scholarly journals Observation of new particle formation and measurement of sulfuric acid, ammonia, amines and highly oxidized molecules using nitrate CI-APi-TOF at a rural site in central Germany

2016 ◽  
Author(s):  
Andreas Kürten ◽  
Anton Bergen ◽  
Martin Heinritzi ◽  
Markus Leiminger ◽  
Verena Lorenz ◽  
...  

Abstract. The exact mechanisms for new particle formation (NPF) under different boundary layer conditions are not known yet. One important question is if amines and sulfuric acid lead to efficient NPF in the atmosphere. Furthermore, it is not clear to what extent highly oxidized organic molecules (HOM) are involved in NPF. We conducted field measurements at a rural site in central Germany in the proximity of three larger dairy farms to investigate if there is a connection between NPF and the presence of amines and/or ammonia due to the local emissions from the farms. Comprehensive measurements using a nitrate Chemical Ionization-Atmospheric Pressure interface-Time Of Flight (CI-APi-TOF) mass spectrometer, a Proton Transfer Reaction-Mass Spectrometer (PTR-MS), particle counters and Differential Mobility Analyzers (DMAs) as well as measurements of trace gases and meteorological parameters were performed. It is shown that the nitrate CI-APi-TOF is suitable for sensitive measurements of sulfuric acid, amines, a nitrosamine, ammonia, iodic acid and HOM. NPF was found to correlate with sulfuric acid, while an anti-correlation with RH, amines and ammonia is observed. The anti-correlation between NPF and amines could be due to the efficient uptake of these compounds by nucleating clusters and small particles. Much higher HOM dimer (C19/C20 compounds) concentrations during the night than during the day indicate that these HOM do not efficiently self-nucleate as no night-time NPF is observed. Observed iodic acid probably originates from an iodine-containing reservoir substance but the iodine signals are very likely too low to have a significant effect on NPF.

2016 ◽  
Vol 16 (19) ◽  
pp. 12793-12813 ◽  
Author(s):  
Andreas Kürten ◽  
Anton Bergen ◽  
Martin Heinritzi ◽  
Markus Leiminger ◽  
Verena Lorenz ◽  
...  

Abstract. The exact mechanisms for new particle formation (NPF) under different boundary layer conditions are not known yet. One important question is whether amines and sulfuric acid lead to efficient NPF in the atmosphere. Furthermore, it is not clear to what extent highly oxidized organic molecules (HOMs) are involved in NPF. We conducted field measurements at a rural site in central Germany in the proximity of three larger dairy farms to investigate whether there is a connection between NPF and the presence of amines and/or ammonia due to the local emissions from the farms. Comprehensive measurements using a nitrate chemical ionization–atmospheric pressure interface time-of-flight (CI-APi-TOF) mass spectrometer, a proton-transfer-reaction mass spectrometer (PTR-MS), particle counters and differential mobility analyzers (DMAs), as well as measurements of trace gases and meteorological parameters, were performed. We demonstrate here that the nitrate CI-APi-TOF is suitable for sensitive measurements of sulfuric acid, amines, a nitrosamine, ammonia, iodic acid and HOMs. NPF was found to correlate with sulfuric acid, while an anti-correlation with RH, amines and ammonia is observed. The anti-correlation between NPF and amines could be due to the efficient uptake of these compounds by nucleating clusters and small particles. Much higher HOM dimer (C19/C20 compounds) concentrations during the night than during the day indicate that these HOMs do not efficiently self-nucleate as no nighttime NPF is observed. Observed iodic acid probably originates from an iodine-containing reservoir substance, but the iodine signals are very likely too low to have a significant effect on NPF.


2021 ◽  
Author(s):  
Tuija Jokinen ◽  
Katrianne Lehtipalo ◽  
Kimmo Neitola ◽  
Nina Sarnela ◽  
Totti Laitinen ◽  
...  

