Browsing by Subject "H2SO4"

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  • Lu, Yiqun; Yan, Chao; Fu, Yueyun; Chen, Yan; Liu, Yiliang; Yang, Gan; Wang, Yuwei; Bianchi, Federico; Chu, Biwu; Zhou, Ying; Yin, Rujing; Baalbaki, Rima; Garmash, Olga; Deng, Chenjuan; Wang, Weigang; Liu, Yongchun; Petäjä, Tuukka; Kerminen, Veli-Matti; Jiang, Jingkun; Kulmala, Markku; Wang, Lin (2019)
    Gaseous sulfuric acid (H2SO4) is known as one of the key precursors for atmospheric new particle formation (NPF) processes, but its measurement remains challenging. Therefore, a proxy method that is able to derive gaseous sulfuric acid concentrations from parameters that can be measured relatively easily and accurately is highly desirable for the atmospheric chemistry community. Although such methods are available for clean atmospheric environments, a proxy that works well in a polluted atmosphere, such as that found in Chinese megacities, is yet to be developed. In this study, the gaseous sulfuric acid concentration was measured in February-March 2018, in urban Beijing using a nitrate based -long time-of-flight chemical ionization mass spectrometer (LToF-CIMS). A number of atmospheric parameters were recorded concurrently including the ultraviolet radiation B (UVB) intensity, the concentrations of O-3, NOx (sum of NO and NO2), SO2, and HONO, and aerosol particle number size distributions. A proxy for atmospheric daytime gaseous sulfuric acid concentration was derived via a statistical analysis method using the UVB intensity, [SO2], the condensation sink (CS), [O-3], and [HONO] (or [NOx]) as the predictor variables, where square brackets denote the concentrations of the corresponding species. In this proxy method, we considered the formation of gaseous sulfuric acid from reactions of SO2 and OH radicals during the daytime, and the loss of gaseous sulfuric acid due to its condensation onto the preexisting particles. In addition, we explored the formation of OH radicals from the conventional gas-phase photochemistry using O-3 as a proxy and from the photolysis of HONO using HONO (and subsequently NOx) as a proxy. Our results showed that the UVB intensity and [SO2] are dominant factors in the production of gaseous sulfuric acid, and that the simplest proxy could be constructed with the UVB intensity and [SO2] alone. When the OH radical production from both homogenously and heterogeneously formed precursors were considered, the relative errors were reduced by up to 20 %.
  • Sipilä, M.; Sarnela, N.; Jokinen, T.; Junninen, H.; Hakala, J.; Rissanen, M. P.; Praplan, A.; Simon, M.; Kürten, A.; Bianchi, F.; Dommen, J.; Curtius, J.; Petäjä, T.; Worsnop, D.R. (2015)
    Atmospheric amines may play a crucial role in formation of new aerosol particles via nucleation with sulfuric acid. Recent studies have revealed that concentrations below 1 pptV can significantly promote nucleation of sulfuric acid particles. While sulfuric acid detection is relatively straightforward, no amine measurements to date have been able to reach the critical sub-pptV concentration range and atmospheric amine concentrations are in general poorly characterized. In this work we present a proof-of-concept of an instrument capable of detecting dimethyl amine (DMA) with concentrations even down to 70 ppqV (parts per quadrillion, 0.07 pptV) for a 15 min integration time. Detection of ammonia and amines other than dimethyl amine is discussed. We also report results from the first ambient measurements performed in spring 2013 at a boreal forest site. While minute signals above the signal-to-noise ratio that could be attributed to trimethyl or propyl amine were observed, DMA concentration never exceeded the detection threshold of ambient measurements (150 ppqV), thereby questioning, though not excluding, the role of DMA in nucleation at this location.
  • Frege, Carla; Bianchi, Federico; Molteni, Ugo; Trostl, Jasmin; Junninen, Heikki; Henne, Stephan; Sipilä, Mikko; Herrmann, Erik; Rossi, Michel J.; Kulmala, Markku; Hoyle, Christopher R.; Baltensperger, Urs; Dommen, Josef (2017)
    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 SO5. 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 NH4+ 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 SO5 and CH3SO3- 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 IO3-, 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 I2O5 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.
