scholarly journals A phenomenology of new particle formation (NPF) at 13 European sites

2021 ◽  
Vol 21 (15) ◽  
pp. 11905-11925
Author(s):  
Dimitrios Bousiotis ◽  
Francis D. Pope ◽  
David C. S. Beddows ◽  
Manuel Dall'Osto ◽  
Andreas Massling ◽  
...  

Abstract. New particle formation (NPF) events occur almost everywhere in the world and can play an important role as a particle source. The frequency and characteristics of NPF events vary spatially, and this variability is yet to be fully understood. In the present study, long-term particle size distribution datasets (minimum of 3 years) from 13 sites of various land uses and climates from across Europe were studied, and NPF events, deriving from secondary formation and not traffic-related nucleation, were extracted and analysed. The frequency of NPF events was consistently found to be higher at rural background sites, while the growth and formation rates of newly formed particles were higher at roadsides (though in many cases differences between the sites were small), underlining the importance of the abundance of condensable compounds of anthropogenic origin found there. The growth rate was higher in summer at all rural background sites studied. The urban background sites presented the highest uncertainty due to greater variability compared to the other two types of site. The origin of incoming air masses and the specific conditions associated with them greatly affect the characteristics of NPF events. In general, cleaner air masses present higher probability for NPF events, while the more polluted ones show higher growth rates. However, different patterns of NPF events were found, even at sites in close proximity (< 200 km), due to the different local conditions at each site. Region-wide events were also studied and were found to be associated with the same conditions as local events, although some variability was found which was associated with the different seasonality of the events at two neighbouring sites. NPF events were responsible for an increase in the number concentration of ultrafine particles of more than 400 % at rural background sites on the day of their occurrence. The degree of enhancement was less at urban sites due to the increased contribution of other sources within the urban environment. It is evident that, while some variables (such as solar radiation intensity, relative humidity, or the concentrations of specific pollutants) appear to have a similar influence on NPF events across all sites, it is impossible to predict the characteristics of NPF events at a site using just these variables, due to the crucial role of local conditions.

2020 ◽  
Author(s):  
Dimitrios Bousiotis ◽  
Francis D. Pope ◽  
David C. Beddows ◽  
Manuel Dall’Osto ◽  
Andreas Massling ◽  
...  

Abstract. New particle formation (NPF) events occur almost everywhere in the world and can play an important role as a particle source. The frequency and characteristics of NPF events vary spatially and this variability is yet to be fully understood. In the present study, long term particle size distribution datasets (minimum of three years) from thirteen sites of various land uses and climates from across Europe were studied and NPF events, deriving from secondary formation and not traffic related nucleation, were extracted and analysed. The frequency of NPF events was consistently found to be higher at rural background sites, while the growth and formation rates of newly formed particles were higher at roadsides, underlining the importance of the abundance of condensable compounds of anthropogenic origin found there. The growth rate was higher in summer at all rural background sites studied. The urban background sites presented the highest uncertainty due to greater variability compared to the other two types of site. The origin of incoming air masses and the specific conditions associated with them greatly affect the characteristics of NPF events. In general, cleaner air masses present higher probability for NPF events, while the more polluted ones show higher growth rates. However, different patterns of NPF events were found even at sites in close proximity (


2018 ◽  
Author(s):  
Dimitrios Bousiotis ◽  
Manuel Dall’Osto ◽  
David C. S. Beddows ◽  
Francis D. Pope ◽  
Roy M. Harrison

Abstract. NPF events have different patterns of development depending on the conditions of the area in which they occur. In this study, NPF events occurring at three sites of differing characteristics (rural Harwell (HAR), urban background North Kensington (NK), urban roadside Marylebone Road (MR), London, UK) were studied (seven years of data). The different atmospheric conditions in each study area not only have an effect on the frequency of the events, but also affect their development. The frequency of NPF events is similar at the rural and urban background locations (about 7 % of days), with a high proportion of events occurring at both sites on the same day (45 %). The frequency of NPF events at the urban roadside site is slightly less (6 % of days), and higher particle growth rates (average 5.5 nm h−1 at MR compared to 3.4 nm h−1 and 4.2 nm h−1 at HAR and NK respectively) must result from rapid gas to particle conversion of traffic-generated pollutants. A general pattern is found in which the condensation sink increases with the degree of pollution of the site, but this is counteracted by increased particle growth rates at the more polluted location. A key finding of this study is that the role of the urban environment leads to an increment of 20 % in N16–20 nm in the urban background compared to that of the rural area in NPF events occurring at both sites. The relationship of the origin of incoming air masses is also considered and an association of regional events with cleaner air masses is found. Due to lower availability of condensable species, NPF events that are associated with cleaner atmospheric conditions have lower growth rates of the newly formed particles. The decisive effect of the condensation sink in the development of NPF events and the survivability of the newly formed particles is underlined, and influences the overall contribution of NPF events to the number of ultrafine particles in an area. The other key factor identified by this study is the important role that urban pollution plays in new particle formation events.


