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Markku Kulmala - One of the best experts on this subject based on the ideXlab platform.
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Total sulphate vs. Sulphuric Acid monomer in nucleation studies
Atmospheric Chemistry and Physics, 2014Co-Authors: K. Neitola, David Brus, Ulla Makkonen, Mikko Sipilä, Roy L. Mauldin, Nina Sarnela, Tuija Jokinen, Heikki Lihavainen, Markku KulmalaAbstract:Abstract. Sulphuric Acid is known to be a key component for atmospheric nucleation. Precise determination of Sulphuric Acid concentration is crucial factor for prediction of nucleation rates and subsequent growth. In our study, we have noticed a substantial discrepancy between Sulphuric Acid monomer and total sulphate concentrations measured from the same source of Sulphuric Acid vapour. The discrepancy of about one to two orders of magnitude was found with similar formation rates. To investigate this discrepancy and its effect on nucleation, a method of thermally controlled saturator filled with pure Sulphuric Acid (97% wt.) for production of Sulphuric Acid vapour is introduced and tested. Sulphuric Acid-water nucleation experiment was done using a laminar flow tube. Two independent methods of mass spectrometry and online ion chromatography were used for detecting Sulphuric Acid concentrations. The results are compared to our previous results, where a method of furnace was used to produce Sulphuric Acid vapour (Brus et al., 2010, 2011). Measured Sulphuric Acid concentrations are compared to theoretical prediction calculated using vapour pressure and a mixing law. The calculated prediction of Sulphuric Acid concentrations agrees very well with the measured values when total sulphate is considered. Sulphuric Acid monomer concentration was found to be about two orders of magnitude lower than the prediction, but with similar temperature dependency as the prediction and the results obtained with ion chromatograph method. Formation rates agree well when compared to our previous results with both Sulphuric Acid detection and Sulphuric Acid production methods separately.
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Total sulphate vs. Sulphuric Acid monomer in nucleation studies: which represents the "true" concentration?
Atmospheric Chemistry and Physics, 2013Co-Authors: K. Neitola, David Brus, Ulla Makkonen, Mikko Sipilä, Roy L. Mauldin, Heikki Lihavainen, Katriina Kyllönen, Markku KulmalaAbstract:Abstract. Sulphuric Acid is known to be a key component for atmospheric nucleation. Precise determination of Sulphuric Acid concentration is crucial factor for prediction of nucleation rates and subsequent growth. In our study, we have noticed a substantial discrepancy between Sulphuric Acid monomer and total sulphate concentrations measured from the same source of Sulphuric Acid vapour. The discrepancy of about one to two orders of magnitude was found with similar formation rates. The reason for this difference is not yet clear and it can have great impact on predicting atmospheric nucleation rates as well as growth rates. To investigate this discrepancy and its effect on nucleation, a method of thermally controlled saturator filled with pure Sulphuric Acid (~97%) for production of Sulphuric Acid vapour is introduced and tested. Sulphuric Acid-water nucleation experiment was done using a laminar flow tube. Two independent methods of mass spectrometry and online ion chromatography were used for detecting Sulphuric Acid concentrations. The results are compared to our previous results, where a method of evaporating weak Sulphuric Acid-water solution droplets in a furnace was used to produce Sulphuric Acid vapour (Brus et al., 2010, 2011). Measured Sulphuric Acid concentrations are compared to theoretical prediction calculated using vapour pressure and simple mixing law. The calculated prediction of Sulphuric Acid concentrations agrees very well with the measured values when total sulphate is considered. Sulphuric Acid monomer concentration was found to be about two orders of magnitude lower than the prediction, but with similar temperature dependency as the prediction and the results obtained with ion chromatograph method. Formation rates agree well when compared to our previous results with both Sulphuric Acid detection and Sulphuric Acid production methods separately.