<p>One way to form aerosol particles is the condensation of oxidized atmospheric trace gases, such as sulfuric acid (SA) into small molecular clusters. After growing to larger particles by condensation of low volatile gases, they can affect the planets climate directly by scattering light and indirectly by acting as cloud condensation nuclei. Observations of low-volatility aerosol precursor gases have been reported around the world but long-term measurement series and Arctic data sets showing seasonal variation are close to non-existent. In here, we present ~7 months of aerosol precursor gas measurements performed with the nitrate based chemical ionization mass spectrometer (CI-APi-TOF). We deployed our measurements ~250 km above the Arctic Circle at the Finnish sub-Arctic field station, SMEAR I in Värriö. We report concentration measurements of the most common new particle formation related compounds; sulfuric acid, methanesulfonic acid (MSA), iodic acid (IA) and highly oxygenated organic compounds, HOMs. At this remote measurement site, surrounded by a strict nature preserve, that gets occasional pollution from a Russian city of Murmansk, SA is originated both from anthropogenic and biological sources and has a clear diurnal cycle but no significant seasonal variation, while MSA as an oxidation product of purely biogenic sources is showing a more distinct seasonal cycle. Iodic acid concentrations are the most stable throughout the measurement period, showing almost identical peak concentrations for spring, summer and autumn. HOMs are abundant during the summer months and due to their high correlation with ambient air temperature, we suggest that most of HOMs are products of monoterpene oxidation. New particle formation events at SMEAR I happen under relatively low temperatures, low relative humidity, high ozone concentration, high SA concentration in the morning and high MSA concentrations in the afternoon. The role of HOMs in aerosol formation will be discussed. All together, these are the first long term measurements of aerosol forming precursor from the sub-arctic region helping us to understand atmospheric chemical processes and aerosol formation in the rapidly changing Arctic.</p><p> </p><p> </p>


2021 ◽  
Author(s):  
Roseline Thakur ◽  
Lubna Dada ◽  
Lisa Beck ◽  
Tommy Chan ◽  
Juha Sulo ◽  
...  

<p>Aerosols can originate from different sources and undergo various formation pathways. New Particle formation (NPF) events occur when precursor vapors nucleate and vapors with low volatility condense on the critical nuclei enabling them to grow to cloud condensation nuclei (CCN) relevant sizes. As CCN, these aerosols affect the occurrence of clouds and their lifetime on local, regional and global level.  Many studies have investigated new particle formation events from various sites ranging from urban areas, boreal forests to pristine locations; however, there is still a dearth of studies investigating coastal new particle formation, which is a complex phenomenon due to the dynamic and ever-changing atmospheric conditions at the coast.  A comprehensive study of particle number distributions and aerosol forming precursor vapors was carried out in a coastal capital city of Finland, Helsinki, during the summer of 2019. The experimental setup comprising of a nitrate-based chemical ionization atmospheric pressure interface time of flight mass spectrometer (CI-APi-TOF), a neutral cluster-air ion spectrometer (NAIS) and a particle size magnifier (PSM) were housed in and around the SMEAR III station in Kumpula Science campus. SMEAR III is a unique site situated in a semi-urban yet coastal location. The period of experiment coincided with the cyanobacterial bloom in the coastal areas of Finland and in the Baltic Sea region. Our study recorded several regional NPF and aerosol burst events during this period. High concentrations of sulfuric acid was found to be associated with the regional NPF events whereas increasing iodic acid concentrations was mostly associated with the initiation of burst events. The sources of sulfuric acid and iodic acid has been carefully evaluated in this study.</p><p> </p>


2014 ◽  
Vol 7 (11) ◽  
pp. 3849-3859 ◽  
Author(s):  
L. Rondo ◽  
A. Kürten ◽  
S. Ehrhart ◽  
S. Schobesberger ◽  
A. Franchin ◽  
...  

Abstract. Ternary aerosol nucleation experiments were conducted in the CLOUD chamber at CERN in order to investigate the influence of ions on new particle formation. Neutral and ion-induced nucleation experiments, i.e. without and with the presence of ions, respectively, were carried out under precisely controlled conditions. The sulfuric acid concentration was measured with a chemical ionisation mass spectrometer (CIMS) during the new particle formation experiments. The added ternary trace gases were ammonia (NH3), dimethylamine (DMA, C2H7N) or oxidised products of pinanediol (PD, C10H18O2). When pinanediol was introduced into the chamber, an increase in the mass spectrometric signal used to determine the sulfuric acid concentration (m/z 97, i.e. HSO4−) was observed due to ions from the CLOUD chamber. The enhancement was only observed during ion-induced nucleation measurements by using either galactic cosmic rays (GCRs) or the proton synchrotron (PS) pion beam for the ion generation, respectively. The ion effect typically involved an increase in the apparent sulfuric acid concentration by a factor of ~ 2 to 3 and was qualitatively verified by the ion measurements with an atmospheric-pressure interface-time of flight (APi-TOF) mass spectrometer. By applying a high-voltage (HV) clearing field inside the CLOUD chamber, the ion effect on the CIMS measurement was completely eliminated since, under these conditions, small ions are swept from the chamber in about 1 s. In order to exclude the ion effect and to provide corrected sulfuric acid concentrations during the GCR and PS beam nucleation experiments, a parameterisation was derived that utilises the trace gas concentrations and the UV light intensity as input parameters. Atmospheric sulfuric acid measurements with a CIMS showed an insignificant ion effect.


