Submicron aerosols at thirteen diversified sites in China: size distribution, new particle formation and corresponding contribution to cloud condensation nuclei production

Abstract. Understanding the particle number size distributions in diversified atmospheric environments is important in order to design mitigation strategies related to submicron particles and their effects on regional air quality, haze and human health. In this study, we conducted 15 different field measurement campaigns between 2007 and 2011 at 13 individual sites in China, including five urban sites, four regional sites, three coastal/background sites and one ship cruise measurement along eastern coastline of China. Size resolved particles were measured in the 15–600 nm size range. The median particle number concentrations (PNCs) were found to vary in the range of 1.1−2.2 × 104 cm−3 at urban sites, 0.8−1.5 × 104 cm−3 at regional sites, 0.4−0.6 × 104 cm−3 at coastal/background sites, and 0.5 × 104 cm−3 during cruise measurement. Peak diameters at each of these sites varied greatly from 24 to 115 nm. Particles in the 15–25 nm (nucleation mode), 25–100 nm (Aitken mode) and 100–600 nm (accumulation mode) range showed different characteristics at each sites, indicating the features of primary emissions and secondary formation in these diversified atmospheric environments. Diurnal variations show a build-up of accumulation mode particles belt at regional sites, suggesting the contribution of regional secondary aerosol pollution. Frequencies of new particle formation (NPF) events were much higher at urban and regional sites than at coastal sites and during cruise measurement. The average growth rates (GRs) of nucleation mode particles were 8.0–10.9 nm h−1 at urban sites, 7.4–13.6 nm h−1 at regional sites and 2.8–7.5 nm h−1 at coastal sites and during cruise measurement. The high gaseous precursors and strong oxidation at urban and regional sites not only favored the formation of particles, but also accelerated the growth rate of the nucleation mode particles. No significant difference in condensation sink (CS) during NPF days were observed among different site types, suggesting that the NPF events in background areas were more influenced by the pollutant transport. In addition, average contributions of NPF events to potential cloud condensation nuclei (CCN) at 0.2% super-saturation in the afternoon of all sampling days were calculated as 11% and 6% at urban sites and regional sites, respectively. On the other hand, NPF events at coastal sites and during cruise measurement had little impact on potential production of CCN. This study provides a large data set of particle size distribution in diversified atmosphere of China, improving our general understanding of emission, secondary formation, new particle formation and corresponding CCN activity of submicron aerosols in Chinese environments.

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Submicron aerosols at thirteen diversified sites in China: size distribution, new particle formation and corresponding contribution to cloud condensation nuclei production

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-14-15149-2014 ◽

2014 ◽

Vol 14 (10) ◽

pp. 15149-15189 ◽

Cited By ~ 2

Author(s):

J. F. Peng ◽

M. Hu ◽

Z. B. Wang ◽

X. F. Huang ◽

P. Kumar ◽

...

Keyword(s):

Size Distribution ◽

Particle Number ◽

Cloud Condensation Nuclei ◽

Particle Formation ◽

New Particle Formation ◽

Condensation Nuclei ◽

Accumulation Mode ◽

Nucleation Mode ◽

Secondary Formation ◽

Urban Sites

Abstract. Understanding the particle number size distributions in diversified atmospheric environments is important in order to design mitigation strategies related to submicron particles and their effect on regional air quality, haze and human health. In this study, we conducted 15 different field measurement campaigns, each one-month long, between 2007 and 2011 at 13 individual sites in China. These were 5 urban sites, 4 regional sites, 3 coastal/background sites and one ship cruise measurement along eastern coastline of China. Size resolved particles were measured in the 15–600 nm size range. The median particle number concentrations (PNC) were found to vary in the range of 1.1–2.2 × 104 cm−3 at urban sites, 0.8–1.5 × 104 cm−3 at regional sites, 0.4–0.6 × 104 cm−3 at coastal/background sites, and 0.5 × 104 cm−3 during cruise measurements. Peak diameters at each of these sites varied greatly from 24 nm to 115 nm. Particles in the 15–25 nm (nucleation mode), 25–100 nm (Aitken mode) and 100–600 nm (accumulation mode) range showed different characteristics at each of the studied sites, indicating the features of primary emissions and secondary formation in these diversified atmospheric environments. Diurnal variations show a build-up of accumulation mode particles belt at regional sites, suggesting the contribution of regional secondary aerosol pollution. Frequencies of new particle formation (NPF) events were much higher at urban and regional sites than at coastal sites and cruise measurement. The average growth rates (GRs) of nucleation mode particles were 8.0–10.9 nm h−1 at urban sites, 7.4–13.6 nm h−1 at regional sites and 2.8–7.5 nm h−1 at both coastal and cruise measurement sites. The high gaseous precursors and strong oxidation at urban and regional sites not only favored the formation of particles, but also accelerated the growth rate of the nucleation mode particles. No significant difference in condensation sink (CS) during NPF days were observed among different site types, suggesting that the NPF events in background area were more influenced by the pollutant transport. In addition, average contributions of NPF events to potential cloud condensation nuclei (CCN) at 0.2% super-saturation in the afternoon of all sampling days were calculated as 11% and 6% at urban sites and regional sites, respectively. On the other hand, NPF events at coastal and cruise measurement sites had little impact on potential production of CCN. This study provides a large dataset of aerosol size distribution in diversified atmosphere of China, improving our general understanding of emission, secondary formation, new particles formation and corresponding CCN activity of submicron aerosols in Chinese environments.

