scholarly journals Amines in boreal forest air at SMEAR II station in Finland

2018 ◽  
Vol 18 (9) ◽  
pp. 6367-6380 ◽  
Author(s):  
Marja Hemmilä ◽  
Heidi Hellén ◽  
Aki Virkkula ◽  
Ulla Makkonen ◽  
Arnaud P. Praplan ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Gas Phase ◽  
Particle Number ◽  
Detection Limits ◽  
Ambient Air ◽  
Monthly Means ◽  
Ammonium Ions ◽  
Quadrupole Mass ◽  
Concentration Data ◽  
Diurnal Variability

Abstract. We measured amines in boreal forest air in Finland both in gas and particle phases with 1 h time resolution using an online ion chromatograph (instrument for Measuring AeRosols and Gases in Ambient Air – MARGA) connected to an electrospray ionization quadrupole mass spectrometer (MS). The developed MARGA-MS method was able to separate and detect seven different amines: monomethylamine (MMA), dimethylamine (DMA), trimethylamine (TMA), ethylamine (EA), diethylamine (DEA), propylamine (PA), and butylamine (BA). The detection limits of the method for amines were low (0.2–3.1 ng m−3), the accuracy of IC-MS analysis was 11–37 %, and the precision 10–15 %. The proper measurements in the boreal forest covered about 8 weeks between March and December 2015. The amines were found to be an inhomogeneous group of compounds, showing different seasonal and diurnal variability. Total MMA (MMA(tot)) peaked together with the sum of ammonia and ammonium ions already in March. In March, monthly means for MMA were < 2.4 and 6.8 ± 9.1 ng m−3 in gas and aerosol phases, respectively, and for NH3 and NH4+ these were 52 ± 16 and 425 ± 371 ng m−3, respectively. Monthly medians in March for MMA(tot), NH3, and NH4+ were < 2.4, 19 and 90 ng m−3, respectively. DMA(tot) and TMA(tot) had summer maxima indicating biogenic sources. We observed diurnal variation for DMA(tot) but not for TMA(tot). The highest concentrations of these compounds were measured in July. Then, monthly means for DMA were < 3.1 and 8.4 ± 3.1 ng m−3 in gas and aerosol phases, respectively, and for TMA these were 0.4 ± 0.1 and 1.8 ± 0.5 ng m−3. Monthly medians in July for DMA were below the detection limit (DL) and 4.9 ng m−3 in gas and aerosol phases, respectively, and for TMA these were 0.4 and 1.4 ng m−3. When relative humidity of air was > 90 %, gas-phase DMA correlated well with 1.1–2 nm particle number concentration (R2=0.63) suggesting that it participates in atmospheric clustering. EA concentrations were low all the time. Its July means were < 0.36 and 0.4 ± 0.4 ng m−3 in gas and aerosol phases, respectively, but individual concentration data correlated well with monoterpene concentrations in July. Monthly means of PA and BA were below detection limits at all times.

scholarly journals Amines in Boreal Forest Air at SMEAR II Station in Finland

2017 ◽  
Author(s):  
Marja Hemmilä ◽  
Heidi Hellén ◽  
Aki Virkkula ◽  
Ulla Makkonen ◽  
Arnaud P. Praplan ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Electrospray Ionization ◽  
Time Resolution ◽  
Ambient Air ◽  
Ammonium Ion ◽  
Monthly Means ◽  
Particle Phase ◽  
Quadrupole Mass ◽  
Diurnal Variability ◽  
Ion Chromatograph

Abstract. We measured amines in boreal forest air in Finland both in gas and particle phase with 1-hour time resolution using an online ion chromatograph (instrument for Measuring AeRosols and Gases in Ambient Air, MARGA) connected to an electrospray ionization quadrupole mass spectrometer (MS). The measurements covered about 8 weeks between March 2015 and December 2015. With MARGA-MS we were able to separate and detect 7 different amines: monomethylamine (MMA), dimethylamine (DMA), trimethylamine (TMA), ethylamine (EA), diethylamine (DEA), propylamine (PA) and butylamine (BA). The amines were found to be an inhomogeneous group of compounds, showing different seasonal and diurnal variability. Total MMA peaked together with the sum of ammonia and ammonium ion already in March, possibly due to evaporation from melting snow and ground. In March monthly means for MMA were

scholarly journals Using in situ GC-MS for analysis of C<sub>2</sub>–C<sub>7</sub> volatile organic acids in ambient air of a boreal forest site