2016 ◽  
Author(s):  
Carla Frege ◽  
Federico Bianchi ◽  
Ugo Molteni ◽  
Jasmin Tröstl ◽  
Heikki Junninen ◽  
...  

Abstract. The ion composition at high-altitude (3450 m a.s.l.) was measured with an Atmospheric Pressure interface Time of Flight mass spectrometer (APi-TOF) during a period of nine months. 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 sun irradiation. We also measured many events during night time where the signal of sulfuric acid was high and 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 measured I2O5 clustered with an ion, a species that was proposed from laboratory and modelling studies. All halogenated species exhibited an unexpected diurnal behaviour with low values during day time. 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 new particle formation events at the Jungfraujoch take place within a restricted period of time of 24–48 hours after air masses have had contact with boundary layer. This time frame appears to be crucial to reach an optimal oxidation state and concentration of organic molecules necessary to facilitate nucleation.


2021 ◽  
Author(s):  
James Brean ◽  
Manuel Dall’Osto ◽  
Rafel Simó ◽  
Zongbo Shi ◽  
David C. S. Beddows ◽  
...  

2018 ◽  
Vol 18 (16) ◽  
pp. 11779-11791 ◽  
Author(s):  
Ximeng Qi ◽  
Aijun Ding ◽  
Pontus Roldin ◽  
Zhengning Xu ◽  
Putian Zhou ◽  
...  

Abstract. Highly oxygenated multifunctional compounds (HOMs) play a key role in new particle formation (NPF), but their quantitative roles in different environments of the globe have not been well studied yet. Frequent NPF events were observed at two “flagship” stations under different environmental conditions, i.e. a remote boreal forest site (SMEAR II) in Finland and a suburban site (SORPES) in polluted eastern China. The averaged formation rate of 6 nm particles and the growth rate of 6–30 nm particles were 0.3 cm−3 s−1 and 4.5 nm h−1 at SMEAR II compared to 2.3 cm−3 s−1 and 8.7 nm h−1 at SORPES, respectively. To explore the differences of NPF at the two stations, the HOM concentrations and NPF events at two sites were simulated with the MALTE-BOX model, and their roles in NPF and particle growth in the two distinctly different environments are discussed. The model provides an acceptable agreement between the simulated and measured concentrations of sulfuric acid and HOMs at SMEAR II. The sulfuric acid and HOM organonitrate concentrations are significantly higher but other HOM monomers and dimers from monoterpene oxidation are lower at SORPES compared to SMEAR II. The model simulates the NPF events at SMEAR II with a good agreement but underestimates the growth of new particles at SORPES, indicating a dominant role of anthropogenic processes in the polluted environment. HOMs from monoterpene oxidation dominate the growth of ultrafine particles at SMEAR II while sulfuric acid and HOMs from aromatics oxidation play a more important role in particle growth. This study highlights the distinct roles of sulfuric acid and HOMs in NPF and particle growth in different environmental conditions and suggests the need for molecular-scale measurements in improving the understanding of NPF mechanisms in polluted areas like eastern China.


2007 ◽  
Vol 7 (1) ◽  
pp. 211-222 ◽  
Author(s):  
M. Ehn ◽  
T. Petäjä ◽  
H. Aufmhoff ◽  
P. Aalto ◽  
K. Hämeri ◽  
...  

Abstract. The hygroscopic growth of aerosol particles present in a boreal forest was measured at a relative humidity of 88%. Simultaneously the gas phase concentration of sulfuric acid, a very hygroscopic compound, was monitored. The focus was mainly on days with new particle formation by nucleation. The measured hygroscopic growth factors (GF) correlated positively with the gaseous phase sulfuric acid concentrations. The smaller the particles, the stronger the correlation, with r=0.20 for 50 nm and r=0.50 for 10 nm particles. The increase in GF due to condensing sulfuric acid is expected to be larger for particles with initially smaller masses. During new particle formation, the changes in solubility of the new particles were calculated during their growth to Aitken mode sizes. As the modal diameter increased, the solubility of the particles decreased. This indicated that the initial particle growth was due to more hygroscopic compounds, whereas the later growth during the evening and night was mainly caused by less hygroscopic or even hydrophobic compounds. For all the measured sizes, a diurnal variation in GF was observed both during days with and without particle formation. The GF was lowest at around midnight, with a mean value of 1.12–1.24 depending on particle size and if new particle formation occurred during the day, and increased to 1.25–1.34 around noon. This can be tentatively explained by day- and nighttime gas-phase chemistry; different vapors will be present depending on the time of day, and through condensation these compounds will alter the hygroscopic properties of the particles in different ways.


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