2019 ◽  
Vol 19 (16) ◽  
pp. 10537-10555 ◽  
Author(s):  
Simo Hakala ◽  
Mansour A. Alghamdi ◽  
Pauli Paasonen ◽  
Ville Vakkari ◽  
Mamdouh I. Khoder ◽  
...  

Abstract. Atmospheric aerosols have significant effects on human health and the climate. A large fraction of these aerosols originates from secondary new particle formation (NPF), where atmospheric vapors form small particles that subsequently grow into larger sizes. In this study, we characterize NPF events observed at a rural background site of Hada Al Sham (21.802∘ N, 39.729∘ E), located in western Saudi Arabia, during the years 2013–2015. Our analysis shows that NPF events occur very frequently at the site, as 73 % of all the 454 classified days were NPF days. The high NPF frequency is likely explained by the typically prevailing conditions of clear skies and high solar radiation, in combination with sufficient amounts of precursor vapors for particle formation and growth. Several factors suggest that in Hada Al Sham these precursor vapors are related to the transport of anthropogenic emissions from the coastal urban and industrial areas. The median particle formation and growth rates for the NPF days were 8.7 cm−3 s−1 (J7 nm) and 7.4 nm h−1 (GR7−12 nm), respectively, both showing highest values during late summer. Interestingly, the formation and growth rates increase as a function of the condensation sink, likely reflecting the common anthropogenic sources of NPF precursor vapors and primary particles affecting the condensation sink. A total of 76 % of the NPF days showed an unusual progression, where the observed diameter of the newly formed particle mode started to decrease after the growth phase. In comparison to most long-term measurements, the NPF events in Hada Al Sham are exceptionally frequent and strong both in terms of formation and growth rates. In addition, the frequency of the decreasing mode diameter events is higher than anywhere else in the world.


2020 ◽  
Vol 20 (10) ◽  
pp. 5911-5922 ◽  
Author(s):  
Hing Cho Cheung ◽  
Charles Chung-Kuang Chou ◽  
Celine Siu Lan Lee ◽  
Wei-Chen Kuo ◽  
Shuenn-Chin Chang

Abstract. The chemical composition of fine particulate matter (PM2.5), the size distribution and number concentration of aerosol particles (NCN), and the number concentration of cloud condensation nuclei (NCCN) were measured at the northern tip of Taiwan during an intensive observation experiment from April 2017 to March 2018. The parameters of aerosol hygroscopicity (i.e., activation ratio, activation diameter and kappa of CCN) were retrieved from the measurements. Significant variations were found in the hygroscopicity of aerosols (kappa – κ – of 0.18–0.56, for water vapor supersaturation – SS – of 0.12 %–0.80 %), which were subject to various pollution sources, including aged air pollutants originating in eastern and northern China and transported by the Asian continental outflows and fresh particles emitted from local sources and distributed by land–sea breeze circulations as well as produced by processes of new particle formation (NPF). Cluster analysis was applied to the back trajectories of air masses to investigate their respective source regions. The results showed that aerosols associated with Asian continental outflows were characterized by lower NCN and NCCN values and by higher kappa values of CCN, whereas higher NCN and NCCN values with lower kappa values of CCN were observed in the aerosols associated with local air masses. Besides, it was revealed that the kappa value of CCN exhibited a decrease during the early stage of an event of new particle formation, which turned to an increasing trend over the later period. The distinct features in the hygroscopicity of aerosols were found to be consistent with the characteristics in the chemical composition of PM2.5. This study has depicted a clear seasonal characteristic of hygroscopicity and CCN activity under the influence of a complex mixture of pollutants from different regional and/or local pollution sources. Nevertheless, the mixing state and chemical composition of the aerosols critically influence the aerosol hygroscopicity, and further investigations are necessary to elucidate the atmospheric processing involved in the CCN activation in coastal areas.


2019 ◽  
Vol 19 (11) ◽  
pp. 7595-7608 ◽  
Author(s):  
Eunho Jang ◽  
Ki-Tae Park ◽  
Young Jun Yoon ◽  
Tae-Wook Kim ◽  
Sang-Bum Hong ◽  
...  