2017 ◽  
Vol 10 (1) ◽  
pp. 281-289 ◽  
Author(s):  
Heidi Hellén ◽  
Simon Schallhart ◽  
Arnaud P. Praplan ◽  
Tuukka Petäjä ◽  
Hannele Hakola
Keyword(s):  
Organic Acids ◽  
Boreal Forest ◽  
Mass Spectrometer ◽  
Detection Limits ◽  
Ambient Air ◽  
Cold Trap ◽  
Mixing Ratios ◽  
Volatile Organic ◽  
Volatile Organic Acids

Abstract. An in situ method for studying gas-phase C2–C7 monocarboxylic volatile organic acids (VOAs) in ambient air was developed and evaluated. Samples were collected directly into the cold trap of the thermal desorption unit (TD) and analysed in situ using a gas chromatograph (GC) coupled to a mass spectrometer (MS). A polyethylene glycol column was used for separating the acids. The method was validated in the laboratory and tested on the ambient air of a boreal forest in June 2015. Recoveries of VOAs from fluorinated ethylene propylene (FEP) and heated stainless steel inlets ranged from 83 to 123 %. Different VOAs were fully desorbed from the cold trap and well separated in the chromatograms. Detection limits varied between 1 and 130 pptv and total uncertainty of the method at mean ambient mixing ratios was between 16 and 76 %. All straight chain VOAs except heptanoic acid in the ambient air measurements were found with mixing ratios above the detection limits. The highest mixing ratios were found for acetic acid and the highest relative variations for hexanoic acid. In addition, mixing ratios of acetic and propanoic acids measured by the novel GC-MS method were compared with proton-mass-transfer time-of-flight mass spectrometer (PTR-TOFMS) data. Both instruments showed similar variations, but differences in the mixing ratio levels were significant.

scholarly journals Analysis of number size distributions of tropical free tropospheric aerosol particles observed at Pico Espejo (4765 m a.s.l.), Venezuela

2011 ◽  
Vol 11 (7) ◽  
pp. 3319-3332 ◽  
Author(s):  
T. Schmeissner ◽  
R. Krejci ◽  
J. Ström ◽  
W. Birmili ◽  
A. Wiedensohler ◽  
...  
Keyword(s):  
Particle Number ◽  
Dry Season ◽  
Number Concentration ◽  
Aerosol Size Distribution ◽  
Particle Number Concentration ◽  
Size Distributions ◽  
Wet Season ◽  
Concentration Data ◽  
Diurnal Variability ◽  
Tropospheric Aerosol

Abstract. The first long-term measurements of aerosol number and size distributions in South-American tropical free troposphere (FT) were performed from March 2007 until March 2009. The measurements took place at the high altitude Atmospheric Research Station Alexander von Humboldt. The station is located on top of the Sierra Nevada mountain ridge at 4765 m a.s.l. nearby the city of Mérida, Venezuela. Aerosol size distribution and number concentration data was obtained with a custom-built Differential Mobility Particle Sizer (DMPS) system and a Condensational Particle Counter (CPC). The analysis of the annual and diurnal variability of the tropical FT aerosol focused mainly on possible links to the atmospheric general circulation in the tropics. Considerable annual and diurnal cycles of the particle number concentration were observed. Highest total particle number concentrations were measured during the dry season (January–March, 519 ± 613 cm−3), lowest during the wet season (July–September, 318 ± 194 cm−3). The more humid FT (relative humidity (RH) range 50–95 %) contained generally higher aerosol particle number concentrations (573 ± 768 cm−3 during dry season, 320 ± 195 cm−3 during wet season) than the dry FT (RH < 50 %, 454 ± 332 cm−3 during dry season, 275 ± 172 cm−3 during wet season), indicating the importance of convection for aerosol distributions in the tropical FT. The diurnal cycle in the variability of the particle number concentration was mainly driven by local orography.

scholarly journals Aerosol particle properties in the tropical free troposphere observed at Pico Espejo (4765 m a.s.l.), Venezuela

