scholarly journals Uptake of nitric acid, ammonia, and organics in orographic clouds: mass spectrometric analyses of droplet residual and interstitial aerosol particles

2017 ◽  
Vol 17 (2) ◽  
pp. 1571-1593 ◽  
Author(s):  
Johannes Schneider ◽  
Stephan Mertes ◽  
Dominik van Pinxteren ◽  
Hartmut Herrmann ◽  
Stephan Borrmann
Keyword(s):  
Nitric Acid ◽  
Black Carbon ◽  
Aqueous Phase ◽  
Aerosol Particles ◽  
Organic Nitrates ◽  
Temperature Dependent ◽  
Cloud Droplets ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Mass Fractions

Abstract. Concurrent in situ analyses of interstitial aerosol and cloud droplet residues have been conducted at the Schmücke mountain site during the Hill Cap Cloud Thuringia campaign in central Germany in September and October 2010. Cloud droplets were sampled from warm clouds (temperatures between −3 and +16 °C) by a counterflow virtual impactor and the submicron-sized residues were analyzed by a compact time-of-flight aerosol mass spectrometer (C-ToF-AMS), while the interstitial aerosol composition was measured by an high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). During cloud-free periods, the submicron out-of-cloud aerosol was analyzed using both instruments, allowing for intercomparison between the two instruments. Further instrumentation included black carbon measurements and optical particle counters for the aerosol particles as well as optical sizing instrumentation for the cloud droplets. The results show that, under cloud conditions, on average 85 % of the submicron aerosol mass partitioned into the cloud liquid phase. Scavenging efficiencies of nitrate, ammonium, sulfate, and organics ranged between 60 and 100 %, with nitrate having, in general, the highest values. For black carbon, the scavenging efficiency was markedly lower (about 24 %). The nitrate and ammonium mass fractions were found to be markedly enhanced in cloud residues, indicating uptake of gaseous nitric acid and ammonia into the aqueous phase. This effect was found to be temperature dependent: at lower temperatures, the nitrate and ammonium mass fractions in the residues were higher. Also, the oxidation state of the organic matter in cloud residues was found to be temperature dependent: the O : C ratio was lower at higher temperatures. A possible explanation for this observation is a more effective uptake and/or higher concentrations of low-oxidized water-soluble volatile organic compounds, possibly of biogenic origin, at higher temperatures. Organic nitrates were observed in cloud residuals as well as in the out-of-cloud aerosol, but no indication of a preferred partitioning of organic nitrates into the aqueous phase or into the gas phase was detected. Assuming the uptake of nitric acid and ammonia in cloud droplets will be reversible, it will lead to a redistribution of nitrate and ammonium among the aerosol particles, leading to more uniform, internally mixed particles after several cloud passages.

scholarly journals Uptake of nitric acid, ammonia, and organics in orographic clouds: Mass spectrometric analyses of droplet residual and interstitial aerosol particles

2016 ◽  
Author(s):  
Johannes Schneider ◽  
Stephan Mertes ◽  
Dominik van Pinxteren ◽  
Hartmut Herrmann ◽  
Stephan Borrmann
Keyword(s):  
Nitric Acid ◽  
Black Carbon ◽  
Aqueous Phase ◽  
Aerosol Particles ◽  
Water Soluble ◽  
Organic Nitrates ◽  
Temperature Dependent ◽  
Cloud Droplets ◽  
Mass Fractions ◽  
Orographic Clouds

Abstract. Concurrent in-situ analyses of interstitial aerosol and cloud droplet residues have been conducted at the Schmücke mountain site during the Hill Cap Cloud Thuringia campaign in central Germany in September and October 2010. Cloud droplets were sampled from warm clouds (temperatures between −3 and +16 °C) by a counterflow virtual impactor and the submicron-sized residues were analyzed by a C-ToF-AMS, while the interstitial aerosol composition was measured by an HR-ToF-AMS. During cloud-free periods the submicron out-of-cloud aerosol was analyzed using both instruments, allowing for intercomparison between the two instruments. Further instrumentation included black carbon measurements and optical particle counters for the aerosol particles as well as optical sizing instrumentation for the cloud droplets. The results show that under cloud conditions on average 85 % of the submicron aerosol mass partitioned into the cloud liquid phase. Scavenging efficiencies of nitrate, ammonium, sulfate, and organics ranged between 60 and 100 %, with nitrate having in general the highest values. For black carbon, the scavenging efficiency was markedly lower (about 24 %). The nitrate and ammonium mass fractions were found to be markedly enhanced in cloud residues, indicating uptake of gaseous nitric acid and ammonia into the aqueous phase. This effect was found to be temperature dependent: At lower temperatures the nitrate and ammonium mass fractions in the residues were higher. Also, the oxidation state of the organic matter in cloud residues was found to be temperature dependent: The O:C ratio was lower at higher temperatures. A possible explanation for this observation is a more effective uptake and/or higher concentrations of low-oxidized water soluble volatile organic compounds, possibly of biogenic origin, at higher temperatures. Organic nitrates were observed in cloud residuals as well as in the out-of-cloud aerosol, but no indication of a preferred partitioning of organic nitrates into the aqueous phase or into the gas phase was detected. Assuming the uptake of nitric acid and ammonia in cloud droplets to be reversible, it will lead to a redistribution of nitrate and ammonium among the aerosol particles, leading to more uniform, internally mixed particles after several cloud passages.

