Investigation of Particle Number Concentrations and New Particle Formation With Largely Reduced Air Pollutant Emissions at a Coastal Semi‐Urban Site in Northern China

Abstract. Atmospheric new particle formation (NPF) events have attracted increasing attention for their contribution to the global aerosol number budget and therefore their effects on climate, air quality and human health. NPF events are regarded as a regional phenomenon, occurring over a large area. Most observations of NPF events in Beijing and its vicinity were conducted in populated areas, whereas observations of NPF events on mountaintops with low anthropogenic emissions are still rare in China. The spatial variation of NPF event intensity has not been investigated in detail by incorporating both urban areas and mountain measurements in Beijing. Here, we provide NPF event characteristics in summer 2018 and 2019 at urban Beijing and a comparison of NPF event characteristics – NPF event frequency, formation rate and growth rate – by comparing an urban Beijing site and a background mountain site separated by ∼80 km from 14 June to 14 July 2019, as well as giving insights into the connection between both locations. During parallel measurements at urban Beijing and mountain background areas, although the median condensation sink during the first 2 h of the common NPF events was around 0.01 s−1 at both sites, there were notable differences in formation rates between the two locations (median of 5.42 cm−3 s−1 at the urban site and 1.13 cm−3 s−1 at the mountain site during the first 2 h of common NPF events). In addition, the growth rates in the 7–15 nm range for common NPF events at the urban site (median of 7.6 nm h−1) were slightly higher than those at the mountain site (median of 6.5 nm h−1). To understand whether the observed events were connected, we compared air mass trajectories as well as meteorological conditions at both stations. Favorable conditions for the occurrence of regional NPF events were largely affected by air mass transport. Overall, our results demonstrate a clear inhomogeneity of regional NPF within a distance of ∼100 km, possibly due to the discretely distributed emission sources.

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Regional New Particle Formation over the Eastern Mediterranean and Middle East

Atmosphere ◽

10.3390/atmos12010013 ◽

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.

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Variability of air ion concentrations in urban Paris

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-10629-2015 ◽

2015 ◽

Vol 15 (7) ◽

pp. 10629-10676 ◽

Cited By ~ 1

Author(s):

V. N. Dos Santos ◽

E. Herrmann ◽

H. E. Manninen ◽

T. Hussein ◽

J. Hakala ◽

...

Keyword(s):

Particle Number ◽

Cloud Condensation Nuclei ◽

Aerosol Particles ◽

Late Summer ◽

Particle Formation ◽

Urban Site ◽

New Particle Formation ◽

Climatic Effects ◽

Ion Concentrations ◽

Ion Size

Abstract. Air ion concentrations influence new particle formation and consequently the global aerosol an cloud condensation nuclei loads. We aimed to evaluate air ion concentrations and characteristics of new particle formation events (NPF) in the megacity Paris, France (Megapoli project). We measured air ion number size distributions (0.8–42 nm) and fine particle number concentrations (> 6 nm) in an urban site of Paris between 26 June 2009 and 4 October 2010. Air ions were size classified as small (0.8–2 nm), intermediate (2–7 nm) and large (7–20 nm). The media concentrations of small and large ions were 670 and 680 cm−3 respectively (sum of positive an negative polarities) whereas the median concentration of intermediate ions was only 20 cm−3, as these ions were mostly present during new particle formation bursts, i.e. when gas-to-particle conversion produced fresh aerosol particles from gas phase precursors. During peaks in traffic-related particle number, the concentrations of small and intermediate ions decreased whereas the concentrations of large ions increased. Seasonal variations affected the ion population differently, with respect to their size and polarity. NPF was observed in 13 the days, being most frequent in spring and late summer (April, May, July and August). The results also suggest that NPF was favoured on the weekends in comparison to workdays, likely due to the lower levels of condensation sinks in the mornings of weekends (CS weekdays 09:00: 18 × 10−3 s−1; CS weekend 09:00: 8 × 10−3 s−1). The median growth rates (GR) of ions during the NPF events varied between 3–7 nm h−1, increasing with the ion size and being higher on workdays than on weekends for intermediate and large ions. The median GR of small ions on the other hand were rather similar on workdays and weekends. In general, NPF bursts changed the diurnal cycle of particle number, intermediate and large ions by causing an extra peak between 09:00 and 14:00. On average, during the NPF bursts the concentrations of intermediate ions were 8.5–10 times higher than on NPF non-event days, depending on the polarity, and the concentrations of large ions and particles were 1.5–1.8 and 1.2 times higher, respectively. Because the median concentrations of intermediate ions were considerably higher on NPF event days in comparison to NPF non-event days, the results indicate that intermediate ion concentrations could be used as an indication for NPF in Paris. The results suggest that NPF was a source of ions and aerosol particles in Paris and therefore contributed to both air quality degradation and climatic effects, especially in the spring and summer.

