HCN oxidation is summarized by the
following reaction sequence shown in the following:
HCN +OH −→ H
2
O + CN (3)
CN +O
2
−→ NCO +O (4)
NCO + hν −→ N + CO (5)20
N +O
2
−→ NO +O (6)
2O + 2O
2
−→ 2O
3
(7)
O
3
+ hν −→ O(
1
D) +O
2
(8)
O(
1
D) + H
2
O −→ 2OH (9)
Net : HCN + 3O
2
+ 2hν −→ CO +O
3
+ NO +OH25
Therefore including HCN chemistry provides a small additional source of NO
x
,O
3
and
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3. Atmospheric CN
x
chemistry
Let us now consider the HCN chemistry depicted in Fig. 3 as simulated using the ex-
tensively validated AutoChem model (Lary et al., 1995; Fisher and Lary, 1995; Lary,
1996; Lary et al., 2003). The model is explicit and uses the adaptive-timestep, error
monitoring, Stoer and Bulirsch (1980) time integration scheme designed by Press et al.5
(1992) for stiff systems of equations. Photolysis rates are calculated using full spheri-
cal geometry and multiple scattering (Anderson, 1983; Lary and Pyle, 1991a,b; Meier
et al., 1982; Nicolet et al., 1982) corrected after Becker et al. (2000). The photolysis
rate used for each time step is obtained by ten point Gaussian-Legendre integration
(Press et al., 1992). In this study the model described a total of 49 species including10
CN, NCO and HCN. The model kinetic data is based on DeMore et al. (2000) with the
cyanide reactions coming from a variety of sources.
The eventual fate of most HCN released into the atmosphere is NO. Since HCN has
a long lifetime against rainout (Cicerone and Zellner, 1983), whereas NO
x
does not,
HCN can be transported from the regions where it is emitted and slowly release NO
x
15
away from the source regions. The net effect of HCN oxidation is summarized by the
following reaction sequence shown in the following:
HCN +OH −→ H
2
O + CN (3)
CN +O
2
−→ NCO +O (4)
NCO + hν −→ N + CO (5)20
N +O
2
−→ NO +O (6)
2O + 2O
2
−→ 2O
3
(7)
O
3
+ hν −→ O(
1
D) +O
2
(8)
O(
1
D) + H
2
O −→ 2OH (9)
Net : HCN + 3O
2
+ 2hν −→ CO +O
3
+ NO +OH25
Therefore including HCN chemistry provides a small additional source of NO
x
,O
3
and
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CO. If there is a heterogeneous conversion (oxidation) of HCN then it may be more
important than described here, particularly in the upper troposphere.
3.1. HCN
Figure 1 shows the observed HCN profiles from ATMOS. Cicerone and Zellner (1983)
and Brasseur et al. (1985) were able to reproduce the tropospheric portion of the profile5
but not the stratospheric portion. They suggested that the discrepancy may be due to
an inappropriate OH concentration or HCN photolysis rate. The HCN photolysis rate
calculated by assuming HCN has the same absorption cross-section as HCl will be too
fast as Herzberg and Innes (1957) report a predissociation limit of 179 nm for HCN,
which means that the HCN photolysis rate is very small. This is confirmed by the10
calculations of Huebner et al. (1992).
Another likely possibility for the discrepancy is in-situ atmospheric production of
HCN. Such production can occur by several routes, most of which are very slow as
they involve the CN radical which is quickly removed by reaction with O
2
. For this
reason, an effective production will probably not involve CN. Zahnle (1986a) included15
the production of HCN caused by the reaction of N with CH
2
and CH
3
. Since CH
2
is
produced mainly by Lyman-α CH
4
photolysis, this source of HCN will be small in the
troposphere and stratosphere (these source are included in the model). The reaction
of N with CH
4
is the most important source of HCN in the model, and has a noticeable
effect on the calculated HCN concentration above 25 km. It was not included by Ci-20
cerone and Zellner (1983); Brasseur et al. (1985); Zahnle (1986a,b). The rate constant
was measured by Takahashi (1972) at 298K with N
2
as the bath gas as 25×10
−14
molecules
−1
cm
3
s
−1
.
N + CH
4
−→ HCN + H
2
+ H (10)
Ocean uptake is the dominant sink for HCN (Singh et al., 2003; Li et al., 2003). The25
main atmospheric loss of HCN is reaction with OH.
HCN +OH −→ H
2
O + CN
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CO. If there is a heterogeneous conversion (oxidation) of HCN then it may be more
important than described here, particularly in the upper troposphere.
3.1. HCN
Figure 1 shows the observed HCN profiles from ATMOS. Cicerone and Zellner (1983)
and Brasseur et al. (1985) were able to reproduce the tropospheric portion of the profile5
but not the stratospheric portion. They suggested that the discrepancy may be due to
an inappropriate OH concentration or HCN photolysis rate. The HCN photolysis rate
calculated by assuming HCN has the same absorption cross-section as HCl will be too
fast as Herzberg and Innes (1957) report a predissociation limit of 179 nm for HCN,
which means that the HCN photolysis rate is very small. This is confirmed by the10
calculations of Huebner et al. (1992).
Another likely possibility for the discrepancy is in-situ atmospheric production of
HCN. Such production can occur by several routes, most of which are very slow as
they involve the CN radical which is quickly removed by reaction with O
2
. For this
reason, an effective production will probably not involve CN. Zahnle (1986a) included15
the production of HCN caused by the reaction of N with CH
2
and CH
3
. Since CH
2
is
produced mainly by Lyman-α CH
4
photolysis, this source of HCN will be small in the
troposphere and stratosphere (these source are included in the model). The reaction
of N with CH
4
is the most important source of HCN in the model, and has a noticeable
effect on the calculated HCN concentration above 25 km. It was not included by Ci-20
cerone and Zellner (1983); Brasseur et al. (1985); Zahnle (1986a,b). The rate constant
was measured by Takahashi (1972) at 298K with N
2
as the bath gas as 25×10
−14
molecules
−1
cm
3
s
−1
.
N + CH
4
−→ HCN + H
2
+ H (10)
Ocean uptake is the dominant sink for HCN (Singh et al., 2003; Li et al., 2003). The25
main atmospheric loss of HCN is reaction with OH.
HCN +OH −→ H
2
O + CN
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If the HCl cross-section is used to calculate the HCN photolysis rate as was done by
Cicerone and Zellner (1983) and Brasseur et al. (1985) then above 35 km photolysis is
the most important loss of HCN. However, Herzberg and Innes (1957) report a predis-
sociation limit of 55 900 cm
−1
, 179 nm. This means that no photolysis would occur in
the important UV window and HCN photolysis is very slow.5
HCN + hν −→ H + CN λ≤179nm (11)
There is also a minor loss due to reaction with O(
3
P) and O(
1
D) (Fig. 4).
HCN +O(
3
P) −→ H + NCO (12)
HCN +O(
1
D) −→ OH + CN (13)
3.2. The cyanide radical, CN10
In the sunlit atmosphere CN is in photochemical equilibrium. CN has a very short
lifetime because of the very fast reaction of CN with O
2
. The lifetime varies between
about 10 ns and 60 s. The calculated CN profile is shown in Fig. 4.
The most important production channel for CN in the model km is
HCN +OH −→ H
2
O + CN15
The reaction is slightly endothermic at 298K, however, the reverse reaction is not a
significant source of HCN. In the upper atmosphere the reaction of HCN with O(
1
D)
and HCN photolysis each contribute a few percent to the overall production of CN.
HCN +O(
1
D) −→ OH + CN
The main loss of CN at all altitudes in the model is the rapid reaction of CN with O
2
20
which has two channels
CN +O
2
−→ NCO +O(
3
P)
∆H
R
=−173 4 kJMole
−1
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If the HCl cross-section is used to calculate the HCN photolysis rate as was done by
Cicerone and Zellner (1983) and Brasseur et al. (1985) then above 35 km photolysis is
the most important loss of HCN. However, Herzberg and Innes (1957) report a predis-
sociation limit of 55 900 cm
−1
, 179 nm. This means that no photolysis would occur in
the important UV window and HCN photolysis is very slow.5
HCN + hν −→ H + CN λ≤179nm (11)
There is also a minor loss due to reaction with O(
3
P) and O(
1
D) (Fig. 4).
