scholarly journals Consequences of dynamic and timing properties of new aerosol particle formation and consecutive growth events

2018 ◽  
Author(s):  
Imre Salma ◽  
Zoltán Németh
Keyword(s):  
Dynamic Properties ◽  
Meteorological Data ◽  
Particle Diameter ◽  
Chemical Species ◽  
Particle Growth ◽  
Particle Formation ◽  
City Centre ◽  
Timing Properties ◽  
The City ◽  
Event Occurrence

Abstract. Dynamic properties, i.e. particle formation rate J6 and particle diameter growth rate GR10, and timing properties, i.e. starting time (t1) and duration time interval (Δt) of 247 quantifiable (class 1A) atmospheric new particle formation (NPF) and consecutive particle diameter growth events identified in the city centre and near-city background of Budapest over 6 full measurement years together with related gas-phase H2SO4 proxy, condensation sink (CS) of vapours, basic meteorological data and concentrations of criteria pollutant gases were derived, evaluated, discussed and interpreted. In the city centre, nucleation ordinarily starts at 09:15 UTC+1, and it is maintained for approximately 3 h. The NPF and growth events produce 4.6 aerosol particles with a diameter of 6 nm in 1 cm3 of air in 1 s, and cause the particles with a diameter of 10 nm to grow with a typical rate of 7.3 nm h−1. Nucleation starts approximately 1 h earlier in the near-city background, it shows substantially smaller J6 (with a median of 2.0 cm−3 s−1) and GR10 values (with a median of 5.0 nm h−1), while the duration of nucleation is similar to that in the centre. Monthly distributions of the dynamic properties and daily maximum H2SO4 proxy do not follow the mean monthly pattern of the event occurrence frequency. The factors that control the event occurrence and that govern the intensity of particle formation and growth are not directly linked. Condensing atmospheric chemical species and/or their processes in the city centre seem to contribute equally to new particle formation and particle growth. In the near-city background, however, chemical compounds available and their processes power particle growth more than particle formation. There is a minimum growth rate of approximately 1.8 nm h−1 that is required for nucleated particles to reach the lower end of the diameter interval measured (6 nm) under the actual/local conditions. Monthly distributions and relationships among the properties mentioned provided several indirect evidence that chemical species other than H2SO4 largely influence the particle growth and possibly atmospheric NPF process as well. The J6, GR10 and Δt can be described by log-normal distribution. Most of the extreme dynamic properties could not be explained by H2SO4 proxy, CS, meteorological data or pollutant gas concentrations. Approximately 40 % of the NPF and growth events exhibited broad beginning, which can be an urban feature. For 9 % of all cases, it was feasible to calculate 2 separate sets of dynamic properties. The later onset frequently shows more intensive particle formation and growth than the first onset by a typical factor of approximately 1.4. The first event is of regional type, while the second event, superimposed on the first, is often associated with sub-regional, thus urban NPF and growth process.

scholarly journals Dynamic and timing properties of new aerosol particle formation and consecutive growth events

2019 ◽  
Vol 19 (9) ◽  
pp. 5835-5852 ◽  
Author(s):  
Imre Salma ◽  
Zoltán Németh
Keyword(s):  
Aerosol Particle ◽  
Dynamic Properties ◽  
Particle Formation ◽  
City Centre ◽  
Time Interval ◽  
Growth Processes ◽  
Timing Properties ◽  
The City ◽  
Particle Formation And Growth ◽  
Event Occurrence