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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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Variation of size-segregated particle number concentrations in wintertime Beijing

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-1201-2020 ◽

2020 ◽

Vol 20 (2) ◽

pp. 1201-1216 ◽

Cited By ~ 10

Author(s):

Ying Zhou ◽

Lubna Dada ◽

Yiliang Liu ◽

Yueyun Fu ◽

Juha Kangasluoma ◽

...

Keyword(s):

Particle Number ◽

Particle Formation ◽

Number Concentration ◽

Spatial And Temporal Variability ◽

Particle Number Concentration ◽

New Particle Formation ◽

Accumulation Mode ◽

Nucleation Mode ◽

Secondary Sources ◽

Haze Days

Abstract. The spatial and temporal variability of the number size distribution of aerosol particles is an indicator of the dynamic behavior of Beijing's atmospheric pollution cocktail. This variation reflects the strength of different primary and secondary sources, such as traffic and new particle formation, as well as the main processes affecting the particle population. In this paper, we report size-segregated particle number concentrations observed at a newly developed Beijing station during the winter of 2018. Our measurements covered particle number size distributions over the diameter range of 1.5 nm–1 µm (cluster mode, nucleation mode, Aitken mode and accumulation mode), thus being descriptive of a major fraction of the processes taking place in the atmosphere of Beijing. Here we focus on explaining the concentration variations in the observed particle modes, by relating them to the potential aerosol sources and sinks, and on understanding the connections between these modes. We considered haze days and new particle formation event days separately. Our results show that during the new particle formation (NPF) event days increases in cluster mode particle number concentration were observed, whereas during the haze days high concentrations of accumulation mode particles were present. There was a tight connection between the cluster mode and nucleation mode on both NPF event and haze days. In addition, we correlated the particle number concentrations in different modes with concentrations of trace gases and other parameters measured at our station. Our results show that the particle number concentration in all the modes correlated with NOx, which reflects the contribution of traffic to the whole submicron size range. We also estimated the contribution of ion-induced nucleation in Beijing, and we found this contribution to be negligible.

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New particle formation and its effect on cloud condensation nuclei abundance in the summer Arctic: a case study in the Fram Strait and Barents Sea

Atmospheric Chemistry and Physics ◽

10.5194/acp-19-14339-2019 ◽

2019 ◽

Vol 19 (22) ◽

pp. 14339-14364 ◽

Cited By ~ 3

Author(s):

Simonas Kecorius ◽

Teresa Vogl ◽

Pauli Paasonen ◽

Janne Lampilahti ◽

Daniel Rothenberg ◽

...

Keyword(s):