2010 ◽  
Vol 10 (11) ◽  
pp. 29153-29189
Author(s):  
T. Schmeißner ◽  
R. Krejci ◽  
J. Ström ◽  
W. Birmili ◽  
A. Wiedensohler ◽  
...  
Keyword(s):  
Aerosol Particle ◽  
Particle Number ◽  
Dry Season ◽  
Number Concentration ◽  
Aerosol Size Distribution ◽  
Particle Number Concentration ◽  
Free Troposphere ◽  
Wet Season ◽  
Concentration Data ◽  
Diurnal Variability

Abstract. The first long-term measurements of aerosol number and size distributions in South-American tropical free troposphere were performed from March 2007 until Mai 2009. The measurements took place at the high altitude Atmospheric Research Station Alexander von Humboldt. The station is located on top of the Sierra Nevada mountain ridge at 4765 m a.s.l. nearby the city of Mérida, Venezuela. Aerosol size distribution and number concentration data was obtained with a custom-built Differential Mobility Particle Sizer (DMPS system) and a Condensational Particle Counter (CPC). The analysis of the annual and diurnal variability of the tropical free troposphere (FT) aerosol focused mainly on possible links to the atmospheric general circulation in the tropics. Considerable annual and diurnal cycles of the particle number concentration were observed. Highest total particle number concentrations were measured during the dry season (519±613 cm−3), lowest during the wet season (318±194 cm−3). The more humid FT contained generally higher aerosol particle number concentrations (573±768 cm−3 during dry season, 320±195 cm−3 during wet season) than the dry FT (454±332 cm−3 during dry season, 275±172 cm−3 during wet season), indicating the importance of convection for aerosol distributions in the tropical FT. The diurnal cycle in the variability of the particle number concentration was mainly driven by local orography.

scholarly journals Amine and guanidine emissions from a boreal forest floor

2020 ◽  
Author(s):  
Marja Hemmilä ◽  
Ulla Makkonen ◽  
Aki Virkkula ◽  
Georgia Panagiotopoulou ◽  
Juho Aalto ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Forest Floor ◽  
Ambient Air ◽  
The Other ◽  
Emission Rates ◽  
Dynamic Flow ◽  
Quadrupole Mass ◽  
Diurnal Cycles ◽  
Chamber Temperature ◽  
Flow Through

Abstract. We measured amine and guanidine emission rates from a boreal forest floor in Finland with 1-h time resolution, using an online ion chromatograph (instrument for Measuring AeRosols and Gases in Ambient air – MARGA) coupled with an electrospray ionization-quadrupole mass spectrometer (MS). MARGA-MS was connected to a closed dynamic flow-through poly(methyl methacrylate) chamber. Chamber recovery for the emission measurements was tested semi-quantitatively for monomethyl-, dimethyl- and trimethylamine (MMA, DMA and TMA), and the results were 19 %, 29 % and 24 %, respectively. MMA, DMA and TMA showed maximum emission rates in July, but the highest emission rates for guanidine were in April, when snow was melting. The MMA, DMA and TMA emission rates also clearly varied diurnally, especially in July with maxima at afternoon. Diethylamine (DEA) also showed higher emission rates, with clear diurnal cycles in July. Other amine emission rates were mostly below the detection limits. The temperature dependencies of the emissions were studied, and we noted a correlation between the emission rates and chamber temperature (Tchamber). Especially in July emission rates of DMA followed Tchamber measured two hours earlier and guanidine showed a similar pattern. On the other hand, the TMA emission rates correlated with Tchamber measured at the same time. This could be due to lower vaporizing temperature of TMA. Emission rates of DMA and TMA showed some air temperature (Tair) dependency, but for MMA dependency was not as clear.

scholarly journals Filling the gaps of in situ hourly PM<sub>2.5</sub> concentration data with the aid of empirical orthogonal function analysis constrained by diurnal cycles

2020 ◽  
Vol 13 (3) ◽  
pp. 1213-1226 ◽  
Author(s):  
Kaixu Bai ◽  
Ke Li ◽  
Jianping Guo ◽  
Yuanjian Yang ◽  
Ni-Bin Chang
Keyword(s):  
Air Quality ◽  
Empirical Orthogonal Function ◽  
Diurnal Cycle ◽  
Ambient Air ◽  
Concentration Data ◽  
Diurnal Variability ◽  
Orthogonal Function ◽  
Good Prediction Accuracy ◽  
Data Gaps ◽  
Pm2.5 Concentration