HCN +O(
3
P) −→ H + NCO (12)
HCN +O(
1
D) −→ OH + CN (13)
3.2. The cyanide radical, CN10
In the sunlit atmosphere CN is in photochemical equilibrium. CN has a very short
lifetime because of the very fast reaction of CN with O
2
. The lifetime varies between
about 10 ns and 60 s. The calculated CN profile is shown in Fig. 4.
The most important production channel for CN in the model km is
HCN +OH −→ H
2
O + CN15
The reaction is slightly endothermic at 298K, however, the reverse reaction is not a
significant source of HCN. In the upper atmosphere the reaction of HCN with O(
1
D)
and HCN photolysis each contribute a few percent to the overall production of CN.
HCN +O(
1
D) −→ OH + CN
The main loss of CN at all altitudes in the model is the rapid reaction of CN with O
2
20
which has two channels
CN +O
2
−→ NCO +O(
3
P)
∆H
R
=−173 4 kJMole
−1
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branching ratio=094
−→ CO + NO
∆H
R
=−455 6 kJMole
−1
branching ratio=0 06 (14)
The branching ratio quoted was determined by Schmatjko and Wolfrum (1978). In the5
laboratory Basco (1965) found that there was a production of ozone due to the first
channel of this reaction in an excess of oxygen because it can be followed by
O(
3
P) +O
2
M
−→ O
3
Such a production of O
3
does occur in the model to a very small extent, but it is only
a small source of O
3
as the CN radicals are present in such small concentrations. In10
addition, the NO formed can then take part in catalytic destruction of O
3
.
Since CN is a pseudohalogen it might be expected that, like the halogens, it could
take part in the catalytic destruction of ozone, for example
CN +O
3
−→ NCO +O
2
∆H
R
=−565 4 kJMole
−1
(15)15
(16)
NCO +O(
3
P) −→ CN +O
2
∆H
R
=173 4 kJMole
−1
(17)
Net : O
3
+O(
3
P) −→ O
2
+O
2
20
Clearly the important difference between the pseudo-halogen CN and halogens such
as Cl and Br, involved in stratospheric ozone destruction, is the very marked difference
in their reactions with O
2
. Chlorine and bromine form weakly bound peroxides on
reaction with O
2
Cl +O
2
+M ↔ ClOO +M (18)25
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branching ratio=094
−→ CO + NO
∆H
R
=−455 6 kJMole
−1
branching ratio=0 06 (14)
The branching ratio quoted was determined by Schmatjko and Wolfrum (1978). In the5
laboratory Basco (1965) found that there was a production of ozone due to the first
channel of this reaction in an excess of oxygen because it can be followed by
O(
3
P) +O
2
M
−→ O
3
Such a production of O
3
does occur in the model to a very small extent, but it is only
a small source of O
3
as the CN radicals are present in such small concentrations. In10
addition, the NO formed can then take part in catalytic destruction of O
3
.
Since CN is a pseudohalogen it might be expected that, like the halogens, it could
take part in the catalytic destruction of ozone, for example
CN +O
3
−→ NCO +O
2
∆H
R
=−565 4 kJMole
−1
(15)15
(16)
NCO +O(
3
P) −→ CN +O
2
∆H
R
=173 4 kJMole
−1
(17)
Net : O
3
+O(
3
P) −→ O
2
+O
2
20
Clearly the important difference between the pseudo-halogen CN and halogens such
as Cl and Br, involved in stratospheric ozone destruction, is the very marked difference
in their reactions with O
2
. Chlorine and bromine form weakly bound peroxides on
reaction with O
2
Cl +O
2
+M ↔ ClOO +M (18)25
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Br +O
2
+M ↔ BrOO +M (19)
which rapidly decompose to give back the halogen, whereas CN reacts rapidly with
O2, as we have mentioned previously
CN +O
2
−→ NCO +O
CN +O
2
−→ CO + NO5
Yielding primarily NCO and O. If Cl or Br atoms reacted with O
2
in a similar way to CN,
there would be no ozone loss. So the CN radical behaves in a crucially, very different
manner to the halogens, preventing it from participating in an efficient ozone loss cycle.
The reaction CN+O
3
is thermodynamically very favorable but its rate constant has
not been determined. The NCO+O reaction to give CN as a product occurs in flames10
(Tsang, 1992). This reaction is endothermic at room temperature by 173KJ/Mole. So
this reaction has not been included in the reaction scheme. Consequently, with the
current chemical scheme the only way to convert the NCO formed by the reaction of
CN with O
3
back to CN is via HCN photolysis. Since HCN has a lifetime of about
5 months (Singh et al., 2003; Li et al., 2003) and HCN photolysis is extremely slow this15
is not an effective loss of O
3
.
The CN+O
2
reaction has a second channel which produces CO+NO and so can
either enhance the NO/NO
2
catalytic cycle, or enhance the production of odd oxygen
if it is followed by the formation and photolysis of NO
2
. Unlike the photolysis of NO
2
or
ClO, the photolysis of NCO, does not yield an oxygen atom20
NCO + hν −→ N + CO
and so is not a source of odd oxygen. However, it is a source of N atoms.
3.3. The NCO radical
NCO is in photochemical equilibrium throughout the sunlit atmosphere. The lifetime
varies from about 6 s at the surface down to about a second at 65 km. The calculated25
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Br +O
2
+M ↔ BrOO +M (19)
which rapidly decompose to give back the halogen, whereas CN reacts rapidly with
O2, as we have mentioned previously
CN +O
2
−→ NCO +O
CN +O
2
−→ CO + NO5
Yielding primarily NCO and O. If Cl or Br atoms reacted with O
2
in a similar way to CN,
there would be no ozone loss. So the CN radical behaves in a crucially, very different
manner to the halogens, preventing it from participating in an efficient ozone loss cycle.
The reaction CN+O
3
is thermodynamically very favorable but its rate constant has
not been determined. The NCO+O reaction to give CN as a product occurs in flames10
(Tsang, 1992). This reaction is endothermic at room temperature by 173KJ/Mole. So
this reaction has not been included in the reaction scheme. Consequently, with the
current chemical scheme the only way to convert the NCO formed by the reaction of
CN with O
3
back to CN is via HCN photolysis. Since HCN has a lifetime of about
5 months (Singh et al., 2003; Li et al., 2003) and HCN photolysis is extremely slow this15
is not an effective loss of O
3
.
The CN+O
2
reaction has a second channel which produces CO+NO and so can
either enhance the NO/NO
2
catalytic cycle, or enhance the production of odd oxygen
if it is followed by the formation and photolysis of NO
2
. Unlike the photolysis of NO
2
or
ClO, the photolysis of NCO, does not yield an oxygen atom20
NCO + hν −→ N + CO
and so is not a source of odd oxygen. However, it is a source of N atoms.
3.3. The NCO radical
NCO is in photochemical equilibrium throughout the sunlit atmosphere. The lifetime
varies from about 6 s at the surface down to about a second at 65 km. The calculated25
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NCO profile can be seen in Fig. 4. By far the most important production of NCO is due
to the fast reaction
CN +O
2
−→ NCO +O(
3
P)
The main loss of NCO in the model is
NCO +O
2
−→ NO + CO
2
(20)5
In the upper atmosphere the reaction with O(
3
P) also plays a role.
NCO +O(
3
P) −→ CO + NO (21)
4. Conclusions
In addition to NO
x
lightning it is suggested that it is also producing significant amounts
of HCN and possibly HO
x
. HCN is a stable, long-lived, sparingly soluble molecule with10
a long residence time against rain-out. Unlike NO
x
, HCN can act as a relatively inert
“marker” of lightning activity, and may thereby serve as a proxy for the total amount
of lightning activity in the atmosphere. The vertical structure of HCN observed during
thunderstorms may provide a good test for the hypothesis that HCN is produced by
lightning.15
NCO photolysis enhances the N atom concentration, and hence, enhances the rate
of NO
y
loss due to the reaction of N with NO. This additional source of N atoms is more
important than NO photolysis below 10 km. The NCO absorption cross-section does
not appear to have been measured and is one of the largest uncertainties in this study.
Acknowledgements. D. Lary thanks J. A. Pyle, Z. Levin, R. Toumi, C. Price and D. Shallcross20
for useful conversations. It is a pleasure to acknowledge: NASA for a distinguished Goddard
Fellowship in Earth Science; The Royal Society for a Royal Society University Research Fellow-
ship; The government of Israel for an Alon Fellowship; The NERC, EU, and ESA for research
support.
