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348 Analytical Techniques for Atmospheric Measurement

therefore the amount of radicals produced, given the cross section for H

O. Schultz

et al. (1995) note such a system is versatile since CO can be added to convert all of the

OH to HO

, or that a hydrocarbon can be used instead of CO, so that an instrument

can be calibrated for specific RO

radicals that derive from the hydrocarbon. An early

difficulty with the technique centered on an uncertainty in the H

O cross section, but

later measurements have converged on a newly accepted value, about 30% higher than

the prior one (Cantrell et al., 1997; Hofzumahaus et al., 1997; Creasey et al., 2000). The

cross section can also be problematic as it exhibits a lot of structure in the vicinity of

185 nm, and the actual spectrum from the Hg lamps used may vary with its operating

conditions (current, temperature, age) and with the optical depth between the lamp and

the volume photolyzed (Cantrell et al., 1997; Lanzendorf et al., 1997). However, if care

is taken to determine the actinic flux with conditions that match those in effect for the

calibration, then this method is reliable (Creasey et al., 2000). Alternatively, rather

than accomplishing actinometry via O

absorption, N

O absorption may be employed

coupled with a chemiluminescence instrument to measure the NO so produced (Edwards

et al., 2003). An additional photolytic calibration technique employs the photolysis of

I at 254 nm in the presence of O

to produce CH

(Clemitshaw et al., 1997),

with the actinometry accomplished by monitoring the decay of CH

I with an absorption

measurement at 265 nm.

A significant dependence of chain length on H

O has been discovered and investigated.

Mihele and co-workers (Mihele & Hastie, 1998; Mihele et al., 1999) found a reduction

in chain length of a factor of 2 at a relative humidity of 40%, and they attributed this

to increased uptake of radicals on the walls with an increase in relative humidity. Mihele

and Hastie (2000) determined that it could be significantly improved by heating the walls

of the reactor and reducing the residence time there. Also, they derived a correction to

the chain length that is a function of relative humidity. On the other hand, Reichert et al.

(2003) determined that the H

O effect is not all due to walls, but that it also involves

water complexes. No matter the cause it would seem that the older PERCA measurements

are in need of correction for this effect.

A variation on PERCA is the use of laser-induced fluorescence (LIF, Chapter 4) to

measure NO

rather than luminol. This avoids problems of specificity associated with

the luminol technique (especially O

), and there is potential for improved time response

as well. However, the technique is still susceptible to uncertainties due to background

variability, but this should be smaller, as O

does not contribute. Sadanaga et al. (2004)

describe such an instrument which uses the same amplification chemistry as standard

PERCAs, as well as substituting N

for CO for background determination. It also uses

O photolysis at 185 nm coupled with O

actinometry to provide an HO

calibration.

For a 1 min integration time the detection limit (S/N = 2) of the instrument is in the

range of 2–4 pptv, depending on ambient relative humidity (and assuming 30 ppbv O

and 20 ppbv NO

.

Instruments using PERCA are typically deployed on the ground (e.g. Monks et al., 1996;

Clemitshaw et al., 1997; Handisides et al., 2003). For a study at the Mauna Loa Obser-

vatory, Cantrell et al. (1996b) measured peroxy radicals for four one-month intensives.

For a typical midday RO

mixing ratio of 25 pptv the accuracy was ±8–16 pptv for a

1 min average. These data were used to compare with steady state model calculations

based on a large suite of trace gas measurements and other parameters to test for model

Chemical Methods 349

agreement with the measured diurnal cycle. On a number of days the agreement is

quite good. However, on other days the measured values are lower than those calculated

suggesting, as one possibility at least, that peroxy radicals are lost to aerosol surfaces.

Green et al. (2003) report the first use of the PERCA on an aircraft (C130). The perfor-

mance was good (40% uncertainty) provided O

was constant, but O

variability could be

compounded by aircraft speed, causing large variations in the background signal, resulting

in unusable data. Such variability is a common feature of aircraft sampling, but it may

be possible to compensate for it using a dual-inlet approach, with one channel dedicated

to simply measuring the background (Cantrell et al., 1996a), so that the background is

actually measured simultaneous with the peroxy radical signal.

7.9.2 Using reagent NO and SO

, followed by CIMS

detection of H

A new method of chemical amplification and detection was implemented by Reiner et al.

