Effect of relative humidity on the detection of sulfur dioxide and sulfuric acid using a chemical ionization mass spectrometer

Salcedo, D.; Villalta, Peter W.; Varutbangkul, Varuntida; Wormhoudt, J.; Miake-Lye, Richard C.; Worsnop, Douglas R.; Ballenthin, J. O.; Thorn, W. F.; Viggiano, A. A.; Miller, Thomas M.; Flagan, R. C.; Seinfeld, John H.

doi:10.1016/j.ijms.2003.09.005

Cited by 22 publications

(15 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These included I − , IO − , IO − 2 , and clusters of I 2 O 3 and I 2 O 5 with ions of sulfuric acid or MSA (e.g., I 2 O 5 q CH 3 SO − 3 ). The observation of I 2 O 5 in clusters with CH 3 SO − 3 and sulfuric acid confirms the presence of I 2 O 5 in the atmosphere which was proposed from laboratory and modeling studies (Saunders and Plane, 2005). However, to our knowledge no studies have reported the presence of I 2 O 5 in the atmosphere up to now.…”

Section: Iodine Speciessupporting

confidence: 86%

Answers to Referee 3

Frege¹

2016

View full text Add to dashboard Cite

The ion composition at high altitude (3454 m a.s.l.) was measured with an atmospheric pressure interface time-of-flight mass spectrometer (APi-TOF) during a period of 9 months, from August 2013 to April 2014. The negative mass spectra were dominated by the ions of sulfuric, nitric, malonic, and methanesulfonic acid (MSA) as well as SO − 5 . The most prominent positive ion peaks were from amines. The other cations were mainly organic compounds clustered with a nitrogen-containing ion, which could be either NH + 4 or an aminium. Occasionally the positive spectra were characterized by groups of compounds each differing by a methylene group. In the negative spectrum, sulfuric acid was always observed during clear sky conditions following the diurnal cycle of solar irradiation. On many occasions we also saw a high signal of sulfuric acid during nighttime when clusters up to the tetramer were observed. A plausible reason for these events could be evaporation from particles at low relative humidity. A remarkably strong correlation between the signals of SO − 5 and CH 3 SO − 3 was observed for the full measurement period. The presence of these two ions during both the day and the night suggests a non-photochemical channel of formation which is possibly linked to halogen chemistry. Halogenated species, especially Br − and IO − 3 , were frequently observed in air masses that originated mainly from the Atlantic Ocean and occasionally from continental areas based on back trajectory analyses. We found I 2 O 5 clustered with an ion, a species that was proposed from laboratory and modeling studies. All halogenated ions exhibited an unexpected diurnal behavior with low values during daytime. New particle formation (NPF) events were observed and characterized by (1) highly oxygenated molecules (HOMs) and low sulfuric acid or (2) ammonia-sulfuric acid clusters. We present characteristic spectra for each of these two event types based on 26 nucleation episodes. The mass spectrum of the ammonia-sulfuric acid nucleation event compares very well with laboratory measurements reported from the CLOUD chamber. A source receptor analysis indicates that NPF events at the Jungfraujoch take place within a restricted period of time of 24-48 h after air masses have had contact with the boundary layer. This time frame appears to be crucial to reach an optimal oxidation state and concentration of organic molecules necessary to facilitate nucleation.

show abstract

Section: Iodine Speciessupporting

confidence: 86%

Answers to Referee 3

Frege¹

2016

View full text Add to dashboard Cite

show abstract

“…According to classical theory of hydration made by Jaecker-Voirol and Mirabel (1988), JaeckerVoirol et al (1987) and validated by Kulmala et al (1991), only about 10 % of sulfuric acid is in unhydrated form at relative humidity of 50 %. Salcedo et al (2004) studied the effect of relative humidity on the detection of sulfur dioxide and sulfuric acid and found negative effect on the sensitivity of the CIMS to SO 2 and H 2 SO 4 because water molecules form clusters with reactant and product ions thus shielding the molecules from being ionized. They claim that the effect can be avoided by increasing the CIMS' inlet flow tube temperature to 150 • C. On the other hand e.g.…”

Section: Comparison To Our Previous Datamentioning

confidence: 99%

Homogenous nucleation of sulfuric acid and water at close to atmospherically relevant conditions

et al. 2011

View full text Add to dashboard Cite

Abstract. In this study the homogeneous nucleation rates in the system of sulfuric acid and water were measured by using a flow tube technique. The goal was to directly compare particle formation rates obtained from atmospheric measurements with nucleation rates of freshly nucleated particles measured with particle size magnifier (PSM) which has detection efficiency of unity for particles having mobility diameter of 1.5 nm. The gas phase sulfuric acid concentration in this study was measured with the chemical ionization mass spectrometer (CIMS), commonly used in field measurements. The wall losses of sulfuric acid were estimated from measured concentration profiles along the flow tube. The initial concentrations of sulfuric acid estimated from loss measurements ranged from 10 8 to 3 × 10 9 molecules cm −3 . The nucleation rates obtained in this study cover about three orders of magnitude from 10 −1 to 10 2 cm −3 s −1 for commercial ultrafine condensation particle counter (UCPC) TSI model 3025A and from 10 1 to 10 4 cm −3 s −1 for PSM. The nucleation rates and the slopes (dlnJ/dln [H 2 SO 4 ]) show satisfactory agreement when compared to empirical kinetic and activation models and the latest atmospheric nucleation data. To the best of our knowledge, this is the first experimental work providing temperature dependent nucleation rate measurements using a high efficiency particle counter with a cutoff-size of 1.5 nm together with direct measurements of gas phase sulfuric acid concentration.

show abstract

“…The peak intensities of SF 4 Figure 2(b) shows that the intensity of the OH peak decreased with the addition of water into the flow tube system, which was due to not only the loss of CIMS sensitivity as described above, but also to the conversion of OH into OH-water complexes. [17][18][19][20] In particular, the peak intensity of [OH(…”

Section: Resultsmentioning

confidence: 99%

Experimental Study on the Interference of Water Vapor on the Chemical Ionization of OH by Sulfur Hexafluoride Ion

Park¹

2014

Mass Spectrometry Letters

View full text Add to dashboard Cite

The interference of water vapor on the chemical ionization (CI) of hydroxyl radicals (OH) by sulfur hexafluoride ion (SF 6 -) was investigated using a flow tube system coupled to a high-pressure CI mass spectrometer. Water vapor, which is required to study heterogeneous reactions of OH under real tropospheric conditions, transforms the reagent ion SF ) and water molecules. An additional helium buffer flow introduced into the CI region reduced loss of the reagent ion and resulted in a partial recovery of OH peak intensities under humid conditions.

show abstract

Effect of relative humidity on the detection of sulfur dioxide and sulfuric acid using a chemical ionization mass spectrometer

Cited by 22 publications

References 31 publications

Answers to Referee 3

Answers to Referee 3

Homogenous nucleation of sulfuric acid and water at close to atmospherically relevant conditions

Experimental Study on the Interference of Water Vapor on the Chemical Ionization of OH by Sulfur Hexafluoride Ion

Contact Info

Product

Resources

About