scholarly journals Hygroscopic properties of newly formed ultrafine particles at an urban site surrounded by deciduous forest (Sapporo, northern Japan) during the summer of 2011

2014 ◽  
Vol 14 (14) ◽  
pp. 7519-7531 ◽  
Author(s):  
J. Jung ◽  
K. Kawamura
Keyword(s):  
Growth Factor ◽  
Ultrafine Particles ◽  
Deciduous Forest ◽  
Urban Site ◽  
Hygroscopic Growth ◽  
Organic Vapors ◽  
Nucleation Mode ◽  
Hygroscopic Properties ◽  
Aitken Mode ◽  
Northern Japan

Abstract. To investigate the hygroscopic properties of ultrafine particles during new particle formation events, the hygroscopic growth factors of size-segregated atmospheric particles were measured at an urban site in Sapporo, northern Japan, during the summer of 2011. The hygroscopic growth factor at 85 % relative humidity [g(85%)] of freshly formed nucleation mode particles was 1.11 to 1.28 (average: 1.16 ± 0.06) at a dry particle diameter (Dp) centered on 20 nm, which is equivalent to 1.17 to 1.35 (1.23 ± 0.06) at a dry Dp centered on 100 nm after considering the Kelvin effect. These values are comparable with those of secondary organic aerosols, suggesting that low-volatility organic vapors are important to the burst of nucleation mode particles. The equivalent g(85%) at a dry Dp of 100 nm for nucleated particles that have grown to Aitken mode sizes (1.24 to 1.34; average: 1.30 ± 0.04) were slightly higher than those of newly formed nucleation mode particles, suggesting that the growth of freshly formed nucleation mode particles to the Aitken mode size can be subjected to condensation of not only low-volatility organic vapors, but also water-soluble inorganic species. Based on this result, and previous measurement of radiocarbon in aerosols, we suggest that the burst of nucleation mode particles and their subsequent growth were highly affected by biogenic organic emissions at this measurement site, which is surrounded by deciduous forest. Gradual increases in mode diameter after the burst of nucleation mode particles were observed under southerly wind conditions, with a dominant contribution of intermediately hygroscopic particles. However, sharp increases in mode diameter were observed when the wind direction shifted to northwesterly or northeasterly, with a sharp increase in the highly hygroscopic particle fraction of the Aitken mode particles, indicating that the hygroscopic growth factor of newly formed particles is perturbed by the local winds that deliver different air masses to the measurement site.

scholarly journals Hygroscopic properties of newly formed ultrafine particles at an urban site surrounded by a deciduous forest in northern Japan during the summer of 2011

2014 ◽  
Vol 14 (6) ◽  
pp. 8257-8285
Author(s):  
J. Jung ◽  
K. Kawamura
Keyword(s):  
Growth Factors ◽  
Ultrafine Particles ◽  
Deciduous Forest ◽  
Urban Site ◽  
Hygroscopic Growth ◽  
Air Masses ◽  
Hygroscopic Property ◽  
Nucleation Mode ◽  
Hygroscopic Properties ◽  
Northern Japan

Abstract. To investigate the hygroscopic property of ultrafine particles during the new particle formation event, hygroscopic growth factors (g(RH)) of size-segregated atmospheric particles were measured at an urban site in Sapporo, northern Japan, during the summer of 2011. Hygroscopic growth factors at 85% RH (g(85%)) of freshly formed nucleation mode particles were measured at a dry particle diameter (Dp) centered at 20 nm to be 1.11 to 1.28 (average 1.16 ± 0.06), which are equivalent to 1.17 to 1.35 (1.23 ± 0.06) for a dry Dp centered at 100 nm after considering the Kelvin effect. These values are comparable with those of secondary organic aerosols, suggesting that low-volatility organic vapors are important to the burst of nucleation mode particles at the measurement site surrounded by a deciduous forest. Gradual increases in mode diameter after the burst of nucleation mode particles were obtained under southerly wind condition with a dominant contribution of intermediately-hygroscopic particles. However, sharp increases in mode diameter were obtained when wind direction shifted to northwesterly or northeasterly with a sharp increase in highly-hygroscopic particle faction in the Aitken mode particles, indicating that local wind direction is an important factor controlling the growth of newly formed particles and their hygroscopic properties. Higher g(85%) values (1.27 ± 0.05) were obtained at a dry Dp of 120 nm when the air masses originated from the Asian Continent, whereas lower g(85%) values (1.19 ± 0.06) were obtained when clean marine air masses arrived at the urban site. These results indicate that the hygroscopic property of large Aitken and small accumulation mode particles (80–165 nm) is highly influenced by the long-range atmospheric transport of particles and their precursors.