(1997) using sulfur chemistry:

+NO →OH +NO

(7.5)

OH +SO

+M →HOSO

+M (7.16)

HOSO

→ SO

+HO

(7.17)

+2H

O → H

O (7.18)

The initial step in this scheme is the same as in the original, but now the OH is recycled

back to HO

via reaction with SO

(7.16) rather than CO. The SO

is ultimately oxidized

to H

(7.18), which is the detected species. A distinct advantage of this scheme is

the much smaller atmospheric background for H

compared to the NO

detected

in the PERCA scheme. Because the background of the detected species is smaller, less

amplification is required, and the reaction time can be shorter, lessening interferences

and loss processes from, as before, chain terminators like reaction (7.8) and losses to the

walls. Also, since the background is smaller, less measurement uncertainty is introduced

by its variability. The technique also does not suffer the strong H

O dependence of

the PERCA. The H

produced by this amplification scheme is detected by chemical

ionization mass spectrometry (CIMS), a technique already employed in the measurement

of atmospheric H

(Chapter 5). The instrument acronym is ROxMAS (RO

mass

spectrometer) or PerCIMS (peroxy CIMS).

Organic peroxy radicals are also detected in this instrument. For methyl peroxy radical:

+NO →CH

O +NO

(7.19)

O +O

→ HCHO +HO

(7.20)

The HO

so produced (7.20) can then participate in the scheme (7.5, 7.16–7.18).

However, since reactions other than (7.20) are possible for CH

O, the efficiency of

conversion of CH

to H

is somewhat less than that for HO

. This was measured

350 Analytical Techniques for Atmospheric Measurement

in the laboratory and was found to be in the range of 80–100%, depending on reagent gas

concentrations (Reiner et al., 1999). So, the incomplete conversion of this particular RO

species is only modest and not a dominant source of error, so incomplete conversion of

organic peroxy radicals is not a serious problem in the clean atmosphere where CH

will be the dominant one. However, in more polluted environments, other organic peroxy

radicals are present whose conversion is not guaranteed, so there may be increased

measurement uncertainty.

Reiner et al. (1998, 1999) developed an instrument for deployment on an aircraft

(Figure 7.14). Ambient air is forced through the flow reactor by the motion of the aircraft,

so it operates near ambient pressure. The reagent gases, NO and SO

, are added at the

upstream end of the reactor at port RG1 (shown in Figure 7.14). These convert the

peroxy radicals to H

by the time the sample reaches the inlet to the ion-molecule

reaction (IMR) section which operates at a reduced pressure near 100 mb. Here the CIMS

technique is employed to detect H

(Chapter 5). The amplification factor (chain

length) and the ultimate H

concentration are determined by the concentrations of

the reagent gases, but for typical conditions, this factor is about 7, and the lifetime for

against reaction with NO is small, at less than 0.1 s, helping to minimize the effects

of unwanted loss processes. A background signal is obtained by switching the reagent

from RG1 to RG2 (Figure 7.14), while still adding NO at RG1. This allows the

OH +NO termination reaction to occur, but since SO

is still added to the system,

interferent peroxy radicals (e.g. from PAN or HO

 formed downstream of RG2 will

be converted to H

and will contribute to the background determination.

Calibration is achieved using the UV photolysis of H

O at 185 nm, as described in

Section 7.9.1, with care taken to use the effective absorption cross sections characteristic

of the particular system employed. The effects of wall losses were carefully measured on

the ground, and the airborne measurements of peroxy radicals were corrected for these

Figure 7.14 Schematic diagram of an airborne instrument for the measurement of peroxy radicals by

chemical ampliﬁcation, based on the CIMS detection of H

(RO

MAS). (Figure 1 of Reiner et al.,

1998, printed with permission from American Geophysical Union.)

Chemical Methods 351

effects. The accuracy of the airborne measurements is ±40–50%, with the dominant

contribution coming from the 35% uncertainty in the output of the calibration source.

The precision of the measurements under stable in-flight conditions is about 15–20%.

Airborne peroxy radical measurements were made over Germany with values of HO

typically in the range of 10–50 pptv over the 4–8 km altitude range. Additional

measurements of O

, NO, H

O, and the ozone photolysis frequency provided enough

constraints to allow a comparison of the measurements with a simple steady state

model. For a particular flight under clear-sky conditions, good agreement was obtained,

indicating that the production of peroxy radicals was dominated in that case by the

production of OH via O

photolysis followed by O-atom reaction with H

O, and

that radical loss was dominated by self and permutation reactions among peroxy

radicals.