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NCO profile can be seen in Fig. 4. By far the most important production of NCO is due
to the fast reaction
CN +O
2
−→ NCO +O(
3
P)
The main loss of NCO in the model is
NCO +O
2
−→ NO + CO
2
(20)5
In the upper atmosphere the reaction with O(
3
P) also plays a role.
NCO +O(
3
P) −→ CO + NO (21)
4. Conclusions
In addition to NO
x
lightning it is suggested that it is also producing significant amounts
of HCN and possibly HO
x
. HCN is a stable, long-lived, sparingly soluble molecule with10
a long residence time against rain-out. Unlike NO
x
, HCN can act as a relatively inert
“marker” of lightning activity, and may thereby serve as a proxy for the total amount
of lightning activity in the atmosphere. The vertical structure of HCN observed during
thunderstorms may provide a good test for the hypothesis that HCN is produced by
lightning.15
NCO photolysis enhances the N atom concentration, and hence, enhances the rate
of NO
y
loss due to the reaction of N with NO. This additional source of N atoms is more
important than NO photolysis below 10 km. The NCO absorption cross-section does
not appear to have been measured and is one of the largest uncertainties in this study.
Acknowledgements. D. Lary thanks J. A. Pyle, Z. Levin, R. Toumi, C. Price and D. Shallcross20
for useful conversations. It is a pleasure to acknowledge: NASA for a distinguished Goddard
Fellowship in Earth Science; The Royal Society for a Royal Society University Research Fellow-
ship; The government of Israel for an Alon Fellowship; The NERC, EU, and ESA for research
support.
5394
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chemistry
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References
Abbas, M., Guo, J., Carli, B., Mencaraglia, F., Carlotti, M., and Nolt, I.: Stratospheric distribution
of HCN from far infrared observations, Geophys. Res. Lett., 14, 531–534, 1987. 5383
Anderson, D.: The troposphere-stratosphere radiation-field at twilight – A spherical model,
Planet. Space Sci., 31, 1517–1523, 1983. 53895
ATMOS: Data can be accessed from http://remus.jpl.nasa.gov. 5386
Barber, T. R., Lutes, C. C., Doorn, M. R. J., Fuchsman, P. C., Timmenga, H. J., and Crouch,
R. L.: Aquatic ecological risks due to cyanide releases from biomass burning, Chemosphere,
50, 343–348, 2003. 5384
Basco, N.: Reaction of Cyanogen Radicals with Oxygen, Proc. of the Royal Society of London10
Series a-Mathematical and Physical Sciences, 283, 302, 1965. 5392
Becker, G., Grooss, J., McKenna, D., and Muller, R.: Stratospheric photolysis frequencies:
Impact of an improved numerical solution of the radiative transfer equation, J. Atmos. Chem.,
37, 217–229, 2000. 5389
Boldi, R.: A model of the ion chemistry of electrified convection, Tech. Rep. 23, Center for15
global change Science, MIT, Department of Earth, Atmospheric and Planetary Sciences,
1992. 5386
Borucki, W., Giver, L., Mckay, C., Scattergood, T., and Parris, J.: Lightning production of hydro-
carbons and HCN on titan – laboratory measurements, ICARUS, 76, 125–134, 1988. 5385,
538820
Borucki, W., Dyer, J., Phillips, J., and Pham, P.: Pioneer venus orbiter search for venusian
lightning, J. Geophys. Res., 96, 11 033–11 043, 1991. 5385, 5388
Bradshaw, J., Sandholm, S., and Talbot, R.: An update on reactive odd-nitrogen measurements
made during recent NASA Global Tropospheric Experiment programs, J. Geophys. Res.,
103, 19 129–19 148, 1998. 538325
Brasseur, G. and Solomon, S.: Aeronomy of the Middle Atmosphere: Chemistry and Physics
of the Stratosphere and Mesosphere, Atmospheric Science Library, D. Reidel Pub. Co., 2nd
edn., 1987. 5386
Brasseur, G., Zellner, R., Derudder, A., and Arijs, E.: Is hydrogen-cyanide (HCN) a progenitor
of acetonitrile (CH
3
CN) in the atmosphere, Geophys. Res. Lett., 12, 117–120, 1985. 5387,30
5390, 5391
Britannica, E.: Encyclopaedia Britannica Ultimate Reference Suite 2004 DVD, Encyclopaedia
5395
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
Title Page
Abstract Introduction
Conclusions References
Tables Figures
Back Close
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Print Version
Interactive Discussion
© EGU 2004
References
Abbas, M., Guo, J., Carli, B., Mencaraglia, F., Carlotti, M., and Nolt, I.: Stratospheric distribution
of HCN from far infrared observations, Geophys. Res. Lett., 14, 531–534, 1987. 5383
Anderson, D.: The troposphere-stratosphere radiation-field at twilight – A spherical model,
Planet. Space Sci., 31, 1517–1523, 1983. 53895
ATMOS: Data can be accessed from http://remus.jpl.nasa.gov. 5386
Barber, T. R., Lutes, C. C., Doorn, M. R. J., Fuchsman, P. C., Timmenga, H. J., and Crouch,
R. L.: Aquatic ecological risks due to cyanide releases from biomass burning, Chemosphere,
50, 343–348, 2003. 5384
Basco, N.: Reaction of Cyanogen Radicals with Oxygen, Proc. of the Royal Society of London10
Series a-Mathematical and Physical Sciences, 283, 302, 1965. 5392
Becker, G., Grooss, J., McKenna, D., and Muller, R.: Stratospheric photolysis frequencies:
Impact of an improved numerical solution of the radiative transfer equation, J. Atmos. Chem.,
37, 217–229, 2000. 5389
Boldi, R.: A model of the ion chemistry of electrified convection, Tech. Rep. 23, Center for15
global change Science, MIT, Department of Earth, Atmospheric and Planetary Sciences,
1992. 5386
Borucki, W., Giver, L., Mckay, C., Scattergood, T., and Parris, J.: Lightning production of hydro-
carbons and HCN on titan – laboratory measurements, ICARUS, 76, 125–134, 1988. 5385,
538820
Borucki, W., Dyer, J., Phillips, J., and Pham, P.: Pioneer venus orbiter search for venusian
lightning, J. Geophys. Res., 96, 11 033–11 043, 1991. 5385, 5388
Bradshaw, J., Sandholm, S., and Talbot, R.: An update on reactive odd-nitrogen measurements
made during recent NASA Global Tropospheric Experiment programs, J. Geophys. Res.,
103, 19 129–19 148, 1998. 538325
Brasseur, G. and Solomon, S.: Aeronomy of the Middle Atmosphere: Chemistry and Physics
of the Stratosphere and Mesosphere, Atmospheric Science Library, D. Reidel Pub. Co., 2nd
edn., 1987. 5386
Brasseur, G., Zellner, R., Derudder, A., and Arijs, E.: Is hydrogen-cyanide (HCN) a progenitor
of acetonitrile (CH
3
CN) in the atmosphere, Geophys. Res. Lett., 12, 117–120, 1985. 5387,30
5390, 5391
Britannica, E.: Encyclopaedia Britannica Ultimate Reference Suite 2004 DVD, Encyclopaedia
5395
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ACPD
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pseudohalogen
chemistry
D. J. Lary
Title Page
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Tables Figures
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Britannica, Inc., 2003. 5383, 5385, 5388
Carli, B. and Park, J.: Simultaneous measurement of minor stratospheric constituents with
emission far-infrared spectroscopy, J. Geophys. Res., 29, 3851–3865, 1988. 5383
Cicerone, R. and Zellner, R.: The atmospheric chemistry of hydrogen-cyanide (HCN), J. Geo-
phys. Res., 88, 689–696, 1983. 5383, 5385, 5387, 5388, 5389, 5390, 53915
Coffey, M., Mankin, W., and Cicerone, R.: Spectroscopic detection of stratospheric hydrogen
cyanide, Science, 214, 333–335, 1981. 5383
DeMore, W. B., Howard, C. J., Sander, S. P., Ravishankara, A. R., Golden, D. M., Kolb, C. E.,
Hampson, R. F., Molina, M. J., and Kurylo, M. J.: Chemical Kinetics and Photochemical Data
for Use in Stratospheric Modeling, Supplement to Evaluation 12: Update of Key Reactions,10
JPL Publ. 00-3, 2000. 5389
Farman, J. C., Gardiner, B. G., and Shanklin, J. D.: Large Losses of Total Ozone in Antarctica
Reveal Seasonal ClO
x
/NO
x
Interaction, Nature, 315, 207–210, 1985. 5382
Fisher, M. and Lary, D.: Lagrangian 4-dimensional variational data assimilation of chemical-
species, Q. J. R. Meteorol. Soc., 121, 1681–1704, 1995. 538915
Hauf, T., Schulte, P., Alheit, R., and Schlager, H.: Rapid vertical trace gas-transport by an
isolated midlatitude thunderstorm, J. Geophys. Res., 100, 22 957–22 970, 1995. 5388
Herzberg, G. and Innes, K. K.: Ultraviolet Absorption Spectra of HCN and DCN, 1. The Alpha-X
and Beta-X Systems, Canadian Journal of Physics, 35, 842–879, 1957. 5390, 5391
Hill, R. D.: An Efficient Lightning Energy-Source on the Early Earth, Origins of Life and Evolution20
of the Biosphere, 22, 277–285, 1992. 5386
Holzinger, R., Warneke, C., Hansel, A., Jordan, A., Lindinger, W., Scharffe, D. H., Schade, G.,
and Crutzen, P. J.: Biomass burning as a source of formaldehyde, acetaldehyde, methanol,
acetone, acetonitrile, and hydrogen cyanide, Geophys. Res. Lett., 26, 1161–1164, 1999.