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Variability of air ion concentrations in urban Paris

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-13717-2015 ◽

2015 ◽

Vol 15 (23) ◽

pp. 13717-13737 ◽

Cited By ~ 11

Author(s):

V. N. Dos Santos ◽

E. Herrmann ◽

H. E. Manninen ◽

T. Hussein ◽

J. Hakala ◽

...

Keyword(s):

Particle Number ◽

Cloud Condensation Nuclei ◽

Aerosol Particles ◽

Late Summer ◽

Particle Formation ◽

Urban Site ◽

New Particle Formation ◽

Climatic Effects ◽

Ion Concentrations ◽

Ion Size

Abstract. Air ion concentrations influence new particle formation and consequently the global aerosol as potential cloud condensation nuclei. We aimed to evaluate air ion concentrations and characteristics of new particle formation events (NPF) in the megacity of Paris, France, within the MEGAPOLI (Megacities: Emissions, urban, regional and Global Atmospheric Pollution and climate effects, and Integrated tools for assessment and mitigation) project. We measured air ion number size distributions (0.8–42 nm) with an air ion spectrometer and fine particle number concentrations (> 6 nm) with a twin differential mobility particle sizer in an urban site of Paris between 26 June 2009 and 4 October 2010. Air ions were size classified as small (0.8–2 nm), intermediate (2–7 nm), and large (7–20 nm). The median concentrations of small and large ions were 670 and 680 cm−3, respectively, (sum of positive and negative polarities), whereas the median concentration of intermediate ions was only 20 cm−3, as these ions were mostly present during new particle formation bursts, i.e. when gas-to-particle conversion produced fresh aerosol particles from gas phase precursors. During peaks in traffic-related particle number, the concentrations of small and intermediate ions decreased, whereas the concentrations of large ions increased. Seasonal variations affected the ion population differently, with respect to their size and polarity. NPF was observed in 13 % of the days, being most frequent in spring and late summer (April, May, July, and August). The results also suggest that NPF was favoured on the weekends in comparison to workdays, likely due to the lower levels of condensation sinks in the mornings of weekends (CS weekdays 09:00: 18 × 10−3 s−1; CS weekend 09:00: 8 × 10−3 s−1). The median growth rates (GR) of ions during the NPF events varied between 3 and 7 nm h−1, increasing with the ion size and being higher on workdays than on weekends for intermediate and large ions. The median GR of small ions on the other hand were rather similar on workdays and weekends. In general, NPF bursts changed the diurnal cycle of particle number as well as intermediate and large ions by causing an extra peak between 09:00 and 14:00. On average, during the NPF bursts the concentrations of intermediate ions were 8.5–10 times higher than on NPF non-event days, depending on the polarity, and the concentrations of large ions and particles were 1.5–1.8 and 1.2 times higher, respectively. Because the median concentrations of intermediate ions were considerably higher on NPF event days in comparison to NPF non-event days, the results indicate that intermediate ion concentrations could be used as an indication for NPF in Paris. The results suggest that NPF was a source of ions and aerosol particles in Paris and therefore contributed to both air quality degradation and climatic effects, especially in the spring and summer.

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Impact of Urban Pollution on Organic-Mediated New-Particle Formation and Particle Number Concentration in the Amazon Rainforest

Environmental Science & Technology ◽

10.1021/acs.est.0c07465 ◽

2021 ◽

Vol 55 (8) ◽

pp. 4357-4367

Author(s):

Bin Zhao ◽

Jerome D. Fast ◽

Neil M. Donahue ◽

Manish Shrivastava ◽

Meredith Schervish ◽

...

Keyword(s):

Particle Number ◽

Urban Pollution ◽

Particle Formation ◽

Number Concentration ◽

Amazon Rainforest ◽

Particle Number Concentration ◽

New Particle Formation

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

Atmospheric Environment ◽

10.1016/j.atmosenv.2014.11.069 ◽

2015 ◽

Vol 103 ◽

pp. 7-17 ◽

Cited By ~ 27

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

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Modeling particle nucleation and growth over northern California during the 2010 CARES campaign

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-12283-2015 ◽

2015 ◽

Vol 15 (21) ◽

pp. 12283-12313 ◽

Cited By ~ 11

Author(s):

A. Lupascu ◽

R. Easter ◽

R. Zaveri ◽

M. Shrivastava ◽

M. Pekour ◽

...

