Cluster analysis of atmospheric particle number size distributions at a rural site downwind of Seoul, Korea

Abstract. Atmospheric particle number size distributions of airborne particles (diameter range 10–500 nm) were measured over ten weeks at three sites in the vicinity of the A100 urban motorway in Berlin, Germany. The A100 carries about 180 000 vehicles on a weekday, and roadside particle size distributions showed a number maximum between 20 and 60 nm clearly related to the motorway emissions. The average total number concentration at roadside was 28 000 cm−3 with a total range between 1200 and 168 000 cm−3. At distances of 80 and 400 m from the motorway the concentrations decreased to mean levels of 11 000 and 9 000 cm−3, respectively. An obstacle-resolving dispersion model was applied to simulate the 3-D flow field and traffic tracer transport in the urban environment around the motorway. By inverse modelling, vehicle emission factors were derived, representative of a relative share of 6% lorry-like vehicles, and a driving speed of about 80 km h−1. Three different calculation approaches were compared, which differ in the choice of the experimental winds driving the flow simulation. The average emission factor per vehicle was 2.1(±0.2) · 1014 km−1 for particle number and 0.077(±0.01) · 1014 cm3 km−1 for particle volume. Regression analysis suggested that lorry-like vehicles emit 116 (± 21) times more particulate number than passenger car-like vehicles, and that lorry-like vehicles account for about 91% of particulate number emissions on weekdays. Our work highlights the increasing applicability of 3-D flow models in urban microscale environments and their usefulness in determining traffic emission factors.

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Particle formation at a continental background site: comparison of modelresults with observations

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-2-2413-2002 ◽

2002 ◽

Vol 2 (6) ◽

pp. 2413-2448

Author(s):

U. Uhrner ◽

W. Birmili ◽

F. Stratmann ◽

M. Wilck ◽

I. J. Ackermann ◽

...

Keyword(s):

Particle Size ◽

Sulphuric Acid ◽

Particle Number ◽

Particle Formation ◽

Rural Site ◽

Size Distributions ◽

Correction Factors ◽

Convective Conditions ◽

Particle Size Distributions ◽

Measured Particle

Abstract. At Hohenpeissenberg (47°48'N, 11°07'E, 988 m asl), a rural site 200-300 m higher than the surrounding terrain, sulphuric acid concentrations, particle size distributions, and other trace gas concentrations were measured over a two and a half year period. Measured particle number concentrations and inferred particle surface area-concentrations were compared with box-model simulations based on a multimodal lognormal aerosol module that included a binary sulphuric acid water nucleation scheme. The calculated nucleation rates were corrected with a factor to match measured particle number concentrations. These corrections varied over a range of 10-3 - 1017. The correction factors were close to 1 for the measurements made in the winter, which represented stable thermal stratification and low wind conditions. In contrast, the correction factors were the largest for measurements made under strong convective conditions. Our comparison of measured and simulated particle size distributions suggest a distant particle-formation process under convective conditions near the interface of the mixed layer and the entrainment zone, followed by downward transport and particle growth. For stable stratification and low winds, our comparisons suggest that particles formed close to the measurement site.

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Cluster analysis of submicron particle number size distributions at the SORPES station in the Yangtze River Delta of East China

Journal of Geophysical Research Atmospheres ◽

10.1029/2020jd034004 ◽

2021 ◽

Author(s):

Liangduo Chen ◽

Ximeng Qi ◽

Wei Nie ◽

Jiaping Wang ◽

Zheng Xu ◽

...

Keyword(s):

Cluster Analysis ◽

Yangtze River ◽

Particle Number ◽

Yangtze River Delta ◽

River Delta ◽

East China ◽

Size Distributions ◽

The Yangtze River ◽

Submicron Particle ◽

The Yangtze River Delta

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Temporal and spatial variability of atmospheric particle number size distributions across Spain

Atmospheric Environment ◽

10.1016/j.atmosenv.2018.06.046 ◽

2018 ◽

Vol 190 ◽

pp. 146-160 ◽

Cited By ~ 9

Author(s):

E. Alonso-Blanco ◽

F.J. Gómez-Moreno ◽

B. Artíñano ◽

S. Iglesias-Samitier ◽

V. Juncal-Bello ◽

...