538425
Huebner, W. F., Keady, J., and Lyon, S.: Solar Photo Rates for Planetary Atmospheres and
Atmospheric Pollutants, Kluwer Academic Publishers, Dordrecht, The Netherlands, 1992.
5390
Huntrieser, H., Schlager, H., Feigl, C., and Holler, H.: Transport and production of NOx in
electrified thunderstorms: Survey of previous studies and new observations at midlatitudes,30
J. Geophys. Res., 103, 28 247–28 264, 1998. 5388
Hurst, D., Griffith, D., Carras, J., Williams, D., and Fraser, P.: Measurements of trace gases
emitted by australian savanna fires during the 1990 dry season, J. Atmos. Chem., 18, 33–
5396
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
Title Page
Abstract Introduction
Conclusions References
Tables Figures
Back Close
Full Screen / Esc
Print Version
Interactive Discussion
© EGU 2004
Britannica, Inc., 2003. 5383, 5385, 5388
Carli, B. and Park, J.: Simultaneous measurement of minor stratospheric constituents with
emission far-infrared spectroscopy, J. Geophys. Res., 29, 3851–3865, 1988. 5383
Cicerone, R. and Zellner, R.: The atmospheric chemistry of hydrogen-cyanide (HCN), J. Geo-
phys. Res., 88, 689–696, 1983. 5383, 5385, 5387, 5388, 5389, 5390, 53915
Coffey, M., Mankin, W., and Cicerone, R.: Spectroscopic detection of stratospheric hydrogen
cyanide, Science, 214, 333–335, 1981. 5383
DeMore, W. B., Howard, C. J., Sander, S. P., Ravishankara, A. R., Golden, D. M., Kolb, C. E.,
Hampson, R. F., Molina, M. J., and Kurylo, M. J.: Chemical Kinetics and Photochemical Data
for Use in Stratospheric Modeling, Supplement to Evaluation 12: Update of Key Reactions,10
JPL Publ. 00-3, 2000. 5389
Farman, J. C., Gardiner, B. G., and Shanklin, J. D.: Large Losses of Total Ozone in Antarctica
Reveal Seasonal ClO
x
/NO
x
Interaction, Nature, 315, 207–210, 1985. 5382
Fisher, M. and Lary, D.: Lagrangian 4-dimensional variational data assimilation of chemical-
species, Q. J. R. Meteorol. Soc., 121, 1681–1704, 1995. 538915
Hauf, T., Schulte, P., Alheit, R., and Schlager, H.: Rapid vertical trace gas-transport by an
isolated midlatitude thunderstorm, J. Geophys. Res., 100, 22 957–22 970, 1995. 5388
Herzberg, G. and Innes, K. K.: Ultraviolet Absorption Spectra of HCN and DCN, 1. The Alpha-X
and Beta-X Systems, Canadian Journal of Physics, 35, 842–879, 1957. 5390, 5391
Hill, R. D.: An Efficient Lightning Energy-Source on the Early Earth, Origins of Life and Evolution20
of the Biosphere, 22, 277–285, 1992. 5386
Holzinger, R., Warneke, C., Hansel, A., Jordan, A., Lindinger, W., Scharffe, D. H., Schade, G.,
and Crutzen, P. J.: Biomass burning as a source of formaldehyde, acetaldehyde, methanol,
acetone, acetonitrile, and hydrogen cyanide, Geophys. Res. Lett., 26, 1161–1164, 1999.
538425
Huebner, W. F., Keady, J., and Lyon, S.: Solar Photo Rates for Planetary Atmospheres and
Atmospheric Pollutants, Kluwer Academic Publishers, Dordrecht, The Netherlands, 1992.
5390
Huntrieser, H., Schlager, H., Feigl, C., and Holler, H.: Transport and production of NOx in
electrified thunderstorms: Survey of previous studies and new observations at midlatitudes,30
J. Geophys. Res., 103, 28 247–28 264, 1998. 5388
Hurst, D., Griffith, D., Carras, J., Williams, D., and Fraser, P.: Measurements of trace gases
emitted by australian savanna fires during the 1990 dry season, J. Atmos. Chem., 18, 33–
5396
Page 17
ACPD
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chemistry
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56, 1994a. 5384
Hurst, D. F., Griffith, D. W. T., and Cook, G. D.: Trace Gas Emissions from Biomass Burning in
Tropical Australian Savannas, J. Geophys. Res.-Atmos., 99, 16 441–16 456, 1994b. 5384
Jaegle, L., Jacob, D., Wennberg, P., Spivakovsky, C., Hanisco, T., Lanzendorf, E., Hintsa, E.,
Fahey, D., Keim, E., Proffitt, M., Atlas, E., Flocke, F., Schauffler, S., McElroy, C., Midwinter,5
C., Pfister, L., and Wilson, J.: Ozone production in the upper troposphere and the influence
of aircraft during SONEX: Approach of NO
x
-saturated conditions, Geophys. Res. Lett., 26,
3081–3084, 1999. 5386
Jaramillo, M., Dezafra, R. L., Barrett, J. W., Parrish, A., and Solomon, P. M.: Mm-Wave Obser-
vations of Stratospheric HCN at Tropical Latitudes, Geophys. Res. Lett., 15, 265–268, 1988.10
5383
Jaramillo, M., Dezafra, R. L., Barrett, J., Emmons, L. K., Solomon, P. M., and Parrish, A.:
Measurements of Stratospheric Hydrogen-Cyanide at McMurdo Station, Antarctica – Further
Evidence of Winter Stratospheric Subsidence, J. Geophys. Res.-Atmos., 94, 16 773–16 777,
1989. 538315
Kawakami, S., Kondo, Y., Koike, M., Nakajima, H., Gregory, G., Sachse, G., Newell, R., Browell,
E., Blake, D., Rodriguez, J., and Merrill, J.: Impact of lightning and convection on reactive
nitrogen in the tropical free troposphere, J. Geophys. Res., 102, 28 367–28 384, 1997. 5388
Kliner, D., Daube, B., Burley, J., and Wofsy, S.: Laboratory investigation of the catalytic reduc-
tion technique for measurement of atmospheric NO
y
, J. Geophys. Res., 102, 10 759–10 776,20
1997. 5383
Kopp, E.: Hydrogen Constituents of the Mesosphere Inferred from Positive-Ions – H2o, Ch4,
H2co, H2o2, and Hcn, J. Geophys. Res.-Atmos., 95, 5613–5630, 1990. 5383
Kuhlbusch, T., Lobert, J., Crutzen, P., and Warneck, P.: Molecular nitrogen emissions from
denitrification during biomass burning, Nature, 351, 135–137, 1991. 538425
Lary, D.: Gas phase atmospheric bromine photochemistry, J. Geophys. Res., 101, 1505–1516,
1996. 5389
Lary, D. and Pyle, J.: Diffuse-radiation, twilight, and photochemistry: 1., J. Atmos. Chem., 13,
373–392, 1991a. 5389
Lary, D. and Pyle, J.: Diffuse-radiation, twilight, and photochemistry: 2., J. Atmos. Chem., 13,30
393–406, 1991b. 5389
Lary, D., Chipperfield, M., and Toumi, R.: The potential impact of the reaction
OH+ClO−→HCl+O
2
on polar ozone photochemistry, J. Atmos. Chem., 21, 61–79, 1995.