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atmospheric Sulphuric Acid and neutral cluster measurements using ci api tof
Atmospheric Chemistry and Physics, 2011Co-Authors: Tuija Jokinen, Tuukka Petaja, Mikko Sipilä, Markku Kulmala, Heikki Junninen, Gustaf Lonn, Jani Hakala, R L Mauldin, D R WorsnopAbstract:Abstract. The first ambient measurements using nitrate ion based Chemical Ionization with the Atmospheric Pressure interface Time-Of-Flight mass spectrometer (CI-APi-TOF) for Sulphuric Acid and neutral cluster detection are presented. We have found CI-APi-TOF a highly stable and sensitive tool for molecular Sulphuric Acid detection. The lowest limit of detection for Sulphuric Acid was determined to be 3.6 × 10 4 molecules cm −3 for 15 min averaging. Signals from Sulphuric Acid clusters up to tetramer containing ammonia were also obtained but these were found to result from naturally charged clusters formed by ion induced clustering in the atmosphere during nucleation. Opposite to earlier studies with cluster mass spectrometers, we had no indication of neutral clusters. The reason is either less efficient charging of clusters in comparison to molecular Sulphuric Acid, or the low concentration of neutral clusters at our measurement site during these particular nucleation events. We show that utilizing high resolution mass spectrometry is crucial in separating the weak sulfuric Acid cluster signal from other compounds.
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Aerosol dynamics simulations on the connection of Sulphuric Acid and new particle formation
Atmospheric Chemistry and Physics, 2008Co-Authors: S.-l. Sihto, Kari E J Lehtinen, Henri Vuollekoski, Johannes Leppä, Ilona Riipinen, V.-m. Kerminen, Hannu Korhonen, Markku KulmalaAbstract:We have performed a series of simulations with an aerosol dynamics box model to study the connection between new particle formation and Sulphuric Acid concentration. For nucleation either activation mechanism with a linear dependence on the Sulphuric Acid concentration, kinetic mechanism with a squared dependence on the Sulphuric Acid concentration or ternary H 2 O-H 2 SO 4 -NH 3 nucleation was assumed. The aim was to study the factors that affect the Sulphuric Acid dependence during the early stages of particle growth, and specifically to find conditions which would yield the linear dependence between the particle number concentration at 3–6 nm and Sulphuric Acid, as observed in field experiments. The simulations showed that the correlation with Sulphuric Acid may change during the growth from nucleation size to 3–6 nm size range, the main reason being the size dependent growth rate between 1 and 3 nm. In addition, the assumed size for the nucleated clusters had a crucial impact on the Sulphuric Acid dependence at 3 nm. A linear dependence between the particle number concentration at 3 nm and Sulphuric Acid was achieved, when activation nucleation mechanism was used with a low saturation vapour pressure for the condensable organic vapour, or with nucleation taking place at ~2 nm instead of ~1 nm. Simulations with activation, kinetic and ternary nucleation showed that ternary nucleation reproduces too steep dependence on Sulphuric Acid as compared to the linear or square dependence observed in field measurements.