Keyword(s):

Size Distribution ◽

Particle Number ◽

Particle Formation ◽

Number Concentration ◽

Aerosol Size Distribution ◽

Particle Nucleation ◽

Particle Number Concentration ◽

New Particle Formation ◽

Organic Vapors ◽

Diurnal Variability

Abstract. Accurate representation of the aerosol lifecycle requires adequate modeling of the particle number concentration and size distribution in addition to their mass, which is often the focus of aerosol modeling studies. This paper compares particle number concentrations and size distributions as predicted by three empirical nucleation parameterizations in the Weather Research and Forecast coupled with chemistry (WRF-Chem) regional model using 20 discrete size bins ranging from 1 nm to 10 μm. Two of the parameterizations are based on H2SO4, while one is based on both H2SO4 and organic vapors. Budget diagnostic terms for transport, dry deposition, emissions, condensational growth, nucleation, and coagulation of aerosol particles have been added to the model and are used to analyze the differences in how the new particle formation parameterizations influence the evolving aerosol size distribution. The simulations are evaluated using measurements collected at surface sites and from a research aircraft during the Carbonaceous Aerosol and Radiative Effects Study (CARES) conducted in the vicinity of Sacramento, California. While all three parameterizations captured the temporal variation of the size distribution during observed nucleation events as well as the spatial variability in aerosol number, all overestimated by up to a factor of 2.5 the total particle number concentration for particle diameters greater than 10 nm. Using the budget diagnostic terms, we demonstrate that the combined H2SO4 and low-volatility organic vapor parameterization leads to a different diurnal variability of new particle formation and growth to larger sizes compared to the parameterizations based on only H2SO4. At the CARES urban ground site, peak nucleation rates are predicted to occur around 12:00 Pacific (local) standard time (PST) for the H2SO4 parameterizations, whereas the highest rates were predicted at 08:00 and 16:00 PST when low-volatility organic gases are included in the parameterization. This can be explained by higher anthropogenic emissions of organic vapors at these times as well as lower boundary-layer heights that reduce vertical mixing. The higher nucleation rates in the H2SO4-organic parameterization at these times were largely offset by losses due to coagulation. Despite the different budget terms for ultrafine particles, the 10–40 nm diameter particle number concentrations from all three parameterizations increased from 10:00 to 14:00 PST and then decreased later in the afternoon, consistent with changes in the observed size and number distribution. We found that newly formed particles could explain up to 20–30 % of predicted cloud condensation nuclei at 0.5 % supersaturation, depending on location and the specific nucleation parameterization. A sensitivity simulation using 12 discrete size bins ranging from 1 nm to 10 μm diameter gave a reasonable estimate of particle number and size distribution compared to the 20 size bin simulation, while reducing the associated computational cost by ~ 36 %.

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CCN production by new particle formation in the free troposphere

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-1529-2017 ◽

2017 ◽

Vol 17 (2) ◽

pp. 1529-1541 ◽

Cited By ~ 17

Author(s):

Clémence Rose ◽

Karine Sellegri ◽

Isabel Moreno ◽

Fernando Velarde ◽

Michel Ramonet ◽

...

Keyword(s):

Particle Number ◽

Particle Growth ◽

Particle Formation ◽

Number Concentration ◽

Particle Number Concentration ◽

Free Troposphere ◽

New Particle Formation ◽

Data Set ◽

Radiative Processes ◽

The Impact

Abstract. Global models predict that new particle formation (NPF) is, in some environments, responsible for a substantial fraction of the total atmospheric particle number concentration and subsequently contributes significantly to cloud condensation nuclei (CCN) concentrations. NPF events were frequently observed at the highest atmospheric observatory in the world, on Chacaltaya (5240 m a.s.l.), Bolivia. The present study focuses on the impact of NPF on CCN population. Neutral cluster and Air Ion Spectrometer and mobility particle size spectrometer measurements were simultaneously used to follow the growth of particles from cluster sizes down to ∼ 2 nm up to CCN threshold sizes set to 50, 80 and 100 nm. Using measurements performed between 1 January and 31 December 2012, we found that 61 % of the 94 analysed events showed a clear particle growth and significant enhancement of the CCN-relevant particle number concentration. We evaluated the contribution of NPF, relative to the transport and growth of pre-existing particles, to CCN size. The averaged production of 50 nm particles during those events was 5072, and 1481 cm−3 for 100 nm particles, with a larger contribution of NPF compared to transport, especially during the wet season. The data set was further segregated into boundary layer (BL) and free troposphere (FT) conditions at the site. The NPF frequency of occurrence was higher in the BL (48 %) compared to the FT (39 %). Particle condensational growth was more frequently observed for events initiated in the FT, but on average faster for those initiated in the BL, when the amount of condensable species was most probably larger. As a result, the potential to form new CCN was higher for events initiated in the BL (67 % against 53 % in the FT). In contrast, higher CCN number concentration increases were found when the NPF process initially occurred in the FT, under less polluted conditions. This work highlights the competition between particle growth and the removal of freshly nucleated particles by coagulation processes. The results support model predictions which suggest that NPF is an effective source of CCN in some environments, and thus may influence regional climate through cloud-related radiative processes.