  • Valadbeigi, Younes; Kurten, Theo (2019)
    The interaction of H2SO4 with boron compounds including BH3, BF3, BCl3, BBr3, B(CN)(3) and B(OH)(3) was studied computationally using the omega B97xD density functional. All the BX3 compounds except B(OH)(3) bind to H2SO4 via both SOH center dot center dot center dot X hydrogen bonds, and interactions between the B atoms and the S=O oxygen atoms. B(OH)(3) interacts with H2SO4 solely through hydrogen bonds. B(CN)(3) and BCl3 exhibit the strongest and weakest interactions with H2SO4, respectively. Natural bond orbital (NBO) analysis shows that the relative weakness of the H2SO4- BCl3 interaction may be due to pi-bonding between the B and Cl atoms, and the occupation of the p(z) orbital of the B atom. The strong electron withdrawing groups CN in B(CN)(3) intensify electron deficiency of B atom and promote its tendency to capture electrons of oxygen atom of O=S group. Atoms in molecules (AIM) calculations show bond critical points (BCP) between the X groups of BX3 and the hydrogen atoms of H2SO4 for all cases except X = OH. Enthalpies and Gibbs free energies of deprotonation in the gas phase (Delta H-acid, Delta G(acid)) were calculated for (BX3)H2SO4 and (BX3)(2)H2SO4 complexes. These data revealed that clustering of BX3 with H2SO4 enhances the acidity of H2SO4 by about 9-58 kcal mol(-1). The (B(CN)(3))(2)H2SO4 cluster had Delta H-acid and Delta G(acid) values of 255.0 and 246.7 kcal mol(-1), respectively, and is the strongest Bronsted acids among the (BX3)(2)H2SO4 clusters.
  • Hansel, Armin; Scholz, Wiebke; Mentler, Bernhard; Fischer, Lukas; Bernd, Torsten (2018)
    The performance of the novel ammonium chemical ionization time of flight mass spectrometer (NH4+-CI3-TOF) utilizing NH4+ adduct ion chemistry to measure first generation oxidized product molecules (OMs) as well as highly oxidized organic molecules (HOMs) was investigated for the first time. The gas-phase ozonolysis of cyclohexene served as a first test system. Experiments have been carried out in the TROPOS free-jet flow system at close to atmospheric conditions. Product ion signals were simultaneously observed by the NH4+-CI3-TOF and the acetate chemical ionization atmospheric pressure interface time of flight mass spectrometer (acetate-CI-APITOF). Both instruments are in remarkable good agreement within a factor of two for HOMs. For OMs not containing an OOH group the acetate technique can considerably underestimate OM concentrations by 2-3 orders of magnitude. First steps of cyclohexene ozonolysis generate ten different main products, detected with the ammonium-CI3-TOF, comprising 93% of observed OMs. The remaining 7% are distributed over several minor products that can be attributed to HOMs, predominately to highly oxidized RO2 radicals. Summing up, observed ammonium-CI3-TOF products yield 5.6 x le molecules cm" in excellent agreement with the amount of reacted cyclohexene of 4.5 x 10(9) molecules cm(-3) for reactant concentrations of [O-3] = 2.25 x 10(12) molecules cm(-3) and [cyclohexene] = 2.0 x 10(12) molecules cm(-3) and a reaction time of 7.9 s. NH4+ adduct ion chemistry is a promising CIMS technology for achieving carbon-closure due to the unique opportunity for complete detection of the whole product distribution including also peroxy radicals, and consequently, for a much better understanding of oxidation processes.
