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 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 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 First long-term study of particle number size distributions and new particle formation events of regional aerosol in the North China Plain

2010 ◽  
Vol 10 (10) ◽  
pp. 25205-25242 ◽  
Author(s):  
X. J. Shen ◽  
J. Y. Sun ◽  
Y. M. Zhang ◽  
B. Wehner ◽  
A. Nowak ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Particle Number ◽  
Particle Formation ◽  
Mean Value ◽  
Size Distributions ◽  
New Particle Formation ◽  
Air Masses ◽  
Nucleation Mode ◽  
The North

Abstract. Atmospheric particle number size distributions (size range 0.003–10 μm) were measured between March 2008 and August 2009 at Shangdianzi (SDZ), a rural research station in the North China Plain. These measurements were made in an attempt to better characterize the tropospheric background aerosol in Northern China, one of the currently more polluted regions of the globe. The mean particle number concentrations of the total aerosol, as well as the nucleation, Aitken and accumulation modes were determined to 1.2±0.9×104, 3.6±7.9×103, 4.4±3.4×103 and 3.5±2.8×103 cm−3, respectively. A general finding is that the particle number concentrations were higher during spring compared to the other seasons. The air mass origin had an important effect on the particle number concentration and new particle formation events. Air masses from northwest (i.e. inner Asia) showed the highest concentrations of nucleation mode particles, while southeasterly air masses showed the highest concentrations of accumulation mode particles. Significant diurnal variations in particle number were observed, which could be linked to new particle formation events, i.e. gas-to-particle conversion. During particle formation events, the number concentration of the nucleation mode rose up to maximum values of 104 cm−3. New particle formation events were observed on 36% of the measurement days. The formation rate ranged between 0.7 and 72.7 cm−3 s−1, with a mean value of 8.0 cm−3 s−1. The values of the nucleation mode growth rate ranged between 0.3 and 14.5 nm h−1, with a mean value of 4.3 nm h−1. It is an essential observation that on many occasions, the nucleation mode was able to grow into the size of cloud condensation nuclei (CCN) within a matter of several hours. Furthermore, the new particle formation were usually followed by a measurable increase in total particle mass concentration and extinction coefficient, indicative of a high abundance of condensable vapors in the atmosphere under study.

scholarly journals Regional New Particle Formation over the Eastern Mediterranean and Middle East

Atmosphere ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 13
Author(s):  
Panayiotis Kalkavouras ◽  
Aikaterini BougiatiotI ◽  
Tareq Hussein ◽  
Nikos Kalivitis ◽  
Iasonas Stavroulas ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Particle Number ◽  
Eastern Mediterranean ◽  
Particle Formation ◽  
Urban Environments ◽  
Urban Site ◽  
Simultaneous Occurrence ◽  
New Particle Formation ◽  
Air Masses ◽  
Background Site

Atmospheric new particle formation (NPF) events taking place over large distances between locations, featuring similar characteristics, have been the focus of studies during the last decade. The exact mechanism which triggers NPF still remains indefinable, so are the circumstances under which simultaneous occurrence of such events take place in different environments, let alone in environments which are parted by over 1200 km. In this study, concurrent number size distribution measurements were conducted in the urban environments of Athens (Greece) and Amman (Jordan) as well as the regional background site of Finokalia, Crete, all located within a distance of almost 1300 km for a 6-month period (February–July 2017). During the study period Athens and Finokalia had similar occurrence of NPF (around 20%), while the occurrence in Amman was double. When focusing on the dynamic characteristics at each site, it occurs that formation and growth rates at Amman are similar to those at Finokalia, while lower values in Athens can be ascribed to a higher pre-existing particle number at this urban site. By comparing common NPF events there are 5 concomitant days between all three sites, highly related to air masses origin. Additionally, for another 19 days NPF takes place simultaneously between Finokalia and Amman, which also share common meteorological characteristics, adding to a total of 60% out of 41 NPF events observed at Finokalia, also simultaneously occurring in Amman.

scholarly journals First long-term study of particle number size distributions and new particle formation events of regional aerosol in the North China Plain

2011 ◽  
Vol 11 (4) ◽  
pp. 1565-1580 ◽  
Author(s):  
X. J. Shen ◽  
J. Y. Sun ◽  
Y. M. Zhang ◽  
B. Wehner ◽  
A. Nowak ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Particle Number ◽  
Particle Formation ◽  
Mean Value ◽  
Number Concentration ◽  
New Particle Formation ◽  
Air Masses ◽  
Nucleation Mode ◽  
The North

Abstract. Atmospheric particle number size distributions (size range 0.003–10 μm) were measured between March 2008 and August 2009 at Shangdianzi (SDZ), a rural research station in the North China Plain. These measurements were made in an attempt to better characterize the tropospheric background aerosol in Northern China. The mean particle number concentrations of the total particle, as well as the nucleation, Aitken, accumulation and coarse mode were determined to be 1.2 ± 0.9 × 104, 3.6 ± 7.9 × 103, 4.4 ± 3.4 × 103, 3.5 ± 2.8 × 103 and 2 ± 3 cm−3, respectively. A general finding was that the particle number concentration was higher during spring compared to the other seasons. The air mass origin had an important effect on the particle number concentration and new particle formation events. Air masses from northwest (i.e. inner Asia) favored the new particle formation events, while air masses from southeast showed the highest particle mass concentration. Significant diurnal variations in particle number were observed, which could be linked to new particle formation events, i.e. gas-to-particle conversion. During particle formation events, the number concentration of the nucleation mode rose up to maximum value of 104 cm−3. New particle formation events were observed on 36% of the effective measurement days. The formation rate ranged from 0.7 to 72.7 cm−3 s−1, with a mean value of 8.0 cm−3 s−1. The value of the nucleation mode growth rate was in the range of 0.3–14.5 nm h−1, with a mean value of 4.3 nm h−1. It was an essential observation that on many occasions the nucleation mode was able to grow into the size of cloud condensation nuclei (CCN) within a matter of several hours. Furthermore, the new particle formation was regularly followed by a measurable increase in particle mass concentration and extinction coefficient, indicative of a high abundance of condensable vapors in the atmosphere under study.

Connection of organics to atmospheric new particle formation and growth at an urban site of Beijing

2015 ◽  
Vol 103 ◽  
pp. 7-17 ◽  
Author(s):  
Z.B. Wang ◽  
M. Hu ◽  
X.Y. Pei ◽  
R.Y. Zhang ◽  
P. Paasonen ◽  
...  
Keyword(s):  
Particle Formation ◽  
Urban Site ◽  
New Particle Formation ◽  
Particle Formation And Growth

scholarly journals Modelling studies of HOMs and their contributions to new particle formation and growth: comparison of boreal forest in Finland and a polluted environment in China

2018 ◽  
Vol 18 (16) ◽  
pp. 11779-11791 ◽  
Author(s):  
Ximeng Qi ◽  
Aijun Ding ◽  
Pontus Roldin ◽  
Zhengning Xu ◽  
Putian Zhou ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Boreal Forest ◽  
Environmental Conditions ◽  
Eastern China ◽  
Particle Growth ◽  
Particle Formation ◽  
Forest Site ◽  
Polluted Environment ◽  
New Particle Formation ◽  
Multifunctional Compounds

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.

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