5397
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
Title Page
Abstract Introduction
Conclusions References
Tables Figures
Back Close
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Print Version
Interactive Discussion
© EGU 2004
56, 1994a. 5384
Hurst, D. F., Griffith, D. W. T., and Cook, G. D.: Trace Gas Emissions from Biomass Burning in
Tropical Australian Savannas, J. Geophys. Res.-Atmos., 99, 16 441–16 456, 1994b. 5384
Jaegle, L., Jacob, D., Wennberg, P., Spivakovsky, C., Hanisco, T., Lanzendorf, E., Hintsa, E.,
Fahey, D., Keim, E., Proffitt, M., Atlas, E., Flocke, F., Schauffler, S., McElroy, C., Midwinter,5
C., Pfister, L., and Wilson, J.: Ozone production in the upper troposphere and the influence
of aircraft during SONEX: Approach of NO
x
-saturated conditions, Geophys. Res. Lett., 26,
3081–3084, 1999. 5386
Jaramillo, M., Dezafra, R. L., Barrett, J. W., Parrish, A., and Solomon, P. M.: Mm-Wave Obser-
vations of Stratospheric HCN at Tropical Latitudes, Geophys. Res. Lett., 15, 265–268, 1988.10
5383
Jaramillo, M., Dezafra, R. L., Barrett, J., Emmons, L. K., Solomon, P. M., and Parrish, A.:
Measurements of Stratospheric Hydrogen-Cyanide at McMurdo Station, Antarctica – Further
Evidence of Winter Stratospheric Subsidence, J. Geophys. Res.-Atmos., 94, 16 773–16 777,
1989. 538315
Kawakami, S., Kondo, Y., Koike, M., Nakajima, H., Gregory, G., Sachse, G., Newell, R., Browell,
E., Blake, D., Rodriguez, J., and Merrill, J.: Impact of lightning and convection on reactive
nitrogen in the tropical free troposphere, J. Geophys. Res., 102, 28 367–28 384, 1997. 5388
Kliner, D., Daube, B., Burley, J., and Wofsy, S.: Laboratory investigation of the catalytic reduc-
tion technique for measurement of atmospheric NO
y
, J. Geophys. Res., 102, 10 759–10 776,20
1997. 5383
Kopp, E.: Hydrogen Constituents of the Mesosphere Inferred from Positive-Ions – H2o, Ch4,
H2co, H2o2, and Hcn, J. Geophys. Res.-Atmos., 95, 5613–5630, 1990. 5383
Kuhlbusch, T., Lobert, J., Crutzen, P., and Warneck, P.: Molecular nitrogen emissions from
denitrification during biomass burning, Nature, 351, 135–137, 1991. 538425
Lary, D.: Gas phase atmospheric bromine photochemistry, J. Geophys. Res., 101, 1505–1516,
1996. 5389
Lary, D. and Pyle, J.: Diffuse-radiation, twilight, and photochemistry: 1., J. Atmos. Chem., 13,
373–392, 1991a. 5389
Lary, D. and Pyle, J.: Diffuse-radiation, twilight, and photochemistry: 2., J. Atmos. Chem., 13,30
393–406, 1991b. 5389
Lary, D., Chipperfield, M., and Toumi, R.: The potential impact of the reaction
OH+ClO−→HCl+O
2
on polar ozone photochemistry, J. Atmos. Chem., 21, 61–79, 1995.
5397
Page 18
ACPD
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
Title Page
Abstract Introduction
Conclusions References
Tables Figures
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5389
Lary, D. J., Khattatov, B., and Mussa, H. Y.: Chemical data assimilation: A case study of solar
occultation data from the ATLAS 1 mission of the Atmospheric Trace Molecule Spectroscopy
Experiment (ATMOS), J. Geophys. Res.-Atmos., 108, 2003. 5389
Lee, D. and Atkins, D.: Atmospheric ammonia emissions from agricultural waste combustion,5
Geophys. Res. Lett., 21, 281–284, 1994. 5384
Li, Q. B., Jacob, D. J., Yantosca, R. M., Heald, C. L., Singh, H. B., Koike, M., Zhao, Y. J.,
Sachse, G. W., and Streets, D. G.: A global three-dimensional model analysis of the atmo-
spheric budgets of HCN and CH3CN: Constraints from aircraft and ground measurements,
J. Geophys. Res.-Atmos., 108, , 2003. 5384, 5387, 5390, 539310
Lobert, J. M., Scharffe, D. H., Hao, W. M., and Crutzen, P. J.: Importance of Biomass Burning in
the Atmospheric Budgets of Nitrogen-Containing Gases, Nature, 346, 552–554, 1990. 5384
Mahieu, E., Rinsland, C. P., Zander, R., Demoulin, P., Delbouille, L., and Roland, G.: Vertical
Column Abundances of Hcn Deduced from Ground-Based Infrared Solar Spectra – Long-
Term Trend and Variability, J. Atmos. Chem., 20, 299–310, 1995. 538315
Mahieu, E., Zander, R., Delbouille, L., Demoulin, P., Roland, G., and Servais, C.: Observed
trends in total vertical column abundances of atmospheric gases from IR solar spectra
recorded at the Jungfraujoch, J. Atmos. Chem., 28, 227–243, 1997. 5383
Meier, R., Anderson, D., and Nicolet, M.: Radiation-field in the troposphere and stratosphere
from 240–1000 nm, 1., General-Analysis, Planet. Space Sci., 30, 923–933, 1982. 538920
NCEP: Data can be accessed from http://www.ncep.noaa.gov. 5387
Nicolet, M., Meier, R., and Anderson, D.: Radiation-field in the troposphere and stratosphere,
2. Numerical-Analysis, Planet. Space Sci., 30, 935–983, 1982. 5389
Notholt, J., Meier, A., and Peil, S.: Total column densities of tropospheric and stratospheric
trace gases in the undisturbed arctic summer atmosphere, J. Atmos. Chem., 20, 311–332,25
1995. 5383
Pickering, K., Wang, Y., Tao, W., Price, C., and Muller, J.: Vertical distributions of lightning NO
x
for use in regional and global chemical transport models, J. Geophys. Res., 103, 31 203–
31 216, 1998. 5387
Press, W., Teukolsky, S., Vetterling, W., and Flannery, B.: Numerical Recipes in Fortran – The30
Art of Scientific Computing, Cambridge Univ. Press, New York, 2nd edn., 1992. 5389
Price, C. and Rind, D.: Possible implications of global climate-change on global lightning distri-
butions and frequencies, J. Geophys. Res.-Atmos., 99, 10 823–10 831, 1994. 5386
5398
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
Title Page
Abstract Introduction
Conclusions References
Tables Figures
Back Close
Full Screen / Esc
Print Version
Interactive Discussion
© EGU 2004
5389
Lary, D. J., Khattatov, B., and Mussa, H. Y.: Chemical data assimilation: A case study of solar
occultation data from the ATLAS 1 mission of the Atmospheric Trace Molecule Spectroscopy
Experiment (ATMOS), J. Geophys. Res.-Atmos., 108, 2003. 5389
Lee, D. and Atkins, D.: Atmospheric ammonia emissions from agricultural waste combustion,5
Geophys. Res. Lett., 21, 281–284, 1994. 5384
Li, Q. B., Jacob, D. J., Yantosca, R. M., Heald, C. L., Singh, H. B., Koike, M., Zhao, Y. J.,
Sachse, G. W., and Streets, D. G.: A global three-dimensional model analysis of the atmo-
spheric budgets of HCN and CH3CN: Constraints from aircraft and ground measurements,
J. Geophys. Res.-Atmos., 108, , 2003. 5384, 5387, 5390, 539310
Lobert, J. M., Scharffe, D. H., Hao, W. M., and Crutzen, P. J.: Importance of Biomass Burning in
the Atmospheric Budgets of Nitrogen-Containing Gases, Nature, 346, 552–554, 1990. 5384