scholarly journals Different characteristics of new particle formation between urban and deciduous forest sites in Northern Japan during the summers of 2010–2011

2012 ◽  
Vol 12 (6) ◽  
pp. 14043-14087
Author(s):  
J. Jung ◽  
Y. Miyazaki ◽  
K. Kawamura
Keyword(s):  
Wind Direction ◽  
Deciduous Forest ◽  
Particle Formation ◽  
Urban Site ◽  
Forest Site ◽  
New Particle Formation ◽  
Air Masses ◽  
Nucleation Mode ◽  
Prevailing Wind Direction ◽  
Northern Japan

Abstract. To investigate new particle formation (NPF) events in urban and forest environments, number size distributions of ultrafine particles were measured at an urban site and a deciduous forest site in Sapporo, Northern Japan, during the summers of 2011 and 2010, respectively. The burst of nucleation mode particles at the urban site typically started in the morning (7:00–11:30 local time, LT) with simultaneous increases in SO2 and O3 concentrations and the UV index under clear (sunny) weather conditions. The growth rates of nucleated particles at the urban site ranged from 5.0 to 7.8 nm h−1 with an average of 6.3 ± 1.1 nm h−1. NPF events at the urban site were separated into events with or without subsequent particle growth after the burst of nucleation mode particles. This division was related to prevailing wind direction as the subsequent growth of freshly nucleated particles typically occurred when wind direction shifted to northwesterly (from residential and public park areas), whereas it did not occur under southeasterly winds (from the downtown area). During the periods with NPF events, elevated concentrations of non-methane hydrocarbons (NMHC) were obtained under conditions of northwesterly winds when compared to southeasterly winds, whereas no difference in SO2 levels was recorded. These results suggest that variations in NMHC concentration may play an important role in the growth of freshly nucleated particles at the urban site. The burst of nucleation mode particles at the forest site typically started around noon (10:30–14:30 LT), which was 3–4 h later than that at the urban site. Interestingly, at the forest site the burst of nucleation mode particles usually started when air masses originating from urban Sapporo arrived at the forest site. The present study indicates that the inflow of these urban air masses acted as a trigger for the initiation of the burst of nucleation mode particles in the deciduous forest.

scholarly journals Different characteristics of new particle formation between urban and deciduous forest sites in Northern Japan during the summers of 2010–2011

2013 ◽  
Vol 13 (1) ◽  
pp. 51-68 ◽  
Author(s):  
J. Jung ◽  
Y. Miyazaki ◽  
K. Kawamura
Keyword(s):  
Wind Direction ◽  
Deciduous Forest ◽  
Particle Formation ◽  
Urban Site ◽  
Forest Site ◽  
New Particle Formation ◽  
Air Masses ◽  
Nucleation Mode ◽  
Prevailing Wind Direction ◽  
Northern Japan