scholarly journals Summertime aerosol volatility measurements in Beijing, China

2019 ◽  
Author(s):  
Weiqi Xu ◽  
Conghui Xie ◽  
Eleni Karnezi ◽  
Qi Zhang ◽  
Junfeng Wang ◽  
...  
Keyword(s):  
Aerosol Particles ◽  
High Mass ◽  
Transfer Model ◽  
Organic Nitrates ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Metallic Salts ◽  
Volatile Organic ◽  
Effective Saturation ◽  
Beijing China

Abstract. Volatility plays a key role in affecting mass concentrations and lifetime of aerosol particles in the atmosphere, yet our knowledge of aerosol volatility in relatively polluted environment, e.g., north China remains poor. Here aerosol volatility in Beijing in summer 2017 and 2018 was measured using a thermodenuder (TD) coupled with an Aerodyne high-resolution aerosol mass spectrometer (AMS) and a soot particle AMS. Our results showed overall similar thermograms for most non-refractory aerosol species compared with those reported in previous studies. However, high mass fraction remaining and NO+/NO2+ ratio for chloride and nitrate, respectively above 200 °C indicated the presence of considerable metallic salts and organic nitrates in Beijing. The volatility distributions of organic aerosol (OA) and four OA factors that were resolved from positive matrix factorization were estimated using a mass transfer model. The ambient OA comprised mainly semi-volatile organic compounds (SVOC, 63 %) with an average effective saturation concentration (C*) of 0.55 µg m−3, suggesting overall more volatile properties than OA in megacities of Europe and US. Further analysis showed that the freshly oxidized secondary OA (LO-OOA) was the most volatile OA factor (SVOC = 70 %) followed by hydrocarbon-like OA (HOA). In contrast, the volatility of more oxidized SOA (MO-OOA) was comparable to that of cooking OA with SVOC on average accounting for 60.2 %. We also compared the volatility of ambient and black carbon–containing OA. Our results showed that the BC-containing primary OA (POA) was much more volatile than ambient POA (C*= 0.69 µg m−3 vs. 0.37 µg m−3), while the BC-containing SOA was much less volatile, highlighting the very different composition and properties between BC-containing and ambient aerosol particles.

scholarly journals Summertime aerosol volatility measurements in Beijing, China

2019 ◽  
Vol 19 (15) ◽  
pp. 10205-10216 ◽  
Author(s):  
Weiqi Xu ◽  
Conghui Xie ◽  
Eleni Karnezi ◽  
Qi Zhang ◽  
Junfeng Wang ◽  
...  
Keyword(s):  
Aerosol Particles ◽  
High Mass ◽  
Transfer Model ◽  
Organic Nitrates ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Metallic Salts ◽  
The Us ◽  
Effective Saturation ◽  
Beijing China

Abstract. Volatility plays a key role in affecting mass concentrations and the lifetime of aerosol particles in the atmosphere, yet our knowledge of aerosol volatility in relatively polluted environment, e.g., north China, remains poor. Here aerosol volatility in Beijing in summer 2017 and 2018 was measured using a thermodenuder (TD) coupled with an Aerodyne high-resolution aerosol mass spectrometer (AMS) and a soot particle AMS. Our results showed overall similar thermograms for most non-refractory aerosol species compared with those reported in previous studies. However, high mass fraction remaining and NO+/NO2+ ratio for chloride and nitrate, each above 200 ∘C, indicated the presence of considerable metallic salts and organic nitrates in Beijing. The volatility distributions of organic aerosol (OA) and four OA factors that were resolved from positive matrix factorization were estimated using a mass transfer model. The ambient OA comprised mainly semi-volatile organic compounds (SVOCs; 63 %) with an average effective saturation concentration (C*) of 0.55 µg m−3, suggesting overall more volatile properties than OA in megacities of Europe and the US. Further analysis showed that the freshly oxidized secondary OA was the most volatile OA factor (SVOC = 70 %) followed by hydrocarbon-like OA (HOA). In contrast, the volatility of more oxidized oxygenated OA (MO-OOA) was comparable to that of cooking OA with SVOC on average accounting for 60.2 %. We also compared the volatility of ambient and black-carbon-containing OA. Our results showed that the BC-containing primary OA (POA) was much more volatile than ambient POA (C*=0.69 µg m−3 vs. 0.37 µg m−3), while the BC-containing SOA was much less volatile, highlighting the very different composition and properties between BC-containing and ambient aerosol particles.

