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 Frequency of new particle formation events in the urban Mediterranean climate

2014 ◽  
Vol 14 (19) ◽  
pp. 26463-26494 ◽  
Author(s):  
M. Brines ◽  
M. Dall'Osto ◽  
D. C. S. Beddows ◽  
R. M. Harrison ◽  
F. Gómez-Moreno ◽  
...  
Keyword(s):  
Los Angeles ◽  
Ultrafine Particles ◽  
Mediterranean Climate ◽  
Particle Number ◽  
Road Traffic ◽  
Particle Formation ◽  
Urban Environments ◽  
Urban Atmosphere ◽  
Size Distributions ◽  
New Particle Formation

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.

scholarly journals New particle formation in coastal New Zealand with a focus on open ocean air masses

2021 ◽  
Author(s):  
Maija Peltola ◽  
Clémence Rose ◽  
Jonathan V. Trueblood ◽  
Sally Gray ◽  
Mike Harvey ◽  
...  
Keyword(s):  
New Zealand ◽  
Particle Concentration ◽  
Particle Number ◽  
Particle Formation ◽  
Open Ocean ◽  
New Particle Formation ◽  
Air Masses ◽  
Wind Speeds ◽  
Marine Air ◽  
Aerosol Properties

Abstract. Even though oceans cover the majority of the Earth, most aerosol measurements are from continental sites. We measured aerosol particle number size distribution at Baring Head, in coastal New Zealand, over a total period of 10 months to study aerosol properties and new particle formation, with a special focus on aerosol formation in open ocean air masses. Particle concentrations were higher in land-influenced air compared to clean marine air in all size classes from sub-10 nm to cloud condensation nuclei sizes. When classifying the particle number size distributions with traditional methods designed for continental sites, new particle formation was observed at the station throughout the year with an average event frequency of 23 %. While most of these traditional event days had some land-influence, we also observed particle growth starting from nucleation mode during 16 % of the data in clean marine air and at least part of this growth was connected to nucleation in the marine boundary layer. Sub-10 nm particles accounted for 29 % of the total aerosol number concentration of particles larger than 1 nm in marine air during the spring. This shows that nucleation in marine air is frequent enough to influence the total particle concentration. Particle formation in land-influenced air was more intense and had on average higher growth rates than what was found for marine air. Particle formation and primary emissions increased particle number concentrations as a function of time spent over land during the first 1–2 days spent over land. After this, nucleation seems to start getting suppressed by the pre-existing particle population, but accumulation mode particle concentration keeps increasing, likely due to primary particle emissions. Further work showed that traditional NPF events were favoured by sunny conditions with low relative humidity and wind speeds. In marine air, formation of sub-10 nm particles was favoured by low temperatures, relative humidity, and wind speeds and could happen even during the night. Our future work will study the mechanisms responsible for particle formation at Baring Head with a focus on different chemical precursor species. This study sheds light on both new particle formation in open ocean air masses coming from the Southern Ocean and local aerosol properties in New Zealand.

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 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 Towards understanding the characteristics of new particle formation in the Eastern Mediterranean

2021 ◽  
Vol 21 (11) ◽  
pp. 9223-9251
Author(s):  
Rima Baalbaki ◽  
Michael Pikridas ◽  
Tuija Jokinen ◽  
Tiia Laurila ◽  
Lubna Dada ◽  
...  
Keyword(s):  
Middle East ◽  
Eastern Mediterranean ◽  
Cloud Condensation Nuclei ◽  
Ultrafine Particle ◽  
Particle Formation ◽  
Meteorological Variables ◽  
Mediterranean Country ◽  
New Particle Formation ◽  
Air Masses ◽  
Desert Dust

Abstract. To quantify the contribution of new particle formation (NPF) to ultrafine particle number and cloud condensation nuclei (CCN) budgets, one has to understand the mechanisms that govern NPF in different environments and its temporal extent. Here, we study NPF in Cyprus, an Eastern Mediterranean country located at the crossroads of three continents and affected by diverse air masses originating from continental, maritime, and desert-dust source areas. We performed 1-year continuous measurements of aerosol particles down to ∼ 1 nm in diameter for the first time in the Eastern Mediterranean and Middle East (EMME) region. These measurements were complemented with trace gas data, meteorological variables, and retroplume analysis. We show that NPF is a very frequent phenomenon at this site and has higher frequencies of occurrence during spring and autumn. NPF events were both of local and regional origin, and the local events occurred frequently during the month with the lowest NPF frequency. Some NPF events exhibited multiple onsets, while others exhibited apparent particle shrinkage in size. Additionally, NPF events were observed during the nighttime and during episodes of high desert-dust loadings. Particle formation rates and growth rates were comparable to those in urban environments, although our site is a rural one. Meteorological variables and trace gases played a role in explaining the intra-monthly variability of NPF events, but they did not explain why summer months had the least NPF frequency. Similarly, pre-existing aerosol loading did not explain the observed seasonality. The months with the least NPF frequency were associated with higher H2SO4 concentrations but lower NO2 concentrations, which is an indicator of anthropogenic influence. Air masses arriving from the Middle East were not observed during these months, which could suggest that precursor vapors important for nucleation and growth are transported to our site from the Middle East. Further comprehensive measurements of precursor vapors are required to prove this hypothesis.

Sign in / Sign up

Export Citation Format

Share Document