Keyword(s):

Spatial Variability ◽

Particle Number ◽

Size Distributions ◽

Atmospheric Particle ◽

Temporal And Spatial Variability ◽

Temporal And Spatial

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Particle formation at a continental background site: comparison of model results with observations

Atmospheric Chemistry and Physics ◽

10.5194/acp-3-347-2003 ◽

2003 ◽

Vol 3 (2) ◽

pp. 347-359 ◽

Cited By ~ 7

Author(s):

U. Uhrner ◽

W. Birmili ◽

F. Stratmann ◽

M. Wilck ◽

I. J. Ackermann ◽

...

Keyword(s):

Particle Size ◽

Sulphuric Acid ◽

Particle Number ◽

Particle Formation ◽

Box Model ◽

Rural Site ◽

Data Sets ◽

Size Distributions ◽

Correction Factors ◽

Particle Size Distributions

Abstract. At Hohenpeissenberg (47° 48' N, 11° 07' E, 988 m asl), a rural site 200--300~m higher than the surrounding terrain, sulphuric acid concentrations, particle size distributions, and other trace gas concentrations were measured over a two and a half year period. Measured particle number concentrations and inferred particle surface area concentrations were compared with box-model simulations for 12 carefully selected data sets collected during the HAFEX experiment (Birmili et al., 2003). The 12 cases were selected after meteorological and aerosol dynamical criteria in order to justify the use of a box-model. The aerosol model included a binary sulphuric acid water nucleation scheme. Calculated nucleation rates were corrected with a factor to match measured and calculated particle number concentrations. For the investigated 12 data sets, the correction factors were smallest for measurements made under stable thermal stratification and low wind conditions, i.e. conditions that are frequently encountered during winter. Correction factors were largest for measurements made under strong convective conditions. Our comparison of measured and simulated particle size distributions suggests that the particle formation process maybe strongly influenced by mixing processes driven by thermal convection and/or wind sheer.

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Impact of the Coronavirus Pandemic Lockdown on Atmospheric Nanoparticle Concentrations in Two Sites of Southern Italy

Atmosphere ◽

10.3390/atmos12030352 ◽

2021 ◽

Vol 12 (3) ◽

pp. 352

Author(s):

Adelaide Dinoi ◽

Daniel Gulli ◽

Ivano Ammoscato ◽

Claudia R. Calidonna ◽

Daniele Contini

Keyword(s):

Particle Number ◽

Southern Italy ◽

Time Intervals ◽

Atmospheric Particle ◽

Total Particle Number ◽

Total Particle ◽

Consequent Reduction ◽

Containment Measures ◽

Coronavirus Infection ◽

The Impact

During the new coronavirus infection outbreak, the application of strict containment measures entailed a decrease in most human activities, with the consequent reduction of anthropogenic emissions into the atmosphere. In this study, the impact of lockdown on atmospheric particle number concentrations and size distributions is investigated in two different sites of Southern Italy: Lecce and Lamezia Terme, regional stations of the GAW/ACTRIS networks. The effects of restrictions are quantified by comparing submicron particle concentrations, in the size range from 10 nm to 800 nm, measured during the lockdown period and in the same period of previous years, from 2015 to 2019, considering three time intervals: prelockdown, lockdown and postlockdown. Different percentage reductions in total particle number concentrations are observed, −19% and −23% in Lecce and −7% and −4% in Lamezia Terme during lockdown and postlockdown, respectively, with several variations in each subclass of particles. From the comparison, no significant variations of meteorological factors are observed except a reduction of rainfall in 2020, which might explain the higher levels of particle concentrations measured during prelockdown at both stations. In general, the results demonstrate an improvement of air quality, more conspicuous in Lecce than in Lamezia Terme, during the lockdown, with a differed reduction in the concentration of submicronic particles that depends on the different types of sources, their distance from observational sites and local meteorology.