Mahieu, E., Rinsland, C. P., Zander, R., Demoulin, P., Delbouille, L., and Roland, G.: Vertical
Column Abundances of Hcn Deduced from Ground-Based Infrared Solar Spectra – Long-
Term Trend and Variability, J. Atmos. Chem., 20, 299–310, 1995. 538315
Mahieu, E., Zander, R., Delbouille, L., Demoulin, P., Roland, G., and Servais, C.: Observed
trends in total vertical column abundances of atmospheric gases from IR solar spectra
recorded at the Jungfraujoch, J. Atmos. Chem., 28, 227–243, 1997. 5383
Meier, R., Anderson, D., and Nicolet, M.: Radiation-field in the troposphere and stratosphere
from 240–1000 nm, 1., General-Analysis, Planet. Space Sci., 30, 923–933, 1982. 538920
NCEP: Data can be accessed from http://www.ncep.noaa.gov. 5387
Nicolet, M., Meier, R., and Anderson, D.: Radiation-field in the troposphere and stratosphere,
2. Numerical-Analysis, Planet. Space Sci., 30, 935–983, 1982. 5389
Notholt, J., Meier, A., and Peil, S.: Total column densities of tropospheric and stratospheric
trace gases in the undisturbed arctic summer atmosphere, J. Atmos. Chem., 20, 311–332,25
1995. 5383
Pickering, K., Wang, Y., Tao, W., Price, C., and Muller, J.: Vertical distributions of lightning NO
x
for use in regional and global chemical transport models, J. Geophys. Res., 103, 31 203–
31 216, 1998. 5387
Press, W., Teukolsky, S., Vetterling, W., and Flannery, B.: Numerical Recipes in Fortran – The30
Art of Scientific Computing, Cambridge Univ. Press, New York, 2nd edn., 1992. 5389
Price, C. and Rind, D.: Possible implications of global climate-change on global lightning distri-
butions and frequencies, J. Geophys. Res.-Atmos., 99, 10 823–10 831, 1994. 5386
5398
Page 19
ACPD
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pseudohalogen
chemistry
D. J. Lary
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Tables Figures
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Rinsland, C., Mahieu, E., Zander, R., Gunson, M., Salawitch, R., Chang, A., Goldman, A.,
Abrams, M., Abbas, M., Newchurch, M., and Irion, F.: Trends of OCS, HCN, SF
6
, CHClF
2
in
the lower stratosphere from 1985 and 1994 ATMOS experiment measurements near 30
◦
N
latitude, Geophys. Res. Lett., 23, 2349–2352, 1996. 5383
Rinsland, C., Gunson, M., Wang, P., Arduini, R., Baum, B., Minnis, P., Goldman, A., Abrams,5
M., Zander, R., Mahieu, E., Salawitch, R., Michelsen, H., Irion, F., and Newchurch, M.:
ATMOS/ATLAS-3 infrared profile measurements of trace gases in the November 1994 trop-
ical and subtropical upper troposphere, J. Quant. Spec. Rad. Trans., 60, 891–901, 1998a.
5383
Rinsland, C., Gunson, M., Wang, P., Arduini, R., Baum, B., Minnis, P., Goldman, A., Abrams,10
M., Zander, R., Mahieu, E., Salawitch, R., Michelsen, H., Irion, F., and Newchurch, M.:
ATMOS/ATLAS-3 infrared profile measurements of clouds in the tropical and subtropical up-
per troposphere, J. Quant. Spec. Rad. Trans., 60, 903–919, 1998b. 5383
Rinsland, C. P., Goldman, A., Murcray, F. J., Stephen, T. M., Pougatchev, N. S., Fishman, J.,
David, S. J., Blatherwick, R. D., Novelli, P. C., Jones, N. B., and Connor, B. J.: Infrared solar15
spectroscopic measurements of free tropospheric CO, C
2
H
6
, and HCN above Mauna Loa,
Hawaii: Seasonal variations and evidence for enhanced emissions from the Southeast Asian
tropical fires of 1997-1998, J. Geophys. Res.-Atmos., 104, 18 667–18 680, 1999. 5383, 5384
Rinsland, C. P., Mahieu, E., Zander, R., Demoulin, P., Forrer, J., and Buchmann, B.: Free
tropospheric CO, C
2
H
6
, and HCN above central Europe: Recent measurements from the20
Jungfraujoch station including the detection of elevated columns during 1998, J. Geophys.
Res.-Atmos., 105, 24 235–24 249, 2000. 5383, 5384
Rinsland, C. P., Meier, A., Griffith, D. W. T., and Chiou, L. S.: Ground-based measurements of
tropospheric CO, C
2
H
6
, and HCN from Australia at 34 degreesS latitude during 1997–1998,
J. Geophys. Res.-Atmos., 106, 20 913–20 924, 2001. 538325
Schade, G. and Crutzen, P.: Emission of aliphatic-amines from animal husbandry and their
reactions – potential source of N
2
O and HCN, J. Atmos. Chem., 22, 319–346, 1995. 5384
Schmatjko, K. J. and Wolfrum, J.: Reactions of Molecules in Defined Vibrational-States, 6.
Energy-Distribution in Reactions CN(V)+ O(
3
P), O
2
, Berichte Der Bunsen-Gesellschaft-
Physical Chemistry, Chemical Physics, 82, 419–428, 1978. 539230
Schneider, J., Burger, V., and Arnold, F.: Methyl cyanide and hydrogen cyanide measurements
in the lower stratosphere: Implications for methyl cyanide sources and sinks, J. Geophys.
Res., 102, 25 501–25506, 1997. 5383
5399
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
Title Page
Abstract Introduction
Conclusions References
Tables Figures
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© EGU 2004
Rinsland, C., Mahieu, E., Zander, R., Gunson, M., Salawitch, R., Chang, A., Goldman, A.,
Abrams, M., Abbas, M., Newchurch, M., and Irion, F.: Trends of OCS, HCN, SF
6
, CHClF
2
in
the lower stratosphere from 1985 and 1994 ATMOS experiment measurements near 30
◦
N
latitude, Geophys. Res. Lett., 23, 2349–2352, 1996. 5383
Rinsland, C., Gunson, M., Wang, P., Arduini, R., Baum, B., Minnis, P., Goldman, A., Abrams,5
M., Zander, R., Mahieu, E., Salawitch, R., Michelsen, H., Irion, F., and Newchurch, M.:
ATMOS/ATLAS-3 infrared profile measurements of trace gases in the November 1994 trop-
ical and subtropical upper troposphere, J. Quant. Spec. Rad. Trans., 60, 891–901, 1998a.
5383
Rinsland, C., Gunson, M., Wang, P., Arduini, R., Baum, B., Minnis, P., Goldman, A., Abrams,10
M., Zander, R., Mahieu, E., Salawitch, R., Michelsen, H., Irion, F., and Newchurch, M.:
ATMOS/ATLAS-3 infrared profile measurements of clouds in the tropical and subtropical up-
per troposphere, J. Quant. Spec. Rad. Trans., 60, 903–919, 1998b. 5383
Rinsland, C. P., Goldman, A., Murcray, F. J., Stephen, T. M., Pougatchev, N. S., Fishman, J.,
David, S. J., Blatherwick, R. D., Novelli, P. C., Jones, N. B., and Connor, B. J.: Infrared solar15
spectroscopic measurements of free tropospheric CO, C
2
H
6
, and HCN above Mauna Loa,
Hawaii: Seasonal variations and evidence for enhanced emissions from the Southeast Asian
tropical fires of 1997-1998, J. Geophys. Res.-Atmos., 104, 18 667–18 680, 1999. 5383, 5384
Rinsland, C. P., Mahieu, E., Zander, R., Demoulin, P., Forrer, J., and Buchmann, B.: Free
tropospheric CO, C
2
H
6
, and HCN above central Europe: Recent measurements from the20
Jungfraujoch station including the detection of elevated columns during 1998, J. Geophys.