Abstract. To investigate new particle formation (NPF) events in urban and forest environments, number size distributions of ultrafine particles were measured at an urban site and a deciduous forest site in Sapporo, Northern Japan, during the summers of 2011 and 2010, respectively. The burst of nucleation mode particles at the urban site typically started in the morning (07:00–11:30 local time, LT) with simultaneous increases in SO2 and O3 concentrations and the UV index under clear (sunny) weather conditions. The growth rates of nucleated particles at the urban site ranged from 5.0 to 7.8 nm h−1 with an average of 6.3 ± 1.1 nm h−1. NPF events at the urban site were separated into events with or without subsequent particle growth after the burst of nucleation mode particles. This division was found to relate to prevailing wind direction because the subsequent growth of freshly nucleated particles typically occurred when wind direction shifted to northwesterly (from residential and public park areas), whereas it did not occur under southeasterly winds (from the downtown area). During the periods with NPF events, elevated concentrations of non-methane hydrocarbons (NMHC) were obtained under conditions of northwesterly winds when compared to southeasterly winds, whereas no difference in SO2 levels was recorded. These results suggest that variations in NMHC concentration may play an important role in the growth of freshly nucleated particles at the urban site. The burst of nucleation mode particles at the forest site typically started around noon (10:30–14:30 LT), which was 3–4 h later than that at the urban site. Interestingly, at the forest site the burst of nucleation mode particles usually started when air masses originating from urban Sapporo arrived at the forest site. The present study indicates that the inflow of these urban air masses acted as a trigger for the initiation of the burst of nucleation mode particles in the deciduous forest.

scholarly journals Quantifying the hygroscopic properties of cyclodextrin containing aerosol for drug delivery to the lungs

2020 ◽  
Vol 22 (20) ◽  
pp. 11327-11336
Author(s):  
C. P. F. Day ◽  
A. Miloserdov ◽  
K. Wildish-Jones ◽  
E. Pearson ◽  
A. E. Carruthers
Keyword(s):  
Drug Delivery ◽  
Growth Factor ◽  
Hygroscopic Growth ◽  
Vapour Sorption ◽  
Hygroscopic Properties ◽  
Dynamic Vapour Sorption

The hygroscopic growth factor for individual aqueous 2-hydroxypropyl β-cyclodextrin droplets has been measured and compared with dynamic vapour sorption measurements.

scholarly journals Design and Application of an Unattended Multifunctional H-TDMA System

2013 ◽  
Vol 30 (6) ◽  
pp. 1136-1148 ◽  
Author(s):  
Haobo Tan ◽  
Hanbing Xu ◽  
Qilin Wan ◽  
Fei Li ◽  
Xuejiao Deng ◽  
...  
Keyword(s):  
Particle Size ◽  
Growth Factor ◽  
Cloud Condensation Nuclei ◽  
Polystyrene Latex ◽  
Hygroscopic Growth ◽  
Differential Mobility Analyzer ◽  
Differential Mobility ◽  
China Meteorological Administration ◽  
Hygroscopic Properties ◽  
Calibration Methods

Abstract The hygroscopic properties of aerosols have a significant impact on aerosol particle number size distributions (PNSD), formation of cloud condensation nuclei, climate forcing, and atmospheric visibility, as well as human health. To allow for the observation of the hygroscopic growth of aerosols with long-term accuracy, an unattended multifunctional hygroscopicity-tandem differential mobility analyzer (H-TDMA) system was designed and built by the Institute of Tropical and Marine Meteorology (ITMM), China Meteorological Administration (CMA), in Guangzhou, China. The system is capable of measuring dry and wet PNSD, hygroscopic growth factor by particle size, and mixing states. This article describes in detail the working principles, components, and calibration methods of the system. Standard polystyrene latex (PSL) spheres with five different diameters were chosen to test the system’s precision and accuracy of particle size measurement. Ammonium sulfate was used to test the hygroscopic response of the system for accurate growth factor measurement. The test results show that the deviation of the growth factor measured by the system is within a scope of −0.01 to −0.03 compared to Köhler theoretical curves. Results of temperature and humidity control performance tests indicate that the system is robust. An internal temperature gradient of less than 0.2 K for a second differential mobility analyzer (DMA2) makes it possible to reach a set-point relative humidity (RH) value of 90% and with a standard deviation of ±0.44%, sufficient for unattended field observation.

scholarly journals Hygroscopic properties of the Paris urban aerosol in relation to its chemical composition