This instrument can also be used to discriminate between HO

and RO

by exploiting

the dependence on O

of the conversion efficiency of RO

species to HO

(7.20), and the

manner in which that conversion to HO

competes with addition reactions of RO

with

NO and of RO with NO and SO

. By switching the buffer gas used to dilute the sample

flow between O

and N

, the O

mixing ratio can be reduced to about 2%, thereby

suppressing the conversion of RO to HO

in (7.20). This gives rise to an approximate

-only mode, whose signal can be subtracted from the usual HO

+RO

mode to

yield a measure of RO

, with careful consideration of conversion efficiencies for the

two modes. Figure 7.15 shows measurements made on a mountaintop in Italy, illus-

trating the diurnal cycles of HO

,RO

, and their sum, with midday values of 30 pptv

for the sum, and with comparable contributions from HO

and RO

(Hanke et al.,

2002). Also shown is the production rate for OH that is calculated from measure-

ments of O

O, and the O

photolysis rate. The observed strong correlation between

the OH production rate and the peroxy radical mixing ratios, even for some short

time scale features, generally results from the fast photochemical equilibrium established

among this set of radicals and serves to confirm aspects of our understanding of this

photochemistry.

Using the same amplification chemistry as Reiner and co-workers, with NO and SO

as reagent gases, Cantrell and coworkers (Edwards et al., 2003) developed a similar

instrument (PerCIMS), also detecting the resultant H

using CIMS. The instrument

also has a mode which discriminates against RO

species, for an HO

-only mode, but it

is achieved differently from ROxMAS. The radical loss reaction

RO +NO +M →RONO +M (7.21)

is made to compete with the HO

-producing reaction (7.20), not by reducing O

, but

by increasing the NO mixing ratio by about two orders of magnitude from the order

of 10 ppmv up to 1000 ppmv or more. Extensive laboratory tests of the discrimination

against RO

species were conducted by measuring the response in the HO

mode (high

NO) to a large variety of RO

radicals generated from these precursors: methane, propane,

butane, isobutane, ethene, propene, cis-butene, trans-butene, isoprene, acetone, benzene,

and toluene. Conversion efficiencies in the HO

mode were generally about 10–15%, and

by modeling the conversion chemistry it was concluded that RO+SO

chemistry is quite

significant in bringing the conversion up from the 2–5% range to the 10–15% range. The

352 Analytical Techniques for Atmospheric Measurement

00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 00

Local time (UTC

+ 2 hr)

Mixing ratio (pptv)

OH production rate

(× 10

)(cm

–3

–1

)

(30 min avg)

∑RO

(30 min avg)

∑RO

(30 min avg)

Figure 7.15 RO

MAS measurements of the diurnal cycle of HO

,RO

, and their sum (upper panel) on

a mountaintop in Italy, along with the calculated OH production rate (lower panel). (Figure 3 of Hanke

et al., 2002, printed with permission from Elsevier.)

conversion efficiencies were also measured in HO

mode and were mostly in the

range of 75–90%. These laboratory tests demonstrate that the PerCIMS instrument should

yield HO

values which are 92–100% of the true amounts. Moreover, by modeling

the RO

partitioning, a correction may be applied for these modest biases. The accuracy

for HO

is ±35% (at 95% confidence), and for HO

it is 41%. The typical precision

is 10%, and the typical detection limit is 1 ×10

−3

for a 15 s average (∼1pptv at

∼500mb). PerCIMS is calibrated using H

O photolysis with N

O actinometry (described

previously).

The PerCIMS measurement of HO

+RO

on a P-3B flying alongside a DC-8 carrying

an LIF instrument for HO

showed generally favorable agreement, with the sum of peroxy

radicals on average being about 2.5 times that of HO

alone, as might be expected for

these conditions, and with a degree of scatter generally consistent with estimated errors.

The PerCIMS instrument has been deployed on aircraft in field campaigns with large

suites of complementary instruments which, via modeling, allow meaningful tests of our

Chemical Methods 353

understanding of the radical chemistry of the atmosphere (Cantrell et al., 2003). For

example, the species that determine the radical production rate are measured, and the

relations among the calculated production rate, the measured HO

+RO

amount, and

have been evaluated and found to be generally consistent with our understanding.