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New Particle Formation and impact on CCN concentrations in the boundary layer and free troposphere at the high altitude station of Chacaltaya (5240 m a.s.l.), Bolivia

10.5194/acp-2016-696 ◽

2016 ◽

Author(s):

C. Rose ◽

K. Sellegri ◽

I. Moreno ◽

F. Velarde ◽

M. Ramonet ◽

...

Keyword(s):

Boundary Layer ◽

Particle Number ◽

Particle Growth ◽

Particle Formation ◽

Number Concentration ◽

Particle Number Concentration ◽

Free Troposphere ◽

New Particle Formation ◽

Radiative Processes ◽

The Impact

Abstract. Global models predict that new particle formation (NPF) is, in some environments, responsible for a substantial fraction of the total atmospheric particle number concentration and subsequently contribute significantly to cloud condensation nuclei (CCN) concentrations. NPF events were frequently observed at the highest atmospheric observatory in the world, Chacaltaya (5240 m a.s.l.), Bolivia. The present study focuses on the impact of NPF on CCN population. Neutral cluster and Air Ion Spectrometer and mobility particle size spectrometer measurements were simultaneously used to follow the growth of particles from cluster sizes down to ~ 2 nm up to CCN threshold sizes set to 50, 80 and 100 nm. Using measurements performed between January 1 and December 31 2012, we found that 61% of the 94 analysed events showed a clear particle growth and significant enhancement of the CCN-relevant particle number concentration. We evaluated the contribution of NPF events relative to the transport of pre-existing particles to the site. The averaged production of 50 nm particles during those events was 5072 cm−3, and 1481 cm−3 for 100 nm particles, with a larger contribution of NPF compared to transport, especially during the wet season. The data set was further segregated into boundary layer (BL) and free troposphere (FT) conditions at the site. The NPF frequency of occurrence was higher in the BL (48 %) compared to the FT (39 %). Particle condensational growth was more frequently observed for events initiated in the FT, but on average faster for those initiated in the BL, when the amount of condensable species was most probably larger. As a result, the potential to form new CCN was higher for events initiated in the BL (67 % against 56 % in the FT). In contrast, higher CCN number concentration increases were found when the NPF process initially occurred in the FT, under less polluted conditions. This work highlights the competition between particle growth and the removal of freshly nucleated particles by coagulation processes. The results support model predictions which suggest that NPF is an effective source of CCN in some environments, and thus may influence regional climate through cloud related radiative processes.

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Wintertime new particle formation and its contribution to cloud condensation nuclei in the Northeastern United States

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-2591-2020 ◽

2020 ◽

Vol 20 (4) ◽

pp. 2591-2601

Author(s):

Fangqun Yu ◽

Gan Luo ◽

Arshad Arjunan Nair ◽

James J. Schwab ◽

James P. Sherman ◽

...

Keyword(s):

United States ◽

Particle Number ◽

Hydrological Cycle ◽

Cloud Condensation Nuclei ◽

Particle Formation ◽

New Particle Formation ◽

Northeastern United States ◽

Condensation Nuclei ◽

Upper Troposphere ◽

Inorganic Species

Abstract. Atmospheric particles can act as cloud condensation nuclei (CCN) and modify cloud properties and precipitation and thus indirectly impact the hydrological cycle and climate. New particle formation (NPF or nucleation), frequently observed at locations around the globe, is an important source of ultrafine particles and CCN in the atmosphere. In this study, wintertime NPF over the Northeastern United States (NEUS) is simulated with WRF-Chem coupled with a size-resolved (sectional) advanced particle microphysics (APM) model. Model-simulated variations in particle number concentrations during a 2-month period (November–December 2013) are in agreement with corresponding measurements taken at Pinnacle State Park (PSP), New York, and Appalachian State University (APP), North Carolina. We show that, even during wintertime, regional nucleation occurs and contributes significantly to ultrafine-particle and CCN number concentrations over the NEUS. The model shows that, due to low biogenic emissions during this period, wintertime regional nucleation is solely controlled by inorganic species and the newly developed ternary ion-mediated nucleation scheme is able to capture the variations in observed particle number concentrations (ranging from ∼200 to 20 000 cm−3) at both PSP and APP. Total particle and CCN number concentrations dramatically increase following NPF events and have the highest values over the Ohio Valley region, where elevated [SO2] is sustained by power plants. Secondary particles dominate particle number abundance over the NEUS, and their fraction increases with altitude from ≳85 % near the surface to ≳95 % in the upper troposphere. The secondary fraction of CCN also increases with altitude, from 20 %–50 % in the lower boundary layer to 50 %–60 % in the middle troposphere to 70 %–85 % in the upper troposphere.

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