2014 ◽  
Vol 14 (2) ◽  
pp. 737-749 ◽  
Author(s):  
K. A. Kamilli ◽  
L. Poulain ◽  
A. Held ◽  
A. Nowak ◽  
W. Birmili ◽  
...  
Keyword(s):  
Growth Factors ◽  
Chemical Composition ◽  
Chemical Properties ◽  
Temporal Variations ◽  
Summation Method ◽  
Urban Site ◽  
Hygroscopic Growth ◽  
Differential Mobility ◽  
Hygroscopic Properties ◽  
Particle Sizer

Abstract. Aerosol hygroscopic growth factors and chemical properties were measured as part of the MEGAPOLI "Megacities Plume Case Study" at the urban site Laboratoire d'Hygiène de la Ville de Paris (LHVP) in the city center of Paris from June to August 2009, and from January to February 2010. Descriptive hygroscopic growth factors (DGF) were derived in the diameter range from 25 to 350 nm at relative humidities of 30, 55, 75, and 90% by applying the summation method on humidified and dry aerosol size distributions measured simultaneously with a humidified differential mobility particle sizer (HDMPS) and a twin differential mobility particle sizer (TDMPS). For 90% relative humidity, the DGF varied from 1.06 to 1.46 in summer, and from 1.06 to 1.66 in winter. Temporal variations in the observed mean DGF could be well explained with a simple growth model based on the aerosol chemical composition measured by aerosol mass spectrometry (AMS) and black carbon photometry (MAAP). In particular, good agreement was observed when sulfate was the predominant inorganic factor. A clear overestimation of the predicted growth factor was found when the nitrate mass concentration exceeded values of 10 μg m−3, e.g., during winter.

scholarly journals Size distribution and hygroscopic properties of aerosol particles from dry-season biomass burning in Amazonia

2006 ◽  
Vol 6 (2) ◽  
pp. 471-491 ◽  
Author(s):  
J. Rissler ◽  
A. Vestin ◽  
E. Swietlicki ◽  
G. Fisch ◽  
J. Zhou ◽  
...  
Keyword(s):  
Growth Factors ◽  
Biomass Burning ◽  
Particle Number ◽  
Size Distributions ◽  
Hygroscopic Growth ◽  
Differential Mobility ◽  
Accumulation Mode ◽  
Hygroscopic Properties ◽  
Particle Sizer ◽  
Aitken Mode

Abstract. Aerosol particle number size distributions and hygroscopic properties were measured at a pasture site in the southwestern Amazon region (Rondonia). The measurements were performed 11 September-14 November 2002 as part of LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia - SMOke aerosols, Clouds, rainfall and Climate), and cover the later part of the dry season (with heavy biomass burning), a transition period, and the onset of the wet period. Particle number size distributions were measured with a DMPS (Differential Mobility Particle Sizer, 3-850nm) and an APS (Aerodynamic Particle Sizer), extending the distributions up to 3.3 µm in diameter. An H-TDMA (Hygroscopic Tandem Differential Mobility Analyzer) measured the hygroscopic diameter growth factors (Gf) at 90% relative humidity (RH), for particles with dry diameters (dp) between 20-440 nm, and at several occasions RH scans (30-90% RH) were performed for 165nm particles. These data provide the most extensive characterization of Amazonian biomass burning aerosol, with respect to particle number size distributions and hygroscopic properties, presented until now. The evolution of the convective boundary layer over the course of the day causes a distinct diel variation in the aerosol physical properties, which was used to get information about the properties of the aerosol at higher altitudes. The number size distributions averaged over the three defined time periods showed three modes; a nucleation mode with geometrical median diameters (GMD) of ~12 nm, an Aitken mode (GMD=61-92 nm) and an accumulation mode (GMD=128-190 nm). The two larger modes were shifted towards larger GMD with increasing influence from biomass burning. The hygroscopic growth at 90% RH revealed a somewhat external mixture with two groups of particles; here denoted nearly hydrophobic (Gf~1.09 for 100 nm particles) and moderately hygroscopic (Gf~1.26). While the hygroscopic growth factors were surprisingly similar over the periods, the number fraction of particles belonging to each hygroscopic group varied more, with the dry period aerosol being more dominated by nearly hydrophobic particles. As a result the total particle water uptake rose going into the cleaner period. The fraction of moderately hygroscopic particles was consistently larger for particles in the accumulation mode compared to the Aitken mode for all periods. Scanning the H-TDMA over RH (30-90% RH) showed no deliquescence behavior. A parameterization of both Gf(RH) and Gf(dp), is given.