Abstract. Data gaps in surface air quality measurements significantly impair the data quality and the exploration of these valuable data sources. In this study, a novel yet practical method called diurnal-cycle-constrained empirical orthogonal function (DCCEOF) was developed to fill in data gaps present in data records with evident temporal variability. The hourly PM2.5 concentration data retrieved from the national ambient air quality monitoring network in China were used as a demonstration. The DCCEOF method aims to reconstruct the diurnal cycle of PM2.5 concentration from its discrete neighborhood field in space and time firstly and then predict the missing values by calibrating the reconstructed diurnal cycle to the level of valid PM2.5 concentrations observed at adjacent times. The statistical results indicate a high frequency of data gaps in our retrieved hourly PM2.5 concentration record, with PM2.5 concentration measured on about 40 % of the days suffering from data gaps. Further sensitivity analysis results reveal that data gaps in the hourly PM2.5 concentration record may introduce significant bias to its daily averages, especially during clean episodes at which PM2.5 daily averages are observed to be subject to larger uncertainties compared to the polluted days (even in the presence of the same amount of missingness). The cross-validation results indicate that our suggested DCCEOF method has a good prediction accuracy, particularly in predicting daily peaks and/or minima that cannot be restored by conventional interpolation approaches, thus confirming the effectiveness of the consideration of the local diurnal variation pattern in gap filling. By applying the DCCEOF method to the hourly PM2.5 concentration record measured in China from 2014 to 2019, the data completeness ratio was substantially improved while the frequency of days with gapped PM2.5 records reduced from 42.6 % to 5.7 %. In general, our DCCEOF method provides a practical yet effective approach to handle data gaps in time series of geophysical parameters with significant diurnal variability, and this method is also transferable to other data sets with similar barriers because of its self-consistent capability.

scholarly journals Using in situ GC-MS for analysis of C<sub>2</sub>-C<sub>7</sub> volatile organic acids in ambient air of a boreal forest site

2016 ◽  
Author(s):  
Heidi Hellén ◽  
Simon Schallhart ◽  
Arnaud P. Praplan ◽  
Tuukka Petäjä ◽  
Hannele Hakola
Keyword(s):  
Organic Acids ◽  
Boreal Forest ◽  
Mass Spectrometer ◽  
Detection Limits ◽  
Ambient Air ◽  
Cold Trap ◽  
Mixing Ratios ◽  
Volatile Organic ◽  
Volatile Organic Acids

Abstract. Abstract. An in situ method for studying C2-C7 monocarboxylic volatile organic acids (VOAs) in ambient air was developed and evaluated. Samples were collected directly into the cold trap of the thermal desorption unit (TD) and analysed in situ using a gas chromatograph (GC) coupled to a mass spectrometer (MS). A polyethylene glycol column was used for separating the acids. The method was validated in the laboratory and tested on the ambient air of a boreal forest in June 2015. Recoveries of VOAs from fluorinated ethylene propylene (FEP) and heated stainless steel inlets were acceptable. Different VOAs were fully desorbed from the cold trap and well separated in the chromatograms. Detection limits varied between 1 and 130 pptv and total uncertainty of the method at mean ambient mixing ratios ranged between 16–76 %. All straight chain VOAs except heptanoic acid in the ambient air measurement were found with mixing ratios above the detection limits. The highest mixing ratios were found for acetic acid and the highest relative variations for hexanoic acid. In addition, mixing ratios of acetic and propanoic acids measured by the novel GC-MS method were compared with proton-mass-transfer time-of-flight mass spectrometer (PTR-TOFMS) data. Both instruments showed similar variations, but differences in the mixing ratio levels were significant.

Annual and interannual variation in boreal forest aerosol particle number and volume concentration and their connection to particle formation

Tellus B ◽  
2008 ◽  
Vol 60 (4) ◽  
Author(s):  
Miikka Dal Maso ◽  
Antti Hyvärinen ◽  
Mika Komppula ◽  
Peter Tunved ◽  
Veli-Matti Kerminen ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Aerosol Particle ◽  
Interannual Variation ◽  
Particle Number ◽  
Volume Concentration ◽  
Particle Formation
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