Also, peroxy radical measurements, when combined with measurements of these other

species, enable the calculation of the time rate of change of O

in an air mass. Interestingly

it has also been observed that radical concentrations are reduced in the presence of clouds

(Cantrell et al., 2003), indicating the potential for a significant effect of clouds on oxidant

chemistry.

7.10 Summary and future directions

For several decades these ‘chemical method’ techniques have provided valuable measure-

ments of a wide variety of species, and many of them will continue to do so for the

foreseeable future. However, there are some areas where shortcomings can be identified,

shortcomings that limit advances in our understanding or ability to monitor. An area

where some of these instruments fail to tell the whole story is with respect to speci-

ation within groups of species. For example, the organic peroxy radical measurement by

chemical amplification provides a lumped measure of these species, whereas speciated

measurement of the different RO

would be useful and could be related to measurements

of their source hydrocarbons in the air mass. In the same vein, speciated measurement

of organic peroxides would also be useful. The HPLC techniques described in this

chapter succeed in some cases, but it seems that mixing ratios are often below detection

limits. The same is true for HCHO measurements, which still have large uncertainties

in clean, background air. Likewise, with respect to speciation, the measurement of NO

while valuable, could gainfully be replaced by speciated measurements of the many NO

component species. Progress in this area is being made with use of the CIMS technique

already for HNO

, and speciated PANs (peroxy acyl nitrates). To some extent

this renders the NO

measurement not as useful as it once was; however, it is still

a valuable tracer, especially for those campaigns in which an insufficient number of

component species are measured. Improvements in the photolytic/chemiluminescence

detection of NO

may be on the horizon with the advent of smaller, lighter, less heat-

producing light sources such as LEDs emitting in the 400 nm region (Buhr, 2004).

On the other hand, LIF techniques (Chapter 4) can be an attractive alternative to

photolytic/chemiluminescence detection when NO is a large fraction of NO

(as in the

upper troposphere), because under such conditions the latter technique will always be

limited by the need to calculate NO

as a difference between two relatively large numbers.

As for measurement platforms, the use of in-service aircraft, as by the MOZAIC program,

could be used to assemble expansive climatologies of a variety of species and provide a type

of specialized (not-so-routine) monitoring of the important UT/LS region. All aircraft

data, and especially those from a monitoring program such as MOZAIC, are valuable for

validating the ever-growing suite of satellite measurements, which provide tremendous

information on the broad scale, but which still require in situ aircraft data to aid in their

interpretation.

354 Analytical Techniques for Atmospheric Measurement

Further reading

Chemiluminescence in Analytical Chemistry, edited by Ana M. García-Campaña, Willy R.G. Baeyens,

Marcel Dekker, Inc., 2001.

Handbook of Instrumental Techniques for Analytical Chemistry, edited by Frank A. Settle, Prentice-

Hall, 1997.

R.E. Sievers (1995) Selective Detectors: Environmental, Industrial, and Biomedical Applications, Wiley.

K.C. Clemitshaw (2004) A review of instrumentation and measurement techniques for ground-

based and airborne field studies of gas-phase tropospheric chemistry, Critical Reviews in Environ-

mental Science and Technology, 34, 1–108.

C.A. Cantrell (2003) Observation for chemistry (in situ), chemiluminescent techniques, in Encyclo-

pedia of Atmospheric Sciences, J.R. Holton, J.A. Curry, J.A. Pyle (eds), Academic Press, Vol. 4,

pp. 1454–1460.

References

Air Quality Expert Group (AQEG), M. Pilling, chair (2004) Nitrogen dioxide in the United

Kingdom, http://www.defra.gov.uk/environment/airquality/aqeg.

Ashbourn, S.F.M., Jenkin, M.E., & Clemitshaw, K.C. (1998) Laboratory studies of the response of

a peroxy radical chemical amplifier to HO

and a series of organic peroxy radicals, J. Atmos.

Chem., 29(3), 233–266.

Bernanose, A.J., & René, M.G. (1959) Oxyluminescence of a few fluorescent compounds of ozone,

Advan. Chem. Ser., 21, 7–12.