scholarly journals Hygroscopic properties and mixing state of aerosol measured at the high altitude site Puy de Dôme (1465 m a.s.l.), France

2014 ◽  
Vol 14 (5) ◽  
pp. 6759-6802
Author(s):  
H. Holmgren ◽  
K. Sellegri ◽  
M. Hervo ◽  
C. Rose ◽  
E. Freney ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Particle Size ◽  
Growth Factor ◽  
High Altitude ◽  
Hygroscopic Growth ◽  
Mixing State ◽  
Air Mass ◽  
Hygroscopic Properties ◽  
Seasonal And Diurnal Variations ◽  
Mass Type

Abstract. A Hygroscopicity Tandem Differential Mobility Analyzer (HTDMA) was used to evaluate the hygroscopic properties of aerosol particles measured at the Puy de Dôme research station in central France from September 2008 to December 2012. This high-altitude site is ideally situated to allow for both the upper part of the planetary boundary layer and the lower free troposphere to be sampled. The aim of the study is to investigate both the influence of year-to-year, seasonal, and diurnal cycles, as well as the influence of air mass type on particle hygroscopicity and mixing state. Results show that particle hygroscopicity increases with particle size and depends both on air mass type and on season. Average growth factor values are lowest in winter (1.21 ± 0.13, 1.23 ± 0.18 and 1.38 ± 0.25 for 25, 50 and 165 nm particles, respectively) and highest in autumn (1.27 ± 0.11, 1.32 ± 0.12 and 1.49 ± 0.15 for 25, 50 and 165 nm particles, respectively). Particles are generally more hygroscopic at night than during the day. The seasonal and diurnal variations are likely to be strongly influenced by boundary layer dynamics. Furthermore, particles originating from oceanic and continental regions tend to be more hygroscopic than those measured in African and local air masses. The high hygroscopicity of marine aerosol may be explained by large proportions of inorganic aerosol and sea salts, and it is speculated that continental particles are more hygroscopic than local and African ones due to ageing of fresh combustion aerosol. Aerosol measured at the Puy de Dôme display a high degree of external mixing, and hygroscopic growth spectra can be divided into three different hygroscopic modes: a less hygroscopic mode (GF < 1.3), a hygroscopic mode (GF 1.3–1.7) and a more hygroscopic mode (GF > 1.7). The majority of particles measured can be classified as being in either the less hygroscopic mode or the hygroscopic mode, and only few of them have more hygroscopic properties. The degree of external mixing, evaluated as the fraction of time when the aerosol is found with two or more populations with different hygroscopic properties, is found to increase with particle size (average yearly values are 22, 33 and 49% for 25, 50, and 165 nm particles, respectively). The degree of external mixing is more sensitive to season than to air mass type, and it is higher in the cold seasons than in the warm seasons. This study gathers the results from one of the longest data sets of hygroscopic growth factor measurements to date, allowing a statistically relevant hygroscopic growth parameterization to be determined as a function of both air mass type and season.

scholarly journals Development of an H-TDMA for long-term unattended measurement of the hygroscopic properties of atmospheric aerosol particles