scholarly journals Long-term volatility measurements of submicron atmospheric aerosol in Hyytiälä, Finland

2012 ◽  
Vol 12 (5) ◽  
pp. 11201-11244 ◽  
Author(s):  
S. A. K. Häkkinen ◽  
M. Äijälä ◽  
K. Lehtipalo ◽  
H. Junninen ◽  
J. Backman ◽  
...  
Keyword(s):  
Black Carbon ◽  
Mass Fraction ◽  
Aerosol Particles ◽  
Volatile Fraction ◽  
Organic Nitrate ◽  
Forest Site ◽  
Volatile Material ◽  
Seasonal Behavior ◽  
Aerosol Mass ◽  
Mass Fractions

Abstract. The volatility of atmospheric 20–500 nm aerosol particles was investigated at a boreal forest site in Hyytiälä, Finland. Measurements were performed continuously between January 2008 and May 2010. The ambient aerosol sample was heated step-wise to six temperatures ranging from 80 °C to 280 °C and the total mass concentration of aerosol particles was determined from the measured particle number size distributions before and after heating assuming particle density of 1.6 g cm−3. On average 19% of the total aerosol mass stayed in the condensed phase even after heating to 280 °C. The observed non-volatile residual at 280 °C had a seasonal pattern; during winter the aerosol mass fraction remaining after heating was the highest and during summer the lowest. Black carbon concentrations correlated positively with the non-volatile fraction of the aerosol, but could not explain the presence of the non-volatile material completely: most of the time a notable fraction of the non-volatile residual was something else than black carbon. Using additional information on ambient meteorological conditions and trajectories, and results from an Aerodyne aerosol mass spectrometer (AMS), the chemical composition of the non-volatile residual and its seasonal behavior was further examined. During winter and spring months the non-volatile mass fraction had a marked positive linear correlation with pollutant trace gases, such as CO, SO2 and NOx. This suggests an anthropogenic influence on the non-volatile fraction of the aerosol in winter and spring. The anthropogenic effect on the formation of the low-volatility material was furthermore supported by observed correlation between the non-volatile residual and the mass fractions of poly-aromatic hydrocarbons (PAHs) sampled simultaneously at the site. During the fall the aerosol particles had relatively more non-volatile material in them when the aerosol mass fractions of organic nitrate and organics in the AMS data were high, and when the measurement site was influenced by clean air masses passing over the forest. Thus, the existence of very low volatile organic nitrates in the aerosol phase can be speculated.

scholarly journals Collection efficiency of the soot-particle aerosol mass spectrometer (SP-AMS) for internally mixed particulate black carbon

2014 ◽  
Vol 7 (12) ◽  
pp. 4507-4516 ◽  
Author(s):  
M. D. Willis ◽  
A. K. Y. Lee ◽  
T. B. Onasch ◽  
E. C. Fortner ◽  
L. R. Williams ◽  
...  
Keyword(s):  
Laser Beam ◽  
Black Carbon ◽  
Mass Spectrometer ◽  
Soot Particle ◽  
Collection Efficiency ◽  
Particle Beam ◽  
Aerosol Mass Spectrometer ◽  
Coated Particles ◽  
Aerosol Mass ◽  
Wide Range