Bollinger, M.J., Sievers, R.E., Fahey, D.W., & Fehsenfeld, F.C. (1983) Conversion of nitrogen

dioxide, nitric acid, and n-propyl nitrate to nitric oxide by gold-catalyzed reduction with carbon

monoxide, Anal. Chem., 55, 1980–1986.

Bollinger, M.J., Hahn, C.J., Parrish, D.D., Murphy, P.C., Albritton, D.L., & Fehsenfeld, F.C. (1984),

measurements in clean continental air and analysis of the contributing meteorology,

J. Geophys. Res., 89, 9623–9631.

Bowman, R.L., & Alexander, N. (1966) Ozone-induced chemiluminescence of organic compounds,

Science, 154, 1454–1456.

Bradshaw, N.G., Vaughan, G., Busen, R., Garcelon, S., Jones, R., Gardiner, T., & Hacker, J. (2002)

Tracer filamentation generated by small-scale Rossby wave breaking in the lower stratosphere,

J. Geophys. Res., 107(D23), 4689, doi:10.1029/2002JD002086.

Brewer, A.W., & Milford, J.R. (1960) The Oxford-Kew Ozone Sonde, Proc. Roy. Soc. London, Ser.

A, 470–495.

Buhr, M. (2004) Measurement of NO

in ambient air using a solid-state photolytic converter,

Proceedings of the Symposium on Air Quality Measurement Methods and Technology 2004, Air

and Waste Management Association, Research Triangle Park, NC, April 20–24.

Burkhardt, M.R., Maniga, N.I., & Stedman, D.H. (1988) Gas chromatographic method for

measuring nitrogen dioxide and peroxyacetyl nitrate in air without compressed gas cylinders,

Anal. Chem., 60, 816–819.

Cantrell, C.A., & Stedman, D.H. (1982) A possible technique for the measurement of atmospheric

peroxy radicals, Geophys. Res. Lett., 9, 846–849.

Cantrell, C.A., Stedman, D.H., & Wendel, G.J. (1984) Measurement of atmospheric peroxy radicals

by chemical amplification, Anal. Chem., 56, 1496–1502.

Cantrell, C.A., Shetter, R.E., Lind, J.A., McDaniel, A.H., Calvert, J.G., Parrish, D.D., Fehsenfeld,

F.C., Buhr, M.P., & Trainer, M. (1993) An improved chemical amplifier technique for peroxy

radical measurements, J. Geophys. Res., 98, 2897–2909.

Chemical Methods 355

Cantrell, C.A., Shetter, R.E., & Calvert, J.G. (1996a), Dual-inlet chemical amplifier for atmospheric

peroxy radical measurements, Anal. Chem., 68, 4194–4199.

Cantrell, C.A., Shetter, R.E., Gilpin, T.M., Calvert, J.F., Eisele, F.L., & Tanner, D.J. (1996b) Peroxy

radical concentrations measured and calculated from trace gas measurements in the Mauna Loa

Observatory Experiment 2, J. Geophys. Res., 101, 14 653–14 664.

Cantrell, C.A., Zimmer, A., & Tyndall, G.S. (1997) Absorption cross sections for water vapor from

183 to 193 nm, Geophys. Res. Lett., 24(17), 2195–2198.

Cantrell, C.A., et al. (2003) Peroxy radical behavior during the Transport and Chemical Evolution

over the Pacific (TRACE-P) as measured aboard the NASA P-3B aircraft, J. Geophys. Res.,

108(D20), 8797, doi:10.1029/2002JD003674.

Cardenas, L.M., et al. (2000) Intercomparison of formaldehyde measurements in clean and polluted

environments, J. Atmos. Chem., 37, 53–80.

Carroll, M.A., McFarland, M., Ridley, B.A., & Albritton, D.L. (1985) Ground-based nitric oxide

measurements at Wallops Island, Virginia, J. Geophys. Res., 90(D7), 12 853–12 860.

Clemitshaw, K.C., Carpenter, L.J., Penkett, S.A., & Jenkin, M.E. (1997) A calibrated peroxy

radical chemical amplifier for ground-based tropospheric measurements, J. Geophys. Res., 102,

25 405–25 416.

Clough, P.N., & Thrush, B.A. (1967) Mechanism of chemiluminescent reaction between nitric

oxide and ozone, Trans. Faraday Soc., 63, 915–925.