2009 ◽  
Vol 2 (2) ◽  
pp. 1057-1073
Author(s):  
E. Nilsson ◽  
E. Swietlicki ◽  
S. Sjogren ◽  
J. Löndahl ◽  
M. Nyman ◽  
...  
Keyword(s):  
Growth Factor ◽  
Ammonium Sulphate ◽  
Atmospheric Aerosol ◽  
Aerosol Particles ◽  
Temperature Stability ◽  
Hygroscopic Growth ◽  
Hygroscopic Properties ◽  
Atmospheric Aerosol Particles ◽  
New Generation

Abstract. A new hygroscopic tandem differential mobility analyzer (H-TDMA) has been constructed at Lund University within the frameworks of the EU FP6 Infrastructure Project EUSAAR (http://www.eusaar.org/). The aim of this coordinated H-TDMA development is to design and evaluate a new generation of H-TDMAs that are capable of conducting long term measurements of the hygroscopic growth and state of mixing of sub-micrometer atmospheric aerosol particles at the EUSAAR aerosol super-sites across Europe. The H-TDMA constructed for this project has been validated with respect to hygroscopic growth factor, stability of relative humidity (RH), temperature stability and its ability to operate unattended for longer periods of time. When measuring growth factors of ammonium sulphate, the new H-TDMA system was found to measure within a growth factor deviation of ±0.05 compared to previously recorded data by Tang et al. (1994). The long term RH of the system has been found stable at 90.0% with a standard deviation of ±0.23% and an average temperature variability of the second DMA less than ±0.1 K. Daily automated ammonium sulphate measurements have validated the ambient measurements. The instrument is operated at the EMEP/EUSAAR background station Vavihill in the southern part of Sweden.

scholarly journals Particle hygroscopicity and its link to chemical composition in the urban atmosphere of Beijing, China, during summertime

2016 ◽  
Vol 16 (2) ◽  
pp. 1123-1138 ◽  
Author(s):  
Z. J. Wu ◽  
J. Zheng ◽  
D. J. Shang ◽  
Z. F. Du ◽  
Y. S. Wu ◽  
...  
Keyword(s):  
Particle Size ◽  
Chemical Composition ◽  
Growth Factor ◽  
Mass Concentration ◽  
Particle Formation ◽  
High Time Resolution ◽  
New Particle Formation ◽  
Hygroscopic Growth ◽  
Hygroscopic Properties ◽  
Beijing China

Abstract. Simultaneous measurements of particle number size distribution, particle hygroscopic properties, and size-resolved chemical composition were made during the summer of 2014 in Beijing, China. During the measurement period, the mean hygroscopicity parameters (κs) of 50, 100, 150, 200, and 250 nm particles were respectively 0.16  &amp;pm;  0.07, 0.19  &amp;pm;  0.06, 0.22  &amp;pm;  0.06, 0.26  &amp;pm;  0.07, and 0.28  &amp;pm;  0.10, showing an increasing trend with increasing particle size. Such size dependency of particle hygroscopicity was similar to that of the inorganic mass fraction in PM1. The hydrophilic mode (hygroscopic growth factor, HGF  >  1.2) was more prominent in growth factor probability density distributions and its dominance of hydrophilic mode became more pronounced with increasing particle size. When PM2.5 mass concentration was greater than 50 μg m−3, the fractions of the hydrophilic mode for 150, 250, and 350 nm particles increased towards 1 as PM2.5 mass concentration increased. This indicates that aged particles dominated during severe pollution periods in the atmosphere of Beijing. Particle hygroscopic growth can be well predicted using high-time-resolution size-resolved chemical composition derived from aerosol mass spectrometer (AMS) measurements using the Zdanovskii–Stokes–Robinson (ZSR) mixing rule. The organic hygroscopicity parameter (κorg) showed a positive correlation with the oxygen to carbon ratio. During the new particle formation event associated with strongly active photochemistry, the hygroscopic growth factor or κ of newly formed particles is greater than for particles with the same sizes not during new particle formation (NPF) periods. A quick transformation from external mixture to internal mixture for pre-existing particles (for example, 250 nm particles) was observed. Such transformations may modify the state of the mixture of pre-existing particles and thus modify properties such as the light absorption coefficient and cloud condensation nuclei activation.

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