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A Cluster-Based Method for Improving Analysis of Polydisperse Particle Size Distributions Obtained by Nanoparticle Tracking

Journal of Nanoparticles ◽

10.1155/2013/936150 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 5

Author(s):

Thorsten Wagner ◽

Martin Wiemann ◽

Inge Schmitz ◽

Hans-Gerd Lipinski

Keyword(s):

Cluster Analysis ◽

Particle Size ◽

Particle Dispersion ◽

Optical Tracking ◽

Size Distributions ◽

Particle Size Distributions ◽

Mathematical Methods ◽

Polydisperse Suspension ◽

Polydisperse Particle ◽

Modal Values

Optical tracking methods are increasingly employed to characterize the size of nanoparticles in suspensions. However, the sufficient separation of different particle populations in polydisperse suspension is still difficult. In this work, Nanosight measurements of well-defined particle populations and Monte-Carlo simulations showed that the analysis of polydisperse particle dispersion could be improved with mathematical methods. Logarithmic transform of measured hydrodynamic diameters led to improved comparability between different modal values of multimodal size distributions. Furthermore, an automatic cluster analysis of transformed particle diameters could uncover otherwise hidden particle populations. In summary, the combination of logarithmically transformed hydrodynamic particle diameters with cluster analysis markedly improved the interpretability of multimodal particle size distributions as delivered by particle tracking measurements.

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Continental anthropogenic primary particle number emissions

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-6823-2016 ◽

2016 ◽

Vol 16 (11) ◽

pp. 6823-6840 ◽

Cited By ~ 32

Author(s):

Pauli Paasonen ◽

Kaarle Kupiainen ◽

Zbigniew Klimont ◽

Antoon Visschedijk ◽

Hugo A. C. Denier van der Gon ◽

...

Keyword(s):

Particle Number ◽

Road Traffic ◽

Agricultural Waste ◽

Coke Production ◽

Strong Increase ◽

Size Distributions ◽

Adverse Health Effects ◽

Carbon Particles ◽

First Results ◽

Aerosol Cloud Interactions

Abstract. Atmospheric aerosol particle number concentrations impact our climate and health in ways different from those of aerosol mass concentrations. However, the global, current and future anthropogenic particle number emissions and their size distributions are so far poorly known. In this article, we present the implementation of particle number emission factors and the related size distributions in the GAINS (Greenhouse Gas–Air Pollution Interactions and Synergies) model. This implementation allows for global estimates of particle number emissions under different future scenarios, consistent with emissions of other pollutants and greenhouse gases. In addition to determining the general particulate number emissions, we also describe a method to estimate the number size distributions of the emitted black carbon particles. The first results show that the sources dominating the particle number emissions are different to those dominating the mass emissions. The major global number source is road traffic, followed by residential combustion of biofuels and coal (especially in China, India and Africa), coke production (Russia and China), and industrial combustion and processes. The size distributions of emitted particles differ across the world, depending on the main sources: in regions dominated by traffic and industry, the number size distribution of emissions peaks in diameters range from 20 to 50 nm, whereas in regions with intensive biofuel combustion and/or agricultural waste burning, the emissions of particles with diameters around 100 nm are dominant. In the baseline (current legislation) scenario, the particle number emissions in Europe, Northern and Southern Americas, Australia, and China decrease until 2030, whereas especially for India, a strong increase is estimated. The results of this study provide input for modelling of the future changes in aerosol–cloud interactions as well as particle number related adverse health effects, e.g. in response to tightening emission regulations. However, there are significant uncertainties in these current emission estimates and the key actions for decreasing the uncertainties are pointed out.

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