Clyne, M.A.A., Thrush, B.A., & Wayne, R.P. (1964) Kinetics of the chemiluminescent reaction

between nitric oxide and ozone, Trans. Faraday Soc., 60, 359–370.

Creasey, D.J., Heard, D.E., & Lee, J.D. (2000) Absorption cross-section measurements of water

vapour and oxygen at 185 nm. Implications for the calibration of field instruments to measure

OH, HO

and RO

radicals, Geophys. Res. Lett., 27(11), 1651–1654.

Del Negro, L.A., et al. (1999) Comparison of modeled and observed values of NO

and J

during

the Photochemistry of Ozone Loss in the Arctic Region in Summer (POLARIS) mission, J.

Geophys. Res., 104(D21), 26 687–26 703.

Dickerson, R.R., Delany, A.C., & Wartburg, A.F. (1984) Further modification of a commercial NO

detector for high sensitivity, Rev. Sci. Instrum., 55, 1995–1998.

Dong, S., & Dasgupta, P.K. (1987) Fast fluorometric flow injection analysis of formaldehyde in

atmospheric water, Environ. Sci. Technol, 21, 581–588.

Drummond, J.W., Topham, L.A., Mackay, G.I., & Schiff, H.I (1991) Use of chemiluminescence

techniques in portable, lightweight, highly sensitive instruments for measuring NO

,NO

, and

, in Schiff, H.I. (ed.), SPIE, Vol. 1433, Measurement of Atmospheric Gases, 224–231.

Edwards, G.D., Cantrell, C.A., Stephens, S., Hill, B., Goyea, O., Shetter, R.E., Mauldin, R.L.,

Kosciuch, E., Tanner, D.J., & Eisele, F.L. (2003) Chemical ionization mass spectrometer

instrument for the measurement of tropospheric HO

and RO

, Anal. Chem., 75, 5317–5327.

Fahey, D.W., Eubank, C.S., Hübler, G., & Fehsenfeld, F.C. (1985) Evaluation of a catalytic reduction

technique for the measurement of total reactive odd-nitrogen NO

in the atmosphere, J. Atmos.

Chem., 3, 435–468.

Fahey, D.W., et al. (1986) Reactive nitrogen species in the troposphere: Measurements of NO,

, HNO

, particulate nitrate, peroxyacetyl nitrate (PAN), O

, and total reactive odd nitrogen

NO

 at Niwot Ridge, Colorado, J. Geophys. Res., 91, 9781–9793.

Fahey, D.W., et al. (1990) A diagnostic for denitrification in the winter polar stratosphere, Nature,

345, 698–702.

Fahey, D.W., et al. (2001) The detection of large HNO

-containing particles in the winter Arctic

stratosphere, Science, 291, 1026–1031.

Fehsenfeld, F.C., et al. (1987) A ground-based intercomparison of NO, NO

, and NO

measurement

techniques, J. Geophys. Res., 92, 14 710–14 722.

Fehsenfeld, F.C., et al. (1990) Intercomparison of NO

measurement techniques, J. Geophys. Res.,

3579–3597.

356 Analytical Techniques for Atmospheric Measurement

Finlayson, B.J., Pitts, J.N., Jr., & Akimoto, H. (1972) Production of vibrationally excited OH in

chemiluminescent ozone-olefin reactions, Ch. Phys. Lett., 12(3), 495–498.

Fontijn A., Sabadell, A.J., & Ronco, R.J. (1970) Homogeneous chemiluminescent measurement of

nitric oxide with ozone, Anal. Chem., 42, 575–579.

Fried, A., Lee, Y.-N., Frost, G., Wert, B., Henry, B., Drummond, J.R., Hübler, G., & Jobson, T.

(2002) Airborne CH

O measurements over the North Atlantic during the 1997 NARE

campaign: Instrument comparisons and distributions, J. Geophys. Res., 107(D4), 4039,

doi:10.1029/2000JD000260, 2002.

Gao, R.S., Keim, E.R., Woodbridge, E.L., Ciciora, S.J., Proffitt, M.H., Thompson, T.L., McLaughlin,

R.J., & Fahey, D.W. (1994) New photolysis system for NO

measurements in the lower strato-

sphere, J. Geophys. Res., 99(D10), 20 673–20 681.

Gregory, G.L., Hudgins, C.H., & Edahl, R.A. (1983) Laboratory evaluation of an airborne ozone

instrument that compensates for altitude/sensitivity effects, Environ. Sci. Technol., 17, 100–103.