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Sulphuric Acid closure and contribution to nucleation mode particle growth
Atmospheric Chemistry and Physics, 2004Co-Authors: Markku Kulmala, T M Ruuskanen, Mari Pihlatie, Anni Reissell, Pasi Aalto, P Keronen, Dal M Maso, Heidi Hellen, Hannele Hakola, R JanssonAbstract:Sulphuric Acid concentrations were measured and calculated based on pseudo steady state model with corresponding measurements of CO, NO x , O 3 , SO 2 , methane and non-methane hydrocarbon (NMHC) concentrations as well as solar spectral irradiance and particle number concentrations with size distributions. The measurements were performed as a part of the EU project QUEST (Quantification of Aerosol Nucleation in the European Boundary layer) during an intensive field campaign, which was conducted in Hyytiala, Finland in March–April 2003. In this paper, the closure between measured and calculated H 2 SO 4 concentrations is investigated. Besides that, also the contribution of Sulphuric Acid to nucleation mode particle growth rates is studied. Hydroxyl and hydroperoxy radical concentrations were determined using a pseudo steady state box model including photo stationary states. The maximum midday OH concentrations ranged between 4.1×10 5 to 1.8×10 6 molecules cm -3 and the corresponding values for HO 2 were 1.0×10 7 to 1.5×10 8 molecules cm -3 . The dominant source term for hydroxyl radicals is the reaction of NO with HO 2 (56%) and the reaction of CO with OH covers around 41% of the sinks. The Sulphuric Acid source term is the reaction SO 2 with OH and the sink term is condensation of Sulphuric Acid. The closure between measured and calculated Sulphuric Acid concentrations is achieved with a high agreement to the measured values. In sensitivity studies, we used different values for the non-methane hydrocarbons, the peroxy radicals and nitrogen dioxide. The best fits between calculated and measured values were found by decreasing the NO 2 concentration when it exceeded values of 1.5 ppb and doubling the non-methane hydrocarbon concentrations. The ratio, standard deviation and correlation coefficient between measured and calculated Sulphuric Acid concentrations are 0.99, 0.412 and 0.645, respectively. The maximum midday Sulphuric Acid concentrations varied between 3×10 5 to 1.9×10 7 molecules cm -3 for the measurements and 3×10 5 to 1.4×10 7 molecules cm -3 for the calculations, respectively. An average participation of Sulphuric Acid to the nucleation mode particle growth rates is 8.8%. Classifying the days into two groups – ''polluted'' days with air masses originated over Central Europe or UK, and ''cleaner'' days with air masses originated over the Northern Atlantic or the Polar regions – reflects an equal Sulphuric Acid contribution to the aerosol growth in both air mass classes.
G Ho - One of the best experts on this subject based on the ideXlab platform.
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Biofilter for generation of concentrated Sulphuric Acid from H2S
Environmental Science and Pollution Research, 2016Co-Authors: K. A. Rabbani, Ahmet Kayaalp, Ralf Cord-ruwisch, W Charles, G HoAbstract:Biofilters are used for the conversion of odorous hydrogen sulphide to odourless sulphate in wastewater treatment plants under the right conditions of moisture and pH. One of the consequences of maintaining the suitable pH and moisture content is the production of large volumes of weakly Acidic leachate. This paper presents a biofilter with a maximum H2S elimination capacity of 16.3 g m(-3) h(-1) and removal efficiency greater than 95 % which produces small volumes (1 mL of solution L(-1) of reactor day(-1)) of Sulphuric Acid with a concentration greater than 5.5 M after 150 days of continuous operation. The concentrated Sulphuric Acid was produced by intermittently trickling a minimum amount of nutrient solution down the upflow biofilter which created a moisture and pH gradient within the biofilter resulting in an environment at the top for the bacterial conversion of H2S, while Sulphuric Acid was accumulated at the base. Genetic diversity profiling of samples taken from different sections of the biofilter confirms that the upper sections of the biofilter had the best environment for the bacteria to convert H2S to sulphate. The formation of concentrated Sulphuric Acid presents an opportunity for the recovery of sulphur from the waste stream as a usable product.
Kari E J Lehtinen - One of the best experts on this subject based on the ideXlab platform.