Res.-Atmos., 105, 24 235–24 249, 2000. 5383, 5384
Rinsland, C. P., Meier, A., Griffith, D. W. T., and Chiou, L. S.: Ground-based measurements of
tropospheric CO, C
2
H
6
, and HCN from Australia at 34 degreesS latitude during 1997–1998,
J. Geophys. Res.-Atmos., 106, 20 913–20 924, 2001. 538325
Schade, G. and Crutzen, P.: Emission of aliphatic-amines from animal husbandry and their
reactions – potential source of N
2
O and HCN, J. Atmos. Chem., 22, 319–346, 1995. 5384
Schmatjko, K. J. and Wolfrum, J.: Reactions of Molecules in Defined Vibrational-States, 6.
Energy-Distribution in Reactions CN(V)+ O(
3
P), O
2
, Berichte Der Bunsen-Gesellschaft-
Physical Chemistry, Chemical Physics, 82, 419–428, 1978. 539230
Schneider, J., Burger, V., and Arnold, F.: Methyl cyanide and hydrogen cyanide measurements
in the lower stratosphere: Implications for methyl cyanide sources and sinks, J. Geophys.
Res., 102, 25 501–25506, 1997. 5383
5399
Page 20
ACPD
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
Title Page
Abstract Introduction
Conclusions References
Tables Figures
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Interactive Discussion
© EGU 2004
Singh, H. B., Salas, L., Herlth, D., Kolyer, R., Czech, E., Viezee, W., Li, Q., Jacob, D. J., Blake,
D., Sachse, G., Harward, C. N., Fuelberg, H., Kiley, C. M., Zhao, Y., and Kondo, Y.: In situ
measurements of HCN and CH3CN over the Pacific Ocean: Sources, sinks, and budgets, J.
Geophys. Res.-Atmos., 108, 2003. 5383, 5384, 5387, 5390, 5393
Smith, M. A. H. and Rinsland, C. P.: Spectroscopic Measurements of Atmospheric HCN at5
Northern and Southern Latitudes, Geophys. Res. Lett., 12, 5–8, 1985. 5383
Stoer, J. and Bulirsch, R.: Introduction to Numerical Analysis, Springer-Verlag, New York, 1980.
5389
Takahashi, S.: The reaction between methane and nitrogen atom, Mem. Def. Acad., Math.,
Phys., Chem. Eng. (Yokosuka, Jpn.), 12, 1972. 539010
Thompson, A., Singh, H., Stewart, R., Kucsera, T., and Kondo, Y.: A Monte Carlo study of
upper tropospheric reactive nitrogen during the Pacific Exploratory Mission in the Western
Pacific Ocean (PEM-West B), J. Geophys. Res., 102, 28 437–28 446, 1997. 5383
Toon, G., Farmer, C., Schaper, P., Lowes, L., and Norton, R.: Composition measurements of
the 1989 arctic winter stratosphere by airborne infrared solar absorption-spectroscopy, J.15
Geophys. Res., 97, 7939–7961, 1992a. 5383
Toon, G., Farmer, C., Schaper, P., Lowes, L., Norton, R., Schoeberl, M., Lait, L., and Newman,
P.: Evidence for subsidence in the 1989 arctic winter stratosphere from airborne infrared
composition measurements, J. Geophys. Res., 97, 7963–7970, 1992b. 5383
Tsang, W.: Chemical Kinetic Data-Base for Propellant Combustion – Reactions Involving Cn,20
Nco, and Hnco, J. Phys. Chem. Ref. Data, 21, 753–791, 1992. 5393
Yokelson, R., Susott, R., Ward, D., Reardon, J., and Griffith, D.: Emissions from smoldering
combustion of biomass measured by open-path Fourier transform infrared spectroscopy, J.
Geophys. Res., 102, 18 865–18 877, 1997a. 5384
Yokelson, R. J., Susott, R., Ward, D. E., Reardon, J., and Griffith, D. W. T.: Emissions from25
smoldering combustion of biomass measured by open-path Fourier transform infrared spec-
troscopy, J. Geophys. Res.-Atmos., 102, 18 865–18 877, 1997b. 5384
Yokelson, R. J., Bertschi, I. T., Christian, T. J., Hobbs, P. V., Ward, D. E., and Hao, W. M.: Trace
gas measurements in nascent, aged, and cloud-processed smoke from African savanna fires
by airborne Fourier transform infrared spectroscopy (AFTIR), J. Geophys. Res.-Atmos., 108,30
, 2003. 5383, 5384
Zahnle, K. J.: Photochemistry of Methane and the Formation of Hydrocyanic Acid (HCN) in the
Earths Early Atmosphere, J. Geophys. Res.-Atmos., 91, 2819–2834, 1986a. 5387, 5390
5400
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
Title Page
Abstract Introduction
Conclusions References
Tables Figures
Back Close
Full Screen / Esc
Print Version
Interactive Discussion
© EGU 2004
Singh, H. B., Salas, L., Herlth, D., Kolyer, R., Czech, E., Viezee, W., Li, Q., Jacob, D. J., Blake,
D., Sachse, G., Harward, C. N., Fuelberg, H., Kiley, C. M., Zhao, Y., and Kondo, Y.: In situ
measurements of HCN and CH3CN over the Pacific Ocean: Sources, sinks, and budgets, J.
Geophys. Res.-Atmos., 108, 2003. 5383, 5384, 5387, 5390, 5393
Smith, M. A. H. and Rinsland, C. P.: Spectroscopic Measurements of Atmospheric HCN at5
Northern and Southern Latitudes, Geophys. Res. Lett., 12, 5–8, 1985. 5383
Stoer, J. and Bulirsch, R.: Introduction to Numerical Analysis, Springer-Verlag, New York, 1980.
5389
Takahashi, S.: The reaction between methane and nitrogen atom, Mem. Def. Acad., Math.,
Phys., Chem. Eng. (Yokosuka, Jpn.), 12, 1972. 539010
Thompson, A., Singh, H., Stewart, R., Kucsera, T., and Kondo, Y.: A Monte Carlo study of
upper tropospheric reactive nitrogen during the Pacific Exploratory Mission in the Western
Pacific Ocean (PEM-West B), J. Geophys. Res., 102, 28 437–28 446, 1997. 5383
Toon, G., Farmer, C., Schaper, P., Lowes, L., and Norton, R.: Composition measurements of
the 1989 arctic winter stratosphere by airborne infrared solar absorption-spectroscopy, J.15
Geophys. Res., 97, 7939–7961, 1992a. 5383
Toon, G., Farmer, C., Schaper, P., Lowes, L., Norton, R., Schoeberl, M., Lait, L., and Newman,
P.: Evidence for subsidence in the 1989 arctic winter stratosphere from airborne infrared
composition measurements, J. Geophys. Res., 97, 7963–7970, 1992b. 5383
Tsang, W.: Chemical Kinetic Data-Base for Propellant Combustion – Reactions Involving Cn,20
Nco, and Hnco, J. Phys. Chem. Ref. Data, 21, 753–791, 1992. 5393
Yokelson, R., Susott, R., Ward, D., Reardon, J., and Griffith, D.: Emissions from smoldering
combustion of biomass measured by open-path Fourier transform infrared spectroscopy, J.
Geophys. Res., 102, 18 865–18 877, 1997a. 5384
Yokelson, R. J., Susott, R., Ward, D. E., Reardon, J., and Griffith, D. W. T.: Emissions from25
smoldering combustion of biomass measured by open-path Fourier transform infrared spec-
troscopy, J. Geophys. Res.-Atmos., 102, 18 865–18 877, 1997b. 5384
Yokelson, R. J., Bertschi, I. T., Christian, T. J., Hobbs, P. V., Ward, D. E., and Hao, W. M.: Trace
gas measurements in nascent, aged, and cloud-processed smoke from African savanna fires
by airborne Fourier transform infrared spectroscopy (AFTIR), J. Geophys. Res.-Atmos., 108,30
, 2003. 5383, 5384
Zahnle, K. J.: Photochemistry of Methane and the Formation of Hydrocyanic Acid (HCN) in the
Earths Early Atmosphere, J. Geophys. Res.-Atmos., 91, 2819–2834, 1986a. 5387, 5390
5400
Page 21
ACPD
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
Title Page
Abstract Introduction
Conclusions References
Tables Figures
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Zahnle, K. J.: Photochemistry of CH
4
and HCN in the Primitive Atmosphere, Origins of Life and
Evolution of the Biosphere, 16, 188–189, 1986b. 5387, 5390
Zander, R. et al. : Concentrations of carbonyl sulfide and hydrogen cyanide in the free
upper troposphere and lower stratosphere deduced from ATMOS/Spacelab-3 infrared solar
occultation spectra, J. Geophys. Res., 93, 1669–1678, 1988. 5383, 53855
Zhao, Y., Kondo, Y., Murcray, F. J., Liu, X., Koike, M., Irie, H., Strong, K., Suzuki, K., Sera,
M., and Ikegami, Y.: Seasonal variations of HCN over northern Japan measured by ground-
based infrared solar spectroscopy, Geophys. Res. Lett., 27, 2085–2088, 2000. 5383535
Zhao, Y., Strong, K., Kondo, Y., Koike, M., Matsumi, Y., Irie, H., Rinsland, C. P., Jones, N. B.,
Suzuki, K., Nakajima, H., Nakane, H., and Murata, I.: Spectroscopic measurements of tropo-
spheric CO, C
2
H
6
,C
2
H
2
, and HCN in northern Japan, J. Geophys. Res.-Atmos., 107, 2002.
