scholarly journals New particle formation at urban and high-altitude remote sites in the south-eastern Iberian Peninsula

Author(s):  
Juan Andrés Casquero-Vera ◽  
Hassan Lyamani ◽  
Lubna Dada ◽  
Simo Hakala ◽  
Pauli Paasonen ◽  
...  

Abstract. A substantial fraction of the atmospheric aerosols originates from secondary new particle formation (NPF), where atmospheric vapours are transformed into particles that subsequently grow to larger sizes, affecting human health and the climate. In this study, we investigate aerosol size distributions at two stations located close to each other (~ 20 km), but at different altitudes: urban (UGR; 680 m a.s.l.) and high-altitude remote (SNS; 2500 m a.s.l.) site, both in the area of Granada, Spain, and part of AGORA observatory (Andalusian Global ObseRvatory of the Atmosphere). The analysis shows a significant contribution of nucleation mode aerosol particles to the total aerosol number concentration at both sites, with a contribution of 47 % and 48 % at SNS and UGR, respectively. Due to the important contribution of NPF events to the total aerosol number concentrations and their high occurrence frequency (> 70 %) during the study period, a detailed analysis of NPF events is done in order to get insight into the possible mechanisms and processes involved in NPF events at these contrastive sites. At SNS, NPF is found to be associated with the transport of gaseous precursors from lower altitudes by orographic buoyant upward flows. However, NPF events at SNS site are always observed from the smallest measured sizes of the aerosol size distribution (4 nm), implying that NPF takes place in or in the vicinity of the high-altitude SNS station rather than transported from lower altitudes. Although NPF events at the mountain site seem to be connected with those occurring at the urban site, growth rates (GR) at SNS are higher than those at UGR site (GR7–25 of 6.9 and 4.5 nm h−1 and GR4–7 of 4.1 and 3.6 nm h−1 at SNS and UGR, respectively). This fact could have a special importance on the production of cloud condensation nuclei (CCN) and therefore on cloud formations which may affect regional/global climate, since larger GR at mountain sites could be translated to larger survival probability of NPF particles to reach CCN sizes, due to shorter time needed for the growth. The analysis of sulfuric acid (H2SO4) shows that the contribution of H2SO4 is able to explain a minimal fraction contribution to the observed GRs at both sites (

2020 ◽  
Vol 20 (22) ◽  
pp. 14253-14271 ◽  
Author(s):  
Juan Andrés Casquero-Vera ◽  
Hassan Lyamani ◽  
Lubna Dada ◽  
Simo Hakala ◽  
Pauli Paasonen ◽  
...  

Abstract. A substantial fraction of the atmospheric aerosols originates from secondary new particle formation (NPF), where atmospheric vapours are transformed into particles that subsequently grow to larger sizes, affecting human health and the climate. In this study, we investigate aerosol size distributions at two stations located close to each other (∼ 20 km) but at different altitudes: urban (UGR; 680 m a.s.l., metres above sea level) and high-altitude remote (SNS; 2500 m a.s.l.) sites, both in the area of Granada, Spain, and part of AGORA observatory (Andalusian Global ObseRvatory of the Atmosphere). The analysis shows a significant contribution of nucleation mode aerosol particles to the total aerosol number concentration at both sites, with a contribution of 47 % and 48 % at SNS and UGR, respectively. Due to the important contribution of NPF events to the total aerosol number concentrations and their high occurrence frequency (> 70 %) during the study period, a detailed analysis of NPF events is done in order to get insight into the possible mechanisms and processes involved in NPF events at these contrastive sites. At SNS, NPF is found to be associated with the transport of gaseous precursors from lower altitudes by orographic buoyant upward flows. NPF events at the SNS site are always observed from the smallest measured sizes of the aerosol size distribution (4 nm), implying that NPF takes place in or in the vicinity of the high-altitude SNS station rather than being transported from lower altitudes. Although NPF events at the mountain site seem to be connected with those occurring at the urban site, growth rates (GRs) at SNS are higher than those at the UGR site (GR7−25 of 6.9 and 4.5 nm h−1 and GR4−7 of 4.1 and 3.6 nm h−1 at SNS and UGR, respectively). This fact could have special importance for the production of cloud condensation nuclei (CCN) and therefore for cloud formations which may affect regional/global climate, since larger GRs at mountain sites could translate to a larger survival probability of NPF particles reaching CCN sizes, due to the shorter time period needed for the growth. The analysis of sulfuric acid (H2SO4) shows that the contribution of H2SO4 is able to explain a minimal fraction contribution to the observed GRs at both sites (< 1 % and < 10 % for the 7–25 and 4–7 nm size ranges, respectively), indicating that other condensing vapours are responsible for the majority of particle growth, as well as the differing growth rates between the two sites. Results also show that the condensation sink (CS) does not play a relevant role in NPF processes at both sites and points to the availability of volatile organic compounds (VOCs) as one of the main factors controlling the NPF events at both sites. Finally, a closer analysis of the NPF events that were observed at the SNS site during a Saharan dust episode that occurred during the field campaign was carried out, evidencing the role of TiO2 and F2O3 together with VOCs in promoting new particle formation during this dust intrusion event. Although further investigation is needed to improve our understanding in this topic, this result suggests that climate effects of mineral dust and NPF are not disconnected from each other as it was commonly thought. Therefore, since mineral dust contributes to a major fraction of the global aerosol mass load, dust–NPF interaction should be taken into account in global aerosol-climate modelling for better climate change prediction.


2020 ◽  
Author(s):  
Dominik Stolzenburg ◽  
Runlong Cai ◽  
Lauri Ahonen ◽  
Tiia Laurila ◽  
Sebastian Holm ◽  
...  

&lt;p&gt;New particle formation (NPF) by gas-to-particle conversion occurs frequently in many different environments around the globe (Nieminen et al., 2018). NPF is the major contributor to the global cloud condensation nuclei budget (Gordon et al., 2017) and also impacts urban air quality (Guo et al., 2014). It is therefore crucial to understand how the newly formed particles can survive and grow to larger particles under different environmental conditions. Depending on the environment different condensable vapours and also different aerosol dynamics govern the NPF process.&lt;/p&gt;&lt;p&gt;In order to investigate the dynamics of aerosol growth in the sub-10 nm regime, where the newly formed particles are most vulnerable for losses to pre-existing aerosol, we tested several combining instrument inversion approaches. This allows to combine the measurements of several different particle sizing instruments in the sub-10 nm range, where each instrument offers different benefits and weaknesses. If the instruments are combined during the inversion, this could significantly reduce the error of the inferred particle size-distributions. Model results show that the regularization approach proposed by Wolfenbarger and Seinfeld (1990) yield the most stable inversion for data heavily influenced by measurement errors.&lt;/p&gt;&lt;p&gt;We than apply the tested inversion techniques to measurements in three different environments where an array of different state-of-the-art sub-10 nm sizing instruments was deployed: The SMEAR-II station in Hyyti&amp;#228;l&amp;#228;, Finland, representative for a rural boreal forest background site, the SMEAR-III station in Helsinki, Finland, representative for a medium-polluted