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a statistical proxy for Sulphuric Acid concentration
Atmospheric Chemistry and Physics, 2011Co-Authors: Santtu Mikkonen, Sami Romakkaniemi, James N Smith, H Korhonen, Christian Plassduelmer, Tuukka Petaja, Peter H. Mcmurry, Kari E J LehtinenAbstract:Abstract. Gaseous Sulphuric Acid is a key precursor for new particle formation in the atmosphere. Previous experimental studies have confirmed a strong correlation between the number concentrations of freshly formed particles and the ambient concentrations of Sulphuric Acid. This study evaluates a body of experimental gas phase Sulphuric Acid concentrations, as measured by Chemical Ionization Mass Spectrometry (CIMS) during six intensive measurement campaigns and one long-term observational period. The campaign datasets were measured in Hyytiala, Finland, in 2003 and 2007, in San Pietro Capofiume, Italy, in 2009, in Melpitz, Germany, in 2008, in Atlanta, Georgia, USA, in 2002, and in Niwot Ridge, Colorado, USA, in 2007. The long term data were obtained in Hohenpeissenberg, Germany, during 1998 to 2000. The measured time series were used to construct proximity measures ("proxies") for Sulphuric Acid concentration by using statistical analysis methods. The objective of this study is to find a proxy for sulfuric Acid that is valid in as many different atmospheric environments as possible. Our most accurate and universal formulation of the Sulphuric Acid concentration proxy uses global solar radiation, SO 2 concentration, condensation sink and relative humidity as predictor variables, yielding a correlation measure ( R ) of 0.87 between observed concentration and the proxy predictions. Interestingly, the role of the condensation sink in the proxy was only minor, since similarly accurate proxies could be constructed with global solar radiation and SO 2 concentration alone. This could be attributed to SO 2 being an indicator for anthropogenic pollution, including particulate and gaseous emissions which represent sinks for the OH radical that, in turn, is needed for the formation of Sulphuric Acid.
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Aerosol dynamics simulations on the connection of Sulphuric Acid and new particle formation
Atmospheric Chemistry and Physics, 2008Co-Authors: S.-l. Sihto, Kari E J Lehtinen, Henri Vuollekoski, Johannes Leppä, Ilona Riipinen, V.-m. Kerminen, Hannu Korhonen, Markku KulmalaAbstract:We have performed a series of simulations with an aerosol dynamics box model to study the connection between new particle formation and Sulphuric Acid concentration. For nucleation either activation mechanism with a linear dependence on the Sulphuric Acid concentration, kinetic mechanism with a squared dependence on the Sulphuric Acid concentration or ternary H 2 O-H 2 SO 4 -NH 3 nucleation was assumed. The aim was to study the factors that affect the Sulphuric Acid dependence during the early stages of particle growth, and specifically to find conditions which would yield the linear dependence between the particle number concentration at 3–6 nm and Sulphuric Acid, as observed in field experiments. The simulations showed that the correlation with Sulphuric Acid may change during the growth from nucleation size to 3–6 nm size range, the main reason being the size dependent growth rate between 1 and 3 nm. In addition, the assumed size for the nucleated clusters had a crucial impact on the Sulphuric Acid dependence at 3 nm. A linear dependence between the particle number concentration at 3 nm and Sulphuric Acid was achieved, when activation nucleation mechanism was used with a low saturation vapour pressure for the condensable organic vapour, or with nucleation taking place at ~2 nm instead of ~1 nm. Simulations with activation, kinetic and ternary nucleation showed that ternary nucleation reproduces too steep dependence on Sulphuric Acid as compared to the linear or square dependence observed in field measurements.
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Aerosol dynamics simulations on the connection of Sulphuric Acid and new particle formation
Atmospheric Chemistry and Physics Discussions, 2008Co-Authors: S.-l. Sihto, H Korhonen, Kari E J Lehtinen, Henri Vuollekoski, Johannes Leppä, Ilona Riipinen, V.-m. Kerminen, M. KulmalaAbstract:Abstract. We have performed a series of simulations with an aerosol dynamics box model to study the connection between new particle formation and Sulphuric Acid concentration. For nucleation either activation mechanism with a linear dependence on the Sulphuric Acid concentration or ternary H2O-H2SO4-NH3 nucleation was assumed. We investigated the factors that affect the Sulphuric Acid dependence during the early stages of particle growth, and tried to find conditions which would yield the linear dependence between the particle number concentration at 3–6 nm and Sulphuric Acid, as observed in field experiments. The simulations showed that the correlation with Sulphuric Acid may change during the growth from nucleation size to 3–6 nm size range, the main reason being the size dependent growth rate between 1 and 3 nm. In addition, the assumed size for the nucleated clusters had a crucial impact on the Sulphuric Acid dependence at 3 nm. The simulations yielded a linear dependence between the particle number concentration at 3 nm and Sulphuric Acid, when a low saturation vapour pressure for the condensable organic vapour was assumed, or when nucleation took place at ~2 nm instead of ~1 nm. Comparison of results with activation and ternary nucleation showed that ternary nucleation cannot explain the experimentally observed linear or square dependence on Sulphuric Acid.