Abstract. Dynamic properties, i.e. particle formation rate J6 and particle diameter growth rate GR10, and timing properties, i.e. starting time (t1) and duration time interval (Δt) of 247 quantifiable atmospheric new aerosol particle formation (NPF) and growth events identified in the city centre and near-city background of Budapest over 6 full measurement years, together with related gas-phase H2SO4 proxy, condensation sink (CS) of vapours, basic meteorological data and concentrations of criteria pollutant gases were derived, evaluated, discussed and interpreted. In the city centre, nucleation ordinarily starts at 09:15 UTC + 1, and it is maintained for approximately 3 h. The NPF and growth events produce 4.6 aerosol particles with a diameter of 6 nm in 1 cm3 of air in 1 s and cause the particles with a diameter of 10 nm to grow at a typical rate of 7.3 nm h−1. Nucleation starts approximately 1 h earlier in the near-city background, and it shows substantially smaller J6 (with a median of 2.0 cm−3 s−1) and GR10 values (with a median of 5.0 nm h−1), while the duration of nucleation is similar to that in the centre. Monthly distributions of the dynamic properties and daily maximum H2SO4 proxy do not follow the mean monthly pattern of the event occurrence frequency. The factors that control the event occurrence and that govern the intensity of particle formation and growth are not directly linked. New particle formation and growth processes advance in a different manner in the city and its close environment. This could likely be related to diversities in atmospheric composition, chemistry and physics. Monthly distributions and relationships among the properties mentioned provided indirect evidence that chemical species other than H2SO4 largely influence the particle growth and possibly atmospheric NPF process as well. The J6, GR10 and Δt can be described by a log-normal distribution function. Most extreme dynamic properties could not be explained by available single or compound variables. Approximately 40 % of the NPF and growth events exhibited broad beginning, which can be an urban feature. For doublets, the later onset frequently shows more intensive particle formation and growth than the first onset by a typical factor of approximately 1.5. The first event is attributed to a regional type, while the second event, superimposed on the first, is often associated with subregional, thus urban NPF and growth processes.

scholarly journals Quantification of an atmospheric nucleation and growth process as a single source of aerosol particles in a city

2017 ◽  
Vol 17 (24) ◽  
pp. 15007-15017 ◽  
Author(s):  
Imre Salma ◽  
Veronika Varga ◽  
Zoltán Németh
Keyword(s):  
Growth Process ◽  
Particle Number ◽  
Urban Climate ◽  
Particle Diameter ◽  
City Centre ◽  
Time Interval ◽  
Single Source ◽  
Mean Values ◽  
Early Afternoon ◽  
The City

Abstract. Effects of a new aerosol particle formation (NPF) and particle diameter growth process as a single source of atmospheric particle number concentrations were evaluated and quantified on the basis of experimental data sets obtained from particle number size distribution measurements in the city centre and near-city background of Budapest for 5 years. Nucleation strength factors for a nucleation day (NSFNUC) and for a general day (NSFGEN) were derived separately for seasons and full years. The former characteristic represents the concentration increment of ultrafine (UF) particles specifically on nucleation days with respect to accumulation-mode (regional background) concentrations (particles with equivalent diameters of 100–1000 nm; N100−1000) due solely to the nucleation process. The latter factor expresses the contribution of nucleation to particle numbers on general days; thus, it represents a longer time interval such as season or year. The nucleation source had the largest effect on the concentrations around noon and early afternoon, as expected. During this time interval, it became the major source of particles in the near-city background. Nucleation increased the daily mean concentrations on nucleation days by mean factors of 2.3 and 1.58 in the near-city background and city centre, respectively. Its effect was largest in winter, which was explained by the substantially lower N100−1000 levels on nucleation days than those on non-nucleation days. On an annual timescale, 37 % of the UF particles were generated by nucleation in the near-city background, while NPF produced 13 % of UF particles in the city centre. The differences among the annual mean values, and among the corresponding seasonal mean values, were likely caused by the variability in controlling factors from year to year. The values obtained represent the lower limits of the contributions. The shares determined imply that NPF is a non-negligible or substantial source of particles in near-city background environments and even in city centres, where the vehicular road emissions usually prevail. Atmospheric residence time of nucleation-mode particles was assessed by a decay curve analysis, and a mean of 02:30 was obtained. The present study suggests that the health-related consequences of the atmospheric NPF and growth process in cities should also be considered in addition to its urban climate implications.

scholarly journals Spatial extension of nucleating air masses in the Carpathian Basin

2014 ◽  
Vol 14 (16) ◽  
pp. 8841-8848 ◽  
Author(s):  
Z. Németh ◽  
I. Salma
Keyword(s):  
Particle Growth ◽  
Middle Part ◽  
Carpathian Basin ◽  
City Centre ◽  
Southeastern Part ◽  
Air Masses ◽  
Contour Plots ◽  
Time Parameters ◽  
Particle Sizer ◽  
The City