Gregory, G.L., Beck, S.M., & Williams, J.A. (1984) Measurements of free tropospheric ozone: An

aircraft survey from 44



North to 46



South latitude, J. Geophys. Res., 89, 9642–9648.

Green, T.J., Reeves, C.E., Brough, N., Edwards, G.D., Monks, P.S., & Penkett, S.A. (2003) Airborne

measurements of peroxy radicals using the PERCA technique, J. Environ. Monit., 5, 75–83.

Guenther, A.B., & Hills, A.J. (1998) Eddy covariance measurement of isoprene fluxes, J. Geophys.

Res., 103(D11), 13 145–13 152.

Güsten, H., Heinrich, G., Schmidt, R.W.H., & Schurath, U. (1992) A novel ozone sensor for direct

eddy flux measurements, J. Atmos. Chem., 14, 73–84.

Güsten, H., & Heinrich, G. (1996) On-line measurements of ozone surface fluxes: Part I. Method-

ology and instrumentation, Atmos. Environ., 30(6), 897–909.

Handisides, G.M., Plass-Dulmer, C., Gilge, S., Bingemer, H., & Berresheim, H. (2003) Hohen-

peissenberg Photochemical Experiment (HOPE 2000): Measurements and photostationary state

calculations of OH and peroxy radicals, Atmos. Chem. Phys., 3, 1565–1588.

Hanke, M., Uecker, J., Reiner, T., & Arnold, F. (2002) Atmospheric peroxy radicals: ROXMAS, a

new mass-spectrometric methodology for speciated measurements of HO

and RO

and first

results, Int. J. Mass Spectrometry, 213, 91–99.

Harrison, R.M., Peak, J.D., & Collins, G.M. (1996) Tropospheric cycle of nitrous acid, J. Geophys.

Res., 101(D9), 14 429–14 439.

Hastie, D.R., Weissenmayer, M., Burrows, J.P., & Harris, G.W. (1991) Calibrated chemical amplifier

for atmospheric RO

measurements, Anal. Chem., 63, 2048–2057.

Heikes, B.G. (1992) Formaldehyde and hydroperoxides at Mauna Loa Observatory, J. Geophys. Res.,

97, 18 001–18 013.

Helas, G., & Warneck, P. (1981) Background NO

mixing ratios in air masses over the North

Atlantic Ocean, J. Geophys. Res., 86, 7283–7290.

Heland, J., Kleffmann, J., Kurtenbach, R., & Wiesen, P. (2001) A new instrument to measure

gaseous nitrous acid (HONO) in the atmosphere, Environ. Sci. Technol., 35, 3207–3212.

Hills, A.J., & Zimmerman, P.R. (1990) Isoprene measurement by ozone-induced chemilumines-

cence, Anal. Chem., 62, 1055–1060.

Hilsenrath, E., Seiden, L., & Goodman, P. (1969) An ozone measurement in the mesosphere and

stratosphere by means of a rocket sonde, J. Geophys. Res., 74, 6873–6880.

Hilsenrath, E., & Kirschner, P.T. (1980) Recent assessment of the performance and accuracy of a

chemiluminescent rocket sonde for upper atmospheric ozone measurements, Rev. Sci. Instrum.,

51, 1381–1389.

Hofzumahaus, A., et al. (1997) Reply to Lanzendorf et al., Geophys. Res. Lett., 24(23), 3039–3040.

Hodgeson, J.A., Krost, K.J., O’Keeffe, A.E., & Stevens, R.K. (1970) Chemiluminescent measurement

of atmospheric ozone, Anal. Chem., 42, 1795–1802.

Hu, J., & Stedman, D.H. (1994) Free radical detector for tropospheric measurement using chemical

amplification, Anal. Chem., 66, 3384–3393.

Chemical Methods 357

Joseph, D.W., & Spicer, C.W. (1978) Chemiluminescence method for atmospheric monitoring of

nitric acid and nitrogen oxides, Anal. Chem., 50, 1400–1403.

Kelly, T.J., & Stedman, D.H. (1979) Measurements of H

and HNO

in rural air, Geophys. Res.

Lett., 375–378.