Abstract. Marine biota is an important source of atmospheric aerosol particles in the remote marine atmosphere. However, the relationship between new particle formation and marine biota is poorly quantified. Long-term observations (from 2009 to 2016) of the physical properties of atmospheric aerosol particles measured at the Antarctic Peninsula (King Sejong Station; 62.2∘ S, 58.8∘ W) and satellite-derived estimates of the biological characteristics were analyzed to identify the link between new particle formation and marine biota. New particle formation events in the Antarctic atmosphere showed distinct seasonal variations, with the highest values occurring when the air mass originated from the ocean domain during the productive austral summer (December, January and February). Interestingly, new particle formation events were more frequent in the air masses that originated from the Bellingshausen Sea than in those that originated from the Weddell Sea. The monthly mean number concentration of nanoparticles (2.5–10 nm in diameter) was >2-fold higher when the air masses passed over the Bellingshausen Sea than the Weddell Sea, whereas the biomass of phytoplankton in the Weddell Sea was more than ∼70 % higher than that of the Bellingshausen Sea during the austral summer period. Dimethyl sulfide (DMS) is of marine origin and its oxidative products are known to be one of the major components in the formation of new particles. Both satellite-derived estimates of the biological characteristics (dimethylsulfoniopropionate, DMSP; precursor of DMS) and phytoplankton taxonomic composition and in situ methanesulfonic acid (84 daily measurements during the summer period in 2013 and 2014) analysis revealed that DMS(P)-rich phytoplankton were more dominant in the Bellingshausen Sea than in the Weddell Sea. Furthermore, the number concentration of nanoparticles was positively correlated with the biomass of phytoplankton during the period when DMS(P)-rich phytoplankton predominate. These results indicate that oceanic DMS emissions could play a key role in the formation of new particles; moreover, the taxonomic composition of phytoplankton could affect the formation of new particles in the Antarctic Ocean.


2010 ◽  
Vol 10 (4) ◽  
pp. 11361-11399 ◽  
Author(s):  
J. Boulon ◽  
K. Sellegri ◽  
H. Venzac ◽  
D. Picard ◽  
E. Weingartner ◽  
...  

Abstract. Aerosol nucleation is an important source of atmospheric particles which have an effect both on the climatic system and on human health. The new particle formation (NPF) process is an ubiquitous phenomenon, yet poorly understood despite the many studies performed on this topic using various approaches (observation, experimentation in smog chambers and modeling). In this work, we investigate the formation of secondary charged aerosols and its climatology at Jungfraujoch, a high altitude site in Swiss Alps (3580 m a.s.l.). Charged particles and clusters (0.5–1.8 nm) were measured within the EUCAARI program from April 2008 to April 2009 and allowed the detection of nucleation events. We found that the aerosol concentration, which is dominated by cluster size class, shows a strong diurnal pattern and that the aerosol size distribution and concentration are strongly influenced by the presence of clouds either during daytime or nighttime conditions. New particle formation events have been investigated and it appears that new particle formation occurs 17.5% of measured days and that the nucleation frequency is strongly linked to air mass origin and path and negatively influenced by cloud presence. In fact, we show that NPF events depend on the occurrence of high concentration VOCs air masses which allowed clusters growing by condensation of organic vapors rather than nucleation of new clusters. Furthermore, the contribution of ions to nucleation process was studied and we found that ion-mediated nucleation (IMN) contribute to 26% of the total nucleation so that ions play an important role in the new particle formation and growth at Jungfraujoch.


2014 ◽  
Vol 14 (19) ◽  
pp. 26463-26494 ◽  
Author(s):  
M. Brines ◽  
M. Dall'Osto ◽  
D. C. S. Beddows ◽  
R. M. Harrison ◽  
F. Gómez-Moreno ◽  
...  

Abstract. Road traffic emissions are often considered the main source of ultrafine particles (UFP, diameter smaller than 100 nm) in urban environments. However, recent studies have shown that – in southern European urban regions at least – new particle formation events can also contribute to UFP. In order to quantify such events we systematically studied four cities with a Mediterranean climate: Barcelona, Madrid, Rome and Los Angeles. The city of Brisbane is also included in our study due to its similar climate. Five long term datasets (from 3 months to 2 years) of fine and ultrafine particle number size distributions (measured by SMPS, Scanning Mobility Particle Sizer) were analysed. By applying k-Means clustering analysis, we categorized the collected aerosol size distributions in four main classes: "Traffic" (prevailing 41–63% of the time), "Background Pollution" (6–53%), "Nucleation" (6–33%) and "Specific case" (7–20%) the latter being site specific. The daily variation of the average UFP concentrations for a typical nucleation day at each site revealed a similar pattern for all cities, with three distinct particle bursts. A morning and an evening spike reflected traffic rush hours, whereas a third one at midday showed new particle formation events. This work shows that the average occurrence of particle size spectra dominated by new particle formation events was 18% of the time, showing the importance of this process as a source of UFP in the Mediterranean urban atmosphere. Furthermore, in a number of the studied cities, particle number concentration averaged daily profiles for the whole study periods clearly showed the same three particle bursts. This reveals nucleation events as a relevant contributor to the average daily urban exposure to UFP in Mediterranean urban environments.