Abstract. The soot-particle aerosol mass spectrometer (SP-AMS) uses an intra-cavity infrared laser to vaporize refractory black carbon (rBC) containing particles, making the particle beam–laser beam overlap critical in determining the collection efficiency (CE) for rBC and associated non-refractory particulate matter (NR-PM). This work evaluates the ability of the SP-AMS to quantify rBC and NR-PM mass in internally mixed particles with different thicknesses of organic coating. Using apparent relative ionization efficiencies for uncoated and thickly coated rBC particles, we report measurements of SP-AMS sensitivity to NR-PM and rBC, for Regal Black, the recommended particulate calibration material. Beam width probe (BWP) measurements are used to illustrate an increase in sensitivity for highly coated particles due to narrowing of the particle beam, which enhances the CE of the SP-AMS by increasing the laser beam–particle beam overlap. Assuming complete overlap for thick coatings, we estimate CE for bare Regal Black particles of 0.6 ± 0.1, which suggests that previously measured SP-AMS sensitivities to Regal Black were underestimated by up to a factor of 2. The efficacy of the BWP measurements is highlighted by studies at a busy road in downtown Toronto and at a non-roadside location, which show particle beam widths similar to, but greater than that of bare Regal Black and coated Regal Black, respectively. Further BWP measurements at field locations will help to constrain the range of CE for fresh and aged rBC-containing particles. The ability of the SP-AMS to quantitatively assess the composition of internally mixed particles is validated through measurements of laboratory-generated organic coated particles, which demonstrate that the SP-AMS can quantify rBC and NR-PM over a wide range of particle compositions and rBC core sizes.

scholarly journals A Black Carbon‐Tracer Method for Estimating Cooking Organic Aerosol From Aerosol Mass Spectrometer Measurements

2019 ◽  
Vol 46 (14) ◽  
pp. 8474-8483 ◽  
Author(s):  
Yao He ◽  
Yele Sun ◽  
Qingqing Wang ◽  
Wei Zhou ◽  
Weiqi Xu ◽  
...  
Keyword(s):  
Black Carbon ◽  
Mass Spectrometer ◽  
Organic Aerosol ◽  
Tracer Method ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass

scholarly journals Highly time-resolved chemical characterization of atmospheric submicron particles during 2008 Beijing Olympic Games using an Aerodyne High-Resolution Aerosol Mass Spectrometer

2010 ◽  
Vol 10 (18) ◽  
pp. 8933-8945 ◽  
Author(s):  
X.-F. Huang ◽  
L.-Y. He ◽  
M. Hu ◽  
M. R. Canagaratna ◽  
Y. Sun ◽  
...  
Keyword(s):  
High Resolution ◽  
Mass Spectrometer ◽  
Olympic Games ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Organic Mass ◽  
Aerosol Mass Spectrometer ◽  
Beijing Olympic Games ◽  
Aerosol Mass ◽  
2008 Beijing Olympic Games

Abstract. As part of Campaigns of Air Quality Research in Beijing and Surrounding Region-2008 (CAREBeijing-2008), an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed in urban Beijing to characterize submicron aerosol particles during the time of 2008 Beijing Olympic Games and Paralympic Games (24 July to 20 September 2008). The campaign mean PM1 mass concentration was 63.1 ± 39.8 μg m−3; the mean composition consisted of organics (37.9%), sulfate (26.7%), ammonium (15.9%), nitrate (15.8%), black carbon (3.1%), and chloride (0.87%). The average size distributions of the species (except BC) were all dominated by an accumulation mode peaking at about 600 nm in vacuum aerodynamic diameter, and organics was characterized by an additional smaller mode extending below 100 nm. Positive Matrix Factorization (PMF) analysis of the high resolution organic mass spectral dataset differentiated the organic aerosol into four components, i.e., hydrocarbon-like (HOA), cooking-related (COA), and two oxygenated organic aerosols (OOA-1 and OOA-2), which on average accounted for 18.1, 24.4, 33.7 and 23.7% of the total organic mass, respectively. The HOA was identified to be closely associated with primary combustion sources, while the COA mass spectrum and diurnal pattern showed similar characteristics to that measured for cooking emissions. The OOA components correspond to aged secondary organic aerosol. Although the two OOA components have similar elemental (O/C, H/C) compositions, they display differences in mass spectra and time series which appear to correlate with the different source regions sampled during the campaign. Back trajectory clustering analysis indicated that the southerly air flows were associated with the highest PM1 pollution during the campaign. Aerosol particles in southern airmasses were especially rich in inorganic and oxidized organic species. Aerosol particles in northern airmasses contained a large fraction of primary HOA and COA species, probably due to stronger influences from local emissions. The lowest concentration levels for all major species were obtained during the Olympic game days (8 to 24 August 2008), possibly due to the effects of both strict emission controls and favorable meteorological conditions.

scholarly journals The single-particle mixing state and cloud scavenging of black carbon: a case study at a high-altitude mountain site in southern China