Cloud Condensation Nuclei ◽

Particle Diameter ◽

Negative Ions ◽

Particle Formation ◽

Number Concentration ◽

The Arctic ◽

New Particle Formation ◽

Condensation Nuclei ◽

Nucleation Mode ◽

Particle Formation And Growth

Abstract. In a warming Arctic the increased occurrence of new particle formation (NPF) is believed to originate from the declining ice coverage during summertime. Understanding the physico-chemical properties of newly formed particles, as well as mechanisms that control both particle formation and growth in this pristine environment, is important for interpreting aerosol–cloud interactions, to which the Arctic climate can be highly sensitive. In this investigation, we present the analysis of NPF and growth in the high summer Arctic. The measurements were made on-board research vessel Polarstern during the PS106 Arctic expedition. Four distinctive NPF and subsequent particle growth events were observed, during which particle (diameter in a range 10–50 nm) number concentrations increased from background values of approx. 40 up to 4000 cm−3. Based on particle formation and growth rates, as well as hygroscopicity of nucleation and the Aitken mode particles, we distinguished two different types of NPF events. First, some NPF events were favored by negative ions, resulting in more-hygroscopic nucleation mode particles and suggesting sulfuric acid as a precursor gas. Second, other NPF events resulted in less-hygroscopic particles, indicating the influence of organic vapors on particle formation and growth. To test the climatic relevance of NPF and its influence on the cloud condensation nuclei (CCN) budget in the Arctic, we applied a zero-dimensional, adiabatic cloud parcel model. At an updraft velocity of 0.1 m s−1, the particle number size distribution (PNSD) generated during nucleation processes resulted in an increase in the CCN number concentration by a factor of 2 to 5 compared to the background CCN concentrations. This result was confirmed by the directly measured CCN number concentrations. Although particles did not grow beyond 50 nm in diameter and the activated fraction of 15–50 nm particles was on average below 10 %, it could be shown that the sheer number of particles produced by the nucleation process is enough to significantly influence the background CCN number concentration. This implies that NPF can be an important source of CCN in the Arctic. However, more studies should be conducted in the future to understand mechanisms of NPF, sources of precursor gases and condensable vapors, as well as the role of the aged nucleation mode particles in Arctic cloud formation.

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Characteristics of Aerosol Size Distributions and New Particle Formation Events at Delhi: An Urban Location in the Indo-Gangetic Plains

Frontiers in Earth Science ◽

10.3389/feart.2021.750111 ◽

2021 ◽

Vol 9 ◽

Author(s):

Sandhya Jose ◽

Amit Kumar Mishra ◽

Neelesh K. Lodhi ◽

Sudhir Kumar Sharma ◽

Sachchidanand Singh

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

Aerosol Particle ◽

Particle Number ◽

Particle Formation ◽

Number Concentration ◽

New Particle Formation ◽

Nucleation Mode ◽

Aerosol Particle Size

Accurate information about aerosol particle size distribution and its variation under different meteorological conditions are essential for reducing uncertainties related to aerosol-cloud-climate interaction processes. New particle formation (NPF) and the coagulation significantly affect the aerosol size distribution. Here we study the monthly and seasonal variability of aerosol particle size distribution at Delhi from December 2011 to January 2013. Analysis of aerosol particle size distribution using WRAS-GRIMM reveals that aerosol particle number concentration is highest during the post monsoon season owing to the effect of transported crop residue and biomass burning aerosols. Diurnal variations in number concentration show a bimodal pattern with two Aitken mode peaks in all the seasons. Monthly volume size distribution also shows bi-modal distribution with distinct coarse and fine modes. NPF events are observed less frequently in Delhi. Out of 222 days of WRAS data, only 17 NPF events have been observed, with higher NPF frequency during summer season. Growth rate of the nucleation mode of NPF events vary in the range 1.88–21.66 nm/h with a mean value of ∼8.45 ± 5.73 nm/h. It is found that during NPF events the Aitken and nucleation mode particles contribute more to the number concentration. Simultaneous measurement of UV flux and particulate matter (PM10 and PM2.5) have also been done along with particle number size distribution measurement to understand the possible mechanisms for NPF events over the study location.

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Wintertime New Particle Formation and Its Contribution to Cloud Condensation Nuclei in the Northeastern United States

10.5194/acp-2019-936 ◽

2019 ◽

Author(s):

Fangqun Yu ◽

Gan Luo ◽

Arshad Nair ◽

James J. Schwab ◽

James P. Sherman ◽

...

Keyword(s):

United States ◽

Particle Number ◽

Cloud Condensation Nuclei ◽

Particle Formation ◽

New Particle Formation ◽

Northeastern United States ◽

Condensation Nuclei ◽

Near Surface ◽

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 of particle number concentrations during a two-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. 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 of observed particle number concentrations (ranging from ~ 200–20 000 cm−3) at both PSP and APP. Total particle and CCN number concentrations dramatically increase following NPF events and have 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 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. This significant contribution of wintertime nucleation to aerosols, especially those that can act as CCN, is important considering the changing paradigm of wintertime precipitation over the NEUS.