2005 ◽  
Vol 5 (6) ◽  
pp. 11929-11963 ◽  
Author(s):  
M. Komppula ◽  
S.-L. Sihto ◽  
H. Korhonen ◽  
H. Lihavainen ◽  
V.-M. Kerminen ◽  
...  

Abstract. This study covers four years of aerosol number size distribution data from Pallas and Värriö sites 250 km apart from each other in Northern Finland and compares new particle formation events between these sites. In eastern air masses almost all events were observed to start earlier at the eastern station Värriö, whereas in western air masses most of the events were observed to start earlier at the western station Pallas. This demonstrates that particle formation in a certain air mass type depends not only on the diurnal variation of the parameters causing the phenomenon (such as photochemistry) but also on some properties carried by the air mass itself. The correlation in growth rates between the two sites was relatively good, which suggests that the amount of condensable vapour causing the growth must have been at about the same level in both sites. The value of condensation sink was frequently much higher at the downwind station. It seems that secondary particle formation related to biogenic sources dominate in many cases over the particle sinks during the air mass transport between the sites. Two cases of transport from Pallas to Värriö were further analysed with an aerosol dynamics model. The model was able to reproduce the observed nucleation events 250 km down-wind at Värriö but revealed some differences between the two cases. The simulated nucleation rates were in both cases similar but the organic concentration profiles that best reproduced the observations were different in the two cases indicating that divergent formation reactions may dominate under different conditions. The simulations also suggested that organic compounds were the main contributor to new particle growth, which offers a tentative hypothesis to the distinct features of new particles at the two sites: Air masses arriving from Atlantic Ocean typically spent approximately only ten hours over land before arriving at Pallas, and thus the time for the organic vapours to accumulate in the air and to interact with the particles is relatively short. This can lead to low nucleation mode growth rates and even to suppression of detectable particle formation event due to efficient scavenging of newly formed clusters, as was observed in the case studies.


2018 ◽  
Author(s):  
Eunho Jang ◽  
Ki-Tae Park ◽  
Young Jun Yoon ◽  
Tae-Wook Kim ◽  
Sang-Bum Hong ◽  
...  

Abstract. Marine biota is an important source of atmospheric aerosols in the remote marine atmosphere. Long-term observations (from 2009 to 2016) of the physical properties of atmospheric aerosol particles measured at the Antarctic Peninsula (King Sejong Station; 62.2° S, 58.8° W) and satellite-derived estimates of the biological characteristics were analyzed to identify the link between new particle formation and marine biota. New particle formation events in the Antarctic atmosphere showed distinct seasonal variations, with the highest values occurring during austral summer (December, January and February). Interestingly, new particle formation events were more frequent in the air masses that originated from the Bellingshausen Sea than in those that originated from the Weddell Sea. The monthly mean number concentration of nanoparticles (2.5–10 nm in diameter) was > 2-fold when the air masses passed over the Bellingshausen Sea than the Weddell Sea, whereas the biomass of phytoplankton in the Weddell Sea was more than ~ 70 % higher than that of the Bellingshausen Sea during the austral summer period. Dimethyl sulfide (DMS) is of marine origin and its oxidative products are known to be one of the major components in the formation of new particles. Both satellite-derived estimates of the biological characteristics (dimethylsulfoniopropionate (DMSP; precursor of DMS) and phytoplankton taxonomic composition) and in situ methanesulfonic acid (MSA; oxidation product of DMS) analysis revealed that DMS(P)-rich phytoplankton were more dominant in the Bellingshausen Sea than in the Weddell Sea. Furthermore, the number concentration of nanoparticles was positively correlated with the biomass of phytoplankton during the period when DMS(P)-rich phytoplankton predominate. These results indicate that oceanic DMS emissions could play a key role in the formation of new particles; moreover, the taxonomic composition of phytoplankton could affect the formation of secondary organic aerosols in the Antarctic Ocean.


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