James N Smith - One of the best experts on this subject based on the ideXlab platform.
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a statistical proxy for Sulphuric Acid concentration
Atmospheric Chemistry and Physics, 2011Co-Authors: Santtu Mikkonen, Sami Romakkaniemi, James N Smith, H Korhonen, Christian Plassduelmer, Tuukka Petaja, Peter H. Mcmurry, Kari E J LehtinenAbstract:Abstract. Gaseous Sulphuric Acid is a key precursor for new particle formation in the atmosphere. Previous experimental studies have confirmed a strong correlation between the number concentrations of freshly formed particles and the ambient concentrations of Sulphuric Acid. This study evaluates a body of experimental gas phase Sulphuric Acid concentrations, as measured by Chemical Ionization Mass Spectrometry (CIMS) during six intensive measurement campaigns and one long-term observational period. The campaign datasets were measured in Hyytiala, Finland, in 2003 and 2007, in San Pietro Capofiume, Italy, in 2009, in Melpitz, Germany, in 2008, in Atlanta, Georgia, USA, in 2002, and in Niwot Ridge, Colorado, USA, in 2007. The long term data were obtained in Hohenpeissenberg, Germany, during 1998 to 2000. The measured time series were used to construct proximity measures ("proxies") for Sulphuric Acid concentration by using statistical analysis methods. The objective of this study is to find a proxy for sulfuric Acid that is valid in as many different atmospheric environments as possible. Our most accurate and universal formulation of the Sulphuric Acid concentration proxy uses global solar radiation, SO 2 concentration, condensation sink and relative humidity as predictor variables, yielding a correlation measure ( R ) of 0.87 between observed concentration and the proxy predictions. Interestingly, the role of the condensation sink in the proxy was only minor, since similarly accurate proxies could be constructed with global solar radiation and SO 2 concentration alone. This could be attributed to SO 2 being an indicator for anthropogenic pollution, including particulate and gaseous emissions which represent sinks for the OH radical that, in turn, is needed for the formation of Sulphuric Acid.
K. A. Rabbani - One of the best experts on this subject based on the ideXlab platform.
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Biofilter for generation of concentrated Sulphuric Acid from H2S
Environmental Science and Pollution Research, 2016Co-Authors: K. A. Rabbani, Ahmet Kayaalp, Ralf Cord-ruwisch, W Charles, G HoAbstract:Biofilters are used for the conversion of odorous hydrogen sulphide to odourless sulphate in wastewater treatment plants under the right conditions of moisture and pH. One of the consequences of maintaining the suitable pH and moisture content is the production of large volumes of weakly Acidic leachate. This paper presents a biofilter with a maximum H2S elimination capacity of 16.3 g m(-3) h(-1) and removal efficiency greater than 95 % which produces small volumes (1 mL of solution L(-1) of reactor day(-1)) of Sulphuric Acid with a concentration greater than 5.5 M after 150 days of continuous operation. The concentrated Sulphuric Acid was produced by intermittently trickling a minimum amount of nutrient solution down the upflow biofilter which created a moisture and pH gradient within the biofilter resulting in an environment at the top for the bacterial conversion of H2S, while Sulphuric Acid was accumulated at the base. Genetic diversity profiling of samples taken from different sections of the biofilter confirms that the upper sections of the biofilter had the best environment for the bacteria to convert H2S to sulphate. The formation of concentrated Sulphuric Acid presents an opportunity for the recovery of sulphur from the waste stream as a usable product.