Kelly, T.J., Spicer, C.W., & Ward, G.F. (1990) An assessment of the luminol chemiluminescence

technique for measurement of NO

in ambient air, Atmos. Environ., 24A, 2397–2403.

Kley, D., & McFarland, M. (1980) Chemiluminescence detector for NO and NO

, Atmos. Technol.,

12, 63–69.

Kley, D., Drummond, J.W., McFarland, M., & Liu, S.C. (1981) Tropospheric profiles of NO

, J.

Geophys. Res., 86, 3153–3161.

Kliner, D.A.V., Daube, B.C., Burley, J.D., & Wofsy, S.C. (1997), Laboratory investigation of the

catalytic reduction technique for measurement of atmospheric NO

, J. Geophys. Res., 102(D9),

10 759–109 776.

Kok, G.L., Holler, T.P., Lopez, M.B., Nachtrieb, H.A., & Yuan, M. (1978a), Chemiluminescent

method for determination of hydrogen peroxide in the ambient atmosphere, Environ. Sci.

Technol., 12, 1072–1076.

Kok, G.L., Darnall, K.R., Winer, A.M., Pitts, J.N., & Gay, B.W. (1978b) Ambient air measurements

of hydrogen peroxide in the California South Coast Air Basin, Environ. Sci. Technol., 12,

1077–1080.

Komhyr, W.D., Barnes, R.A., Brothers, G.B., Lathrop, J.A., & Opperman, D.P. (1995) Electro-

chemical concentration cell ozonesonde performance evaluation during STOIC 1989, J. Geophys.

Res., 100(D5), 9231–9244.

Kondo, Y., Kojima, H., Toriyama, N., Morita, Y., Takagi, M., & Matthews, W.A. (1987) Chemilu-

minescent ozone instrument for aircraft observation, J. Meteorol. Soc. Japan, 65, 795–802.

Kormann, R., Fischer H., de Reus, M., Lawrence M., Brühl, C., von Kuhlmann, R., Holzinger, R.,

Williams, J., Lelieveld, J., Warneke, C., de Gouw, J., Heland, J., Ziereis, H., & Schlager, H.

(2003) Formaldehyde over the eastern Mediterranean during MINOS: Comparison of airborne

in-situ measurements with 3D-model results, Atmos. Chem. Phys., 3, 851–861.

Lanzendorf, E.J., Hanisco, T.F., Donahue, N.M., & Wennberg, P.O. (1997) Comment on “The

measurement of tropospheric OH radicals by laser-induced fluorescence spectroscopy during

the POPCORN field campaign” by Hofzumahaus et al. and “Intercomparison of tropospheric

OH radical measurements by multiple folded long-path laser absorption and laser induced

fluorescence” by Brauers et al., Geophys. Res. Lett., 24(23), 3037–3038.

Lazrus, A.L., Kok, G.L., Lind, J.A., Gitlin, S.N., Heikes, B.G., & Shetter, R.E. (1986) Automated

fluorometric method for hydrogen peroxide in air, Anal. Chem., 58, 594–597.

Lazrus, A.L., Fong, K.L., & Lind, J.A. (1988) Automated fluorometric determination of

formaldehyde in air, Anal. Chem., 60, 1074–1078.

Lee, M., Noone, B.C., O’Sullivan, D., & Heikes, B.G. (1995) Method for the collection and HPLC

analysis of hydrogen peroxide and C1 and C2 hydroperoxides in the atmosphere, J. Atmos.

Oceanic Technol., 12, 1060–1070.

Lee, Y.-N., Zhou, X., Leaitch, W.R., & Banic, C.M. (1996) An aircraft measurement technique for

formaldehyde and soluble carbonyl compounds, J. Geophys. Res., 101(D22), 29 075–29 080.

Lenschow, D.H., Pearson, R., Jr., & Stankov, B.B. (1981) Estimating the ozone budget in the

boundary layer by use of aircraft measurements of ozone eddy flux and mean concentration,

J. Geophys. Res., 86(C8), 7291–7297.

Logan, J.A. (1999) An analysis of ozonesonde data for the troposphere: Recommendations for

testing 3-D models and development of a gridded climatology for tropospheric ozone, J. Geophys.

Res., 104(D13), 16 115–16 149.

Maeda, Y., Aoki, K., & Munemori, M. (1980) Chemiluminescence method for the determination

of nitrogen dioxide, Anal. Chem., 52, 307–311.