Abstract. Particle number size distributions were measured by differential mobility particle sizer in the diameter range of 6–1000 nm in the near-city background and city centre of Budapest continuously for two years. The city is situated in the middle part of the Carpathian Basin, which is a topographically discrete unit in the southeastern part of central Europe. Yearly mean nucleation frequencies and uncertainties for the near-city background and city centre were (28 + 6/−4) % and (27 + 9/−4) %, respectively. The total numbers of days with continuous and uninterrupted growth process were 43 and 31, respectively. These events and their properties were utilised to investigate the spatial scale of the nucleation in the basin, and whether there are any specific trajectories for the nucleating air masses. Local wind speed and direction data indicated that there seem to be differences between the nucleation and growth intervals and non-nucleation days. For further analysis, backward trajectories were generated by a simple air parcel trajectory model. Start and end time parameters of the nucleation and an end time parameter of the particle growth were derived by a standardised procedure based on examining the channel contents of the contour plots. These parameters were used to specify a segment on each backward trajectory that is associated with the nucleating air mass. The results indicated that regional nucleation happened in the continental boundary layer mostly in the Carpathian Basin but that the most distant trajectories originated outside of the basin. The nucleating air masses were predominantly associated with NW and SE geographical sectors, and some of them were also related to larger forested territories. The results also emphasised indirectly that the regional new particle formation and growth phenomena observable at the fixed location often expand to the bulk of the Carpathian Basin.

scholarly journals Particle hygroscopicity during atmospheric new particle formation events: implications for the chemical species contributing to particle growth

2013 ◽  
Vol 13 (13) ◽  
pp. 6637-6646 ◽  
Author(s):  
Z. Wu ◽  
W. Birmili ◽  
L. Poulain ◽  
Z. Wang ◽  
M. Merkel ◽  
...  
Keyword(s):  
Growth Rate ◽  
Sulfuric Acid ◽  
Chemical Species ◽  
Particle Growth ◽  
Particle Formation ◽  
Water Soluble ◽  
Alternative Methods ◽  
Normal Distribution Function ◽  
Particle Fraction ◽  
New Particle Formation

Abstract. This study examines the hygroscopicity of newly formed particles (diameters range 25–45 nm) during two atmospheric new particle formation (NPF) events in the German mid-level mountains during the Hill Cap Cloud Thuringia 2010 (HCCT-2010) field experiment. At the end of the NPF event involving clear particle growth, we measured an unusually high soluble particle fraction of 58.5% at 45 nm particle size. The particle growth rate contributed through sulfuric acid condensation only accounts for around 6.5% of the observed growth rate. Estimations showed that sulfuric acid condensation explained, however, only around 10% of that soluble particle fraction. Therefore, the formation of additional water-soluble matter appears imperative to explain the missing soluble fraction. Although direct evidence is missing, we consider water-soluble organics as candidates for this mechanism. For the case with clear growth process, the particle growth rate was determined by two alternative methods based on tracking the mode diameter of the nucleation mode. The mean particle growth rate obtained from the inter-site data comparison using Lagrangian consideration is 3.8 (± 2.6) nm h−1. During the same period, the growth rate calculated based on one site data is 5.0 nm h−1 using log-normal distribution function method. In light of the fact that considerable uncertainties could be involved in both methods, we consider both estimated growth rates consistent.

scholarly journals Quantification of atmospheric nucleation and growth process as a single source of aerosol particles in a city

2017 ◽  
Author(s):  
Imre Salma ◽  
Veronika Varga ◽  
Zoltán Németh
Keyword(s):  
Growth Process ◽  
Particle Number ◽  
Particle Diameter ◽  
City Centre ◽  
Background Concentration ◽  
Time Interval ◽  
Single Source ◽  
Mean Values ◽  
Early Afternoon ◽  
The City