  • Neitola, Kimmo; Brus, David; Makkonen, Ulla; Sipila, Mikko; Lihavainen, Heikki; Kulmala, Markku (2014)
  • Kuerten, Andreas; Bianchi, Federico; Almeida, Joao; Kupiainen-Määttä, Oona; Dunne, Eimear M.; Duplissy, Jonathan; Williamson, Christina; Barmet, Peter; Breitenlechner, Martin; Dommen, Josef; Donahue, Neil M.; Flagan, Richard C.; Franchin, Alessandro; Gordon, Hamish; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Ickes, Luisa; Jokinen, Tuija; Kangasluoma, Juha; Kim, Jaeseok; Kirkby, Jasper; Kupc, Agnieszka; Lehtipalo, Katrianne; Leiminger, Markus; Makhmutov, Vladimir; Onnela, Antti; Ortega, Ismael K.; Petäjä, Tuukka; Praplan, Arnaud P.; Riccobono, Francesco; Rissanen, Matti P.; Rondo, Linda; Schnitzhofer, Ralf; Schobesberger, Siegfried; Smith, James N.; Steiner, Gerhard; Stozhkov, Yuri; Tome, Antonio; Trostl, Jasmin; Tsagkogeorgas, Georgios; Wagner, Paul E.; Wimmer, Daniela; Ye, Penglin; Baltensperger, Urs; Carslaw, Ken; Kulmala, Markku; Curtius, Joachim (2016)
    Binary nucleation of sulfuric acid and water as well as ternary nucleation involving ammonia are thought to be the dominant processes responsible for new particle formation (NPF) in the cold temperatures of the middle and upper troposphere. Ions are also thought to be important for particle nucleation in these regions. However, global models presently lack experimentally measured NPF rates under controlled laboratory conditions and so at present must rely on theoretical or empirical parameterizations. Here with data obtained in the European Organization for Nuclear Research CLOUD (Cosmics Leaving OUtdoor Droplets) chamber, we present the first experimental survey of NPF rates spanning free tropospheric conditions. The conditions during nucleation cover a temperature range from 208 to 298K, sulfuric acid concentrations between 5x10(5) and 1x10(9)cm(-3), and ammonia mixing ratios from zero added ammonia, i.e., nominally pure binary, to a maximum of -1400 parts per trillion by volume (pptv). We performed nucleation studies under pure neutral conditions with zero ions being present in the chamber and at ionization rates of up to 75ion pairs cm(-3)s(-1) to study neutral and ion-induced nucleation. We found that the contribution from ion-induced nucleation is small at temperatures between 208 and 248K when ammonia is present at several pptv or higher. However, the presence of charges significantly enhances the nucleation rates, especially at 248K with zero added ammonia, and for higher temperatures independent of NH3 levels. We compare these experimental data with calculated cluster formation rates from the Atmospheric Cluster Dynamics Code with cluster evaporation rates obtained from quantum chemistry.
  • Berndt, Torsten; Richters, Stefanie; Jokinen, Tuija; Hyttinen, Noora; Kurten, Theo; Otkjaer, Rasmus V.; Kjaergaard, Henrik G.; Stratmann, Frank; Herrmann, Hartmut; Sipilä, Mikko; Kulmala, Markku; Ehn, Mikael (2016)
    Explaining the formation of secondary organic aerosol is an intriguing question in atmospheric sciences because of its importance for Earth's radiation budget and the associated effects on health and ecosystems. A breakthrough was recently achieved in the understanding of secondary organic aerosol formation from ozone reactions of biogenic emissions by the rapid formation of highly oxidized multifunctional organic compounds via autoxidation. However, the important daytime hydroxyl radical reactions have been considered to be less important in this process. Here we report measurements on the reaction of hydroxyl radicals with alpha- and beta- pinene applying improved mass spectrometric methods. Our laboratory results prove that the formation of highly oxidized products from hydroxyl radical reactions proceeds with considerably higher yields than previously reported. Field measurements support these findings. Our results allow for a better description of the diurnal behaviour of the highly oxidized product formation and subsequent secondary organic aerosol formation in the atmosphere.