5383
5401
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
Title Page
Abstract Introduction
Conclusions References
Tables Figures
Back Close
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Print Version
Interactive Discussion
© EGU 2004
Zahnle, K. J.: Photochemistry of CH
4
and HCN in the Primitive Atmosphere, Origins of Life and
Evolution of the Biosphere, 16, 188–189, 1986b. 5387, 5390
Zander, R. et al. : Concentrations of carbonyl sulfide and hydrogen cyanide in the free
upper troposphere and lower stratosphere deduced from ATMOS/Spacelab-3 infrared solar
occultation spectra, J. Geophys. Res., 93, 1669–1678, 1988. 5383, 53855
Zhao, Y., Kondo, Y., Murcray, F. J., Liu, X., Koike, M., Irie, H., Strong, K., Suzuki, K., Sera,
M., and Ikegami, Y.: Seasonal variations of HCN over northern Japan measured by ground-
based infrared solar spectroscopy, Geophys. Res. Lett., 27, 2085–2088, 2000. 5383535
Zhao, Y., Strong, K., Kondo, Y., Koike, M., Matsumi, Y., Irie, H., Rinsland, C. P., Jones, N. B.,
Suzuki, K., Nakajima, H., Nakane, H., and Murata, I.: Spectroscopic measurements of tropo-
spheric CO, C
2
H
6
,C
2
H
2
, and HCN in northern Japan, J. Geophys. Res.-Atmos., 107, 2002.
5383
5401
Page 22
ACPD
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Atmospheric
pseudohalogen
chemistry
D. J. Lary
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1E-011 1E-010 1E-009 1E-008 1E-007
HCN v.m.r.
1000
100
10
P
(
m
b
)
1994
1993
1992
NO
y
1000
100
10
1E-011 1E-010 1E-009
Fig. 1. All HCN observations made by the Atmospheric Trace Molecule Spectroscopy Experi-
ment (ATMOS) on the missions ATLAS-1 (1992), ATLAS-2 (1993), and ATLAS-3 (1994) shown
together with a typical mid-latitude NO
y
profile. The ATMOS data is publically available from
the web site http://remus.jpl.nasa.gov/.
5402
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
Title Page
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1E-011 1E-010 1E-009 1E-008 1E-007
HCN v.m.r.
1000
100
10
P
(
m
b
)
1994
1993
1992
NO
y
1000
100
10
1E-011 1E-010 1E-009
Fig. 1. All HCN observations made by the Atmospheric Trace Molecule Spectroscopy Experi-
ment (ATMOS) on the missions ATLAS-1 (1992), ATLAS-2 (1993), and ATLAS-3 (1994) shown
together with a typical mid-latitude NO
y
profile. The ATMOS data is publically available from
the web site http://remus.jpl.nasa.gov/.
5402
Page 23
ACPD
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
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1E-010 1E-009
HCN
1E-008
1E-007
N
O
x
1E-008
1E-007
1E-010 1E-009
1E-011 1E-010 1E-009
HCN
1E-012
1E-011
1E-010
1E-009
1E-008
1E-007
N
O
x
1E-011 1E-010 1E-009
1E-012
1E-011
1E-010
1E-009
1E-008
1E-007
Fig. 2. Scatter diagram of the HCN and NO
x
concentrations observed by ATMOS ATLAS3.
The left hand panel shows all the available HCN and NO
x
observations made. The right hand
panel is an enlargement showing just the high NO
x
and HCN concentrations which are probably
associated with lightning (notice the log-log scale).
5403
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
Title Page
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1E-010 1E-009
HCN
1E-008
1E-007
N
O
x
1E-008
1E-007
1E-010 1E-009
1E-011 1E-010 1E-009
HCN
1E-012
1E-011
1E-010
1E-009
1E-008
1E-007
N
O
x
1E-011 1E-010 1E-009
1E-012
1E-011
1E-010
1E-009
1E-008
1E-007
Fig. 2. Scatter diagram of the HCN and NO
x
concentrations observed by ATMOS ATLAS3.
The left hand panel shows all the available HCN and NO
x
observations made. The right hand
panel is an enlargement showing just the high NO
x
and HCN concentrations which are probably
associated with lightning (notice the log-log scale).
5403
Page 24
ACPD
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
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Fig. 3. The CN, NCO, HCN reaction scheme used in the model.
5404
4, 5381–5405, 2004
Atmospheric
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chemistry
D. J. Lary
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Fig. 3. The CN, NCO, HCN reaction scheme used in the model.
5404
Page 25
ACPD
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Atmospheric
pseudohalogen
chemistry
D. J. Lary
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© EGU 2004
0 20 40 60 80 100
0
10
20
30
40
50
60
70
80
% Contribution to loss of HCN
A
(
k
m
)
% Contribution to loss of HCN
HCN+O(
1
D)→CN+OH Bimolecular
HCN+OH→CN+H
2
O Bimolecular
HCN+hν→H+CN Photolysis
(a)
10
−35
10
−30
10
−25
10
−20
10
−15
10
−10
0
10
20
30
40
50
60
70
80
N
A
(
k
m
)
N
With
Without
(b)
−28
−27
−26
−25
−24
−23
−22
3 6 9 12 15 18 21
10
20
30
40
50
60
70
Local Solar Time (hours)
A
(
k
m
)
Log
10
(CN)
(c)
−27
−26
−25
−24
−23
−22
−21
−20
3 6 9 12 15 18 21
10
20
30
40
50
60
70
Local Solar Time (hours)
A
(
k
m
)
Log
10
(NCO)
(d)
Fig. 4. Panel (a) shows the calculated contributions for the various loss terms of HCN. Panel (b)
shows the effect on the nitrogen atom v.m.r. when cyanide chemistry is included. The red line
shows the calculation with pseudohalogen chemistry the blue line shows the calculation without
pseudohalogen chemistry. Panels (c) and (d) show calculated diurnal cycles for CN and NCO.
5405
4, 5381–5405, 2004
Atmospheric
pseudohalogen
chemistry
D. J. Lary
Title Page
Abstract Introduction
Conclusions References
Tables Figures
Back Close
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Print Version
Interactive Discussion
© EGU 2004
0 20 40 60 80 100
0
10
20
30
40
50
60
70
80
% Contribution to loss of HCN
A
(
k
m
)
% Contribution to loss of HCN
HCN+O(
1
D)→CN+OH Bimolecular
HCN+OH→CN+H
2
O Bimolecular
HCN+hν→H+CN Photolysis
(a)
10
−35
10
−30
10
−25
10
−20
10
−15
10
−10
0
10
20
30
40
50
60
70
80
N
A
(
k
m
)
N
With
Without
(b)
−28
−27
−26
−25
−24
−23
−22
3 6 9 12 15 18 21
10
20
30
40
50
60
70
Local Solar Time (hours)
A
(
k
m
)
Log
10
(CN)
(c)
−27
−26
−25
−24
−23
−22
−21
−20
3 6 9 12 15 18 21
10
20
30
40
50
60
70
Local Solar Time (hours)
A
(
k
m
)
Log
10
(NCO)
(d)
Fig. 4. Panel (a) shows the calculated contributions for the various loss terms of HCN. Panel (b)
shows the effect on the nitrogen atom v.m.r. when cyanide chemistry is included. The red line
shows the calculation with pseudohalogen chemistry the blue line shows the calculation without
pseudohalogen chemistry. Panels (c) and (d) show calculated diurnal cycles for CN and NCO.
5405
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