2017 ◽  
Vol 17 (24) ◽  
pp. 14975-14985 ◽  
Author(s):  
Guohua Zhang ◽  
Qinhao Lin ◽  
Long Peng ◽  
Xinhui Bi ◽  
Duohong Chen ◽  
...  
Keyword(s):  
Black Carbon ◽  
Single Particle ◽  
Southern China ◽  
Cloud Droplet ◽  
Mixing State ◽  
Cloud Droplets ◽  
Aerosol Mass ◽  
Mountain Site ◽  
Cloud Scavenging ◽  
Scavenging Efficiency

Abstract. In the present study, a ground-based counterflow virtual impactor (GCVI) was used to sample cloud droplet residual (cloud RES) particles, while a parallel PM2.5 inlet was used to sample cloud-free or cloud interstitial (cloud INT) particles. The mixing state of black carbon (BC)-containing particles and the mass concentrations of BC in the cloud-free, RES and INT particles were investigated using a single-particle aerosol mass spectrometer (SPAMS) and two aethalometers, respectively, at a mountain site (1690 m a. s. l. ) in southern China. The measured BC-containing particles were extensively internally mixed with sulfate and were scavenged into cloud droplets (with number fractions of 0.05–0.45) to a similar (or slightly lower) extent as all the measured particles (0.07–0.6) over the measured size range of 0.1–1.6 µm. The results indicate the preferential activation of larger particles and/or that the production of secondary compositions shifts the BC-containing particles towards larger sizes. BC-containing particles with an abundance of both sulfate and organics were scavenged less than those with sulfate but limited organics, implying the importance of the mixing state on the incorporation of BC-containing particles into cloud droplets. The mass scavenging efficiency of BC with an average of 33 % was similar for different cloud events independent of the air mass. This is the first time that both the mixing state and cloud scavenging of BC in China have been reported. Our results would improve the knowledge on the concentration, mixing state, and cloud scavenging of BC in the free troposphere.

scholarly journals Factor analysis of combined organic and inorganic aerosol mass spectra from high resolution aerosol mass spectrometer measurements

2012 ◽  
Vol 12 (5) ◽  
pp. 13299-13335
Author(s):  
Y. L. Sun ◽  
Q. Zhang ◽  
J. J. Schwab ◽  
T. Yang ◽  
N. L. Ng ◽  
...  
Keyword(s):  
High Resolution ◽  
Ammonium Nitrate ◽  
Mass Spectrometer ◽  
Mass Spectra ◽  
Organic Nitrates ◽  
Aerosol Mass Spectrometer ◽  
Inorganic Aerosols ◽  
Aerosol Mass ◽  
Inorganic Species ◽  
Mixing Characteristics

Abstract. The high resolution mass spectra of organic and inorganic aerosols from aerosol mass spectrometer (AMS) measurements were first combined into positive matrix factorization (PMF) analysis to investigate the sources and evolution processes of atmospheric aerosols. The new approach is able to study the mixing of organic aerosols (OA) and inorganic species, the acidity of OA factors, and the fragment ion patterns related to photochemical processing. In this study, PMF analysis of the unified AMS spectral matrices resolved 8 factors for the submicron aerosols measured at Queens College in New York City in summer 2009. The hydrocarbon-like OA (HOA) and cooking OA (COA) contain very minor inorganic species, indicating the different sources and mixing characteristics between primary OA and secondary species. The two factors that are primarily ammonium sulfate (SO4-OA) and ammonium nitrate (NO3-OA), respectively, are overall neutralized, of which the OA in SO4-OA shows the highest oxidation state (O/C = 0.69) among OA factors. The semi-volatile oxygenated OA comprises two components, i.e., a less oxidized (LO-OOA) and a more oxidized (MO-OOA). The MO-OOA represents a local photochemical product with the diurnal profile exhibiting a pronounced noon peak, consistent with those of formaldehyde (HCHO) and Ox (= O3+NO2). The much higher NO+/NO2+ fragment ion ratio in MO-OOA than that from ammonium nitrate alone provides evidence for the formation of organic nitrates. The amine-related nitrogen-enriched OA (NOA) contains ~25% of acidic inorganic salts, elucidating the formation of secondary OA from amines in acidic environments. The size distributions derived from 3-dimensional size-resolved mass spectra show distinct diurnal evolving behaviors for different OA factors, but overall a progressing evolution from smaller to larger particle mode as a function of oxidation states. Our results demonstrate that PMF analysis by incorporating inorganic aerosols is of importance for gaining more insights into the sources and processes, mixing characteristics, and acidity of OA.

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