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Measurement report: The influence of traffic and new particle formation on the size distribution of 1–800 nm particles in Helsinki: a street canyon and an urban background station comparison

10.5194/acp-2020-1282 ◽

2021 ◽

Author(s):

Magdalena Okuljar ◽

Heino Kuuluvainen ◽

Jenni Kontkanen ◽

Olga Garmash ◽

Miska Olin ◽

...

Keyword(s):

Size Distribution ◽

Street Canyon ◽

Particle Number ◽

Particle Formation ◽

Urban Environments ◽

Accumulation Mode ◽

Nucleation Mode ◽

Local Sources ◽

Non Local ◽

Aitken Mode

Abstract. Most of the anthropogenic air pollution sources are located in urban environments. The contribution of these sources to the population of atmospheric particles in the urban environment is poorly known. In this study, we investigated the aerosol particle number concentrations in a diameter range from 1 to 800 nm at a street canyon site and at a background station within 1 km from each other in Helsinki, Finland. We use these number size distribution data together with complementary trace gas data and develop a method to estimate the relative contributions of traffic and atmospheric new particle formation (NPF) to the concentrations of sub 3 nm particles. During the daytime, the particle concentrations were higher at the street canyon site than at the background station in all analyzed modes: sub 3 nm particles, nucleation mode (3–25 nm), Aitken mode (25–100 nm), and accumulation mode (100–800 nm). The population of sub-3 nm and nucleation mode particles was linked to local sources such as traffic, while the accumulation mode particles were more related to non-local sources. Aitken mode particles were dominated by local sources at the street canyon site while at the background station they were mainly influenced by non-local sources. The results of this study support earlier research showing direct emissions of the sub 3 nm particles from traffic. However, by using our new method, we show that during NPF events, traffic contribution to the total sub-3 nm particle concentration can be small and during daytime (6:00–20:00) in spring it does not dominate the sub-3 nm particle population at either of the researched sites. In the future, this method can be applied to estimate the contribution of traffic to particle number concentrations in different urban environments. This knowledge is needed to evaluate the effects of traffic on urban air quality.

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Measurement report: The influence of traffic and new particle formation on the size distribution of 1–800 nm particles in Helsinki – a street canyon and an urban background station comparison

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-9931-2021 ◽

2021 ◽

Vol 21 (13) ◽

pp. 9931-9953

Author(s):

Magdalena Okuljar ◽

Heino Kuuluvainen ◽

Jenni Kontkanen ◽

Olga Garmash ◽

Miska Olin ◽

...

Keyword(s):

Size Distribution ◽

Street Canyon ◽

Particle Number ◽

Particle Formation ◽

Urban Environments ◽

Accumulation Mode ◽

Nucleation Mode ◽

Local Sources ◽

Non Local ◽

Aitken Mode

Abstract. Most of the anthropogenic air pollution sources are located in urban environments. The contribution of these sources to the population of atmospheric particles in the urban environment is poorly known. In this study, we investigated the aerosol particle number concentrations in a diameter range from 1 to 800 nm at a street canyon site and at a background station within 1 km from each other in Helsinki, Finland. We use these number size distribution data together with complementary trace gas data and develop a method to estimate the relative contributions of traffic and atmospheric new particle formation (NPF) to the concentrations of sub-3 nm particles. During the daytime, the particle concentrations were higher at the street canyon site than at the background station in all analyzed modes: sub-3 nm particles, nucleation mode (3–25 nm), Aitken mode (25–100 nm), and accumulation mode (100–800 nm). The population of sub-3 nm and nucleation mode particles was linked to local sources such as traffic, while the accumulation mode particles were more related to non-local sources. Aitken mode particles were dominated by local sources at the street canyon site, while at the background station they were mainly influenced by non-local sources. The results of this study support earlier research showing direct emissions of the sub-3 nm particles from traffic. However, by using our new method, we show that, during NPF events, traffic contribution to the total sub-3 nm particle concentration can be small and during daytime (6:00–20:00) in spring it does not dominate the sub-3 nm particle population at either of the researched sites. In the future, the contribution of traffic to particle number concentrations in different urban environments can be estimated with a similar approach, but determining the relationships between the gas and particle concentrations from observations needs to be conducted with longer data sets from different urban environments.

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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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