  • Jokinen, T.; Sipilä, M.; Kontkanen, J.; Vakkari, V.; Tisler, P.; Duplissy, E.-M.; Junninen, H.; Kangasluoma, J.; Manninen, H. E.; Petäjä, T.; Kulmala, M.; Worsnop, D. R.; Kirkby, J.; Virkkula, A.; Kerminen, V.-M. (2018)
    Formation of new aerosol particles from trace gases is a major source of cloud condensation nuclei (CCN) in the global atmosphere, with potentially large effects on cloud optical properties and Earth's radiative balance. Controlled laboratory experiments have resolved, in detail, the different nucleation pathways likely responsible for atmospheric new particle formation, yet very little is known from field studies about the molecular steps and compounds involved in different regions of the atmosphere. The scarcity of primary particle sources makes secondary aerosol formation particularly important in the Antarctic atmosphere. Here, we report on the observation of ion-induced nucleation of sulfuric acid and ammonia-a process experimentally investigated by the CERN CLOUD experiment-as a major source of secondary aerosol particles over coastal Antarctica. We further show that measured high sulfuric acid concentrations, exceeding 10(7) molecules cm(-3), are sufficient to explain the observed new particle growth rates. Our findings show that ion-induced nucleation is the dominant particle formation mechanism, implying that galactic cosmic radiation plays a key role in new particle formation in the pristine Antarctic atmosphere.
  • Xiao, S.; Wang, M. Y.; Yao, L.; Kulmala, M.; Zhou, B.; Yang, X.; Chen, J. M.; Wang, D. F.; Fu, Q. Y.; Worsnop, D. R.; Wang, L. (2015)
  • Neitola, K.; Brus, D.; Makkonen, U.; Sipilä, Mikko; Mauldin III, Roy; Sarnela, N.; Jokinen, T.; Lihavainen, H.; Kulmala, Markku (2015)
    Sulfuric acid is known to be a key component for atmospheric nucleation. Precise determination of sulfuric-acid concentration is a crucial factor for prediction of nucleation rates and subsequent growth. In our study, we have noticed a substantial discrepancy between sulfuric-acid monomer concentrations and total-sulfate concentrations measured from the same source of sulfuric-acid vapor. The discrepancy of about 1-2 orders of magnitude was found with similar particle-formation rates. To investigate this discrepancy, and its effect on nucleation, a method of thermally controlled saturator filled with pure sulfuric acid (97% wt.) for production of sulfuric-acid vapor is applied and rigorously tested. The saturator provided an independent vapor-production method, compared to our previous method of the furnace (Brus et al., 2010, 2011), to find out if the discrepancy is caused by the production method itself. The saturator was used in a H2SO4-H2O nucleation experiment, using a laminar flow tube to check reproducibility of the nucleation results with the saturator method, compared to the furnace. Two independent methods of mass spectrometry and online ion chromatography were used for detecting sulfuric-acid or sulfate concentrations. Measured sulfuric-acid or total-sulfate concentrations are compared to theoretical predictions calculated using vapor pressure and a mixing law. The calculated prediction of sulfuric-acid concentrations agrees very well with the measured values when total sulfate is considered. Sulfuric-acid monomer concentration was found to be about 2 orders of magnitude lower than theoretical predictions, but with a temperature dependency similar to the predictions and the results obtained with the ion-chromatograph method. Formation rates are reproducible when compared to our previous results with both sulfuric-acid or total-sulfate detection and sulfuric-acid production methods separately, removing any doubts that the vapor-production method would cause the discrepancy. Possible reasons for the discrepancy are discussed and some suggestions include that the missing sulfuric acid is in clusters, formed with contaminants found in most laboratory experiments. One-to-two-order-of-magnitude higher sulfuric-acid concentrations (measured as total sulfate in this study) would contribute to a higher fraction of particle growth rate than assumed from the measurements by mass spectrometers (i.e. sulfuric-acid monomer). However, the observed growth rates by sulfate-containing vapor in this study does not directly imply a similar situation in the field, where sources of sulfate are much more diverse.