Abstract. Effects of new aerosol particle formation (NPF) and particle diameter growth process as a single source on atmospheric particle number concentrations were evaluated and quantified on the basis of experimental data sets obtained from particle number size distribution measurements in the city centre and near-city background of Budapest for 5 years. Nucleation strength factors separately for nucleation days (NSFnucl days) and for all days (NSFall days) were derived for seasons and full years. The former characteristics represents the concentration increment of ultrafine (UF) particle numbers with respect to background concentration due solely to nucleation specifically on nucleation days. The latter factor expresses the contribution of nucleation process to the background particle number concentrations in general, thus on a longer time interval such as season or year. The nucleation source had the largest effect on particle concentrations around noon and early afternoon as expected. During this time interval, it became the major source of particles in the near-city background. Nucleation increased the daily mean particle number concentrations on nucleation days by mean factors of 2.3 and 1.58 in the near-city background and city centre, respectively. Its effect was the largest in winter, which was explained with the substantially lower background concentration levels on nucleation days than that on non-nucleation days. On an annual time scale, 37 % of the UF particles were generated by nucleation in the near-city background, while NPF produced 13 % of UF particles in the city centre. The differences among the annual mean values, and among the corresponding seasonal mean values were likely caused by the variability in controlling factors from year to year. The values obtained represent lower limits of contributions. The shares determined imply that NPF is a non-negligible or substantial source of particles in near-city background environments and even in city centres, where the vehicular road emissions usually prevail. Atmospheric residence time of nucleation-mode particles was assessed by decay curve analysis of N6–25 concentrations in time, and a mean of 2:30 was obtained. The present study suggests that the health-related consequences of atmospheric NPF and growth process in cities should also be considered in addition to its urban climate implications.

scholarly journals Particle hygroscopicity during atmospheric new particle formation events: implications for the chemical species contributing to particle growth

2012 ◽  
Vol 12 (5) ◽  
pp. 11415-11443
Author(s):  
Z. Wu ◽  
W. Birmili ◽  
L. Poulain ◽  
M. Merkel ◽  
B. Fahlbusch ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Soluble Fraction ◽  
Chemical Species ◽  
Particle Growth ◽  
Particle Formation ◽  
Water Soluble ◽  
Mountain Range ◽  
New Particle Formation ◽  
Particle Mobility ◽  
Significant Difference

Abstract. This study examines the hygroscopicity of newly formed particles (smaller than 50 nm in particle mobility diameter) during two atmospheric new particle formation events with and without clear growth process at mid-level mountain range in Central Germany based on HCCT field campaign. Particle hygroscopicity measurements show that the particle soluble fractions at the end of event for two events are, respectively 60% (45 nm particles for the event with clear growth) and 20% (30 nm particles for the event without clear growth), stressing that non-soluble organic compounds may play a key role in particle growth during new particle formation event. Such significant difference in particle hygroscopicity also suggests that the chemical species responsible for nucleation particle growth are considerably different between the two selected NPF events. During both events, the hygroscopicity of newly formed particles decreased with particle growth, indicating that more less-hygroscopic compounds contribute to the subsequent condensation in contrast to the earlier stage. Sulfuric acid was considered to be responsible of the NPF event and represent the highly hygroscopic compounds. However, calculation demonstrated that sulfuric acid condensation failed to fully explain the observed soluble fraction in the nucleation mode particles. Therefore, we hypothesize that some water-soluble matters may explain the missing soluble fraction.

scholarly journals Natural new particle formation at the coastal Antarctic site Neumayer

2015 ◽  
Vol 15 (11) ◽  
pp. 15655-15681
Author(s):  
R. Weller ◽  
K. Schmidt ◽  
K. Teinilä ◽  
R. Hillamo
Keyword(s):  
Growth Rates ◽  
Cloud Condensation Nuclei ◽  
Particle Diameter ◽  
Particle Growth ◽  
Particle Formation ◽  
New Particle Formation ◽  
Particle Size Distributions ◽  
Polar Night ◽  
Volatile Precursor ◽  
Simple Estimation

Abstract. We measured condensation particle (CP) concentrations and particle size distributions at the coastal Antarctic station Neumayer (70°39' S, 8°15' W) during two summer campaigns (from 20 January to 26 March 2012 and 1 February to 30 April 2014) and during polar night between 12 August and 27 September 2014 in the particle diameter (Dp) range from 2.94 to 60.4 nm (2012) and from 6.26 to 212.9 nm (2014). During both summer campaigns we identified all in all 44 new particle formation (NPF) events. From 10 NPF events, particle growth rates could be determined to be around 0.90 ± 0.46 nm h−1 (mean ± SD; range: 0.4 to 1.9 nm h−1). With the exception of one case, particle growth was generally restricted to the nucleation mode (Dp < 25 nm) and the duration of NPF events was typically around 6.0 ± 1.5 h (mean ± SD; range: 4 to 9 h). Thus in the main, particles did not grow up to sizes required for acting as cloud condensation nuclei. NPF during summer usually occurred in the afternoon in coherence with local photochemistry. During winter, two NPF events could be detected, though showing no ascertainable particle growth. A simple estimation indicated that apart from sulfuric acid, the derived growth rates required other low volatile precursor vapours.

scholarly journals Aerosols and nucleation in eastern China: first insights from the new SORPES-NJU station

2014 ◽  
Vol 14 (4) ◽  
pp. 2169-2183 ◽  
Author(s):  
E. Herrmann ◽  
A. J. Ding ◽  
V.-M. Kerminen ◽  
T. Petäjä ◽  
X. Q. Yang ◽  
...  
Keyword(s):  
Meteorological Data ◽  
Cloud Condensation Nuclei ◽  
Eastern China ◽  
Formation Rate ◽  
Particle Growth ◽  
Particle Formation ◽  
Accurate Estimate ◽  
New Particle Formation ◽  
The Mean ◽  
Measurement Period

Abstract. Aerosols and new particle formation were studied in the western part of the Yangtze River Delta (YRD) at the Station for Observing Regional Processes of the Earth System, Nanjing University (SORPES-NJU). Air ions in the diameter range 0.8–42 nm were measured using an air ion spectrometer, and a differential mobility particle sizer (DMPS) provided particle number size distributions between 6 and 800 nm. Additionally, meteorological data, trace gas concentrations, and PM2.5 values were recorded. During the measurement period from 18 November 2011 to 31 March 2012, the mean total particle concentration was found to be 23 000 cm−3 and the mean PM2.5 value was 90 μg m−3, well above national limits. We observed 26 new particle formation events occurred during the measurement period, producing 6 nm particles at a rate of about 1 cm−3 s−1. Typical particle growth rates were between 6 and 7 nm h−1. On average, new particle formation and growth were estimated to enhance cloud condensation nuclei concentration by about a factor of two during these event days. Ion measurements showed the typical cluster band below 2 nm, with total ion concentrations between about 600 and 1000 cm−3. A peculiar feature of the ion measurements were heightened ion cluster concentrations during the nights before the event days. At 2 nm, the formation rate of charged particles was only about 0.2% of the total rate, pointing towards an only marginal role of ion-induced nucleation. Based on observations, a simple empirical criterion was deducted to estimate particle formation probability. Dominated by radiation and relative humidity, the criterion can predict the occurrence of particle formation with a 90% accuracy. In a similar fashion, a reasonably accurate estimate of particle formation rates was derived. Combined, these parameters allow for a description of particle formation based on a few basic measured variables.

scholarly journals Natural new particle formation at the coastal Antarctic site Neumayer

2015 ◽  
Vol 15 (19) ◽  
pp. 11399-11410 ◽  
Author(s):  
R. Weller ◽  
K. Schmidt ◽  
K. Teinilä ◽  
R. Hillamo
Keyword(s):  
Growth Rates ◽  
Cloud Condensation Nuclei ◽  
Particle Diameter ◽  
Particle Growth ◽  
Particle Formation ◽  
New Particle Formation ◽  
Particle Size Distributions ◽  
Polar Night ◽  
Volatile Precursor ◽  
Simple Estimation

Abstract. We measured condensation particle (CP) concentrations and particle size distributions at the coastal Antarctic station Neumayer (70°39´ S, 8°15´ W) during two summer campaigns (from 20 January to 26 March 2012 and 1 February to 30 April 2014) and during the polar night between 12 August and 27 September 2014 in the particle diameter (Dp) range from 2.94 to 60.4 nm (2012) and from 6.26 to 212.9 nm (2014). During both summer campaigns we identified all in all 44 new particle formation (NPF) events. From 10 NPF events, particle growth rates could be determined to be around 0.90 ± 0.46 nm h−1 (mean ± SD; range: 0.4–1.9 nm h−1). With the exception of one case, particle growth was generally restricted to the nucleation mode (Dp < 25 nm) and the duration of NPF events was typically around 6.0 ± 1.5 h (mean ± SD; range: 4–9 h). Thus, in the surrounding area of Neumayer, particles did not grow up to sizes required for acting as cloud condensation nuclei. NPF during summer usually occurred in the afternoon in coherence with local photochemistry. During winter, two NPF events could be detected, though showing no ascertainable particle growth. A simple estimation indicated that apart from sulfuric acid, the derived growth rates required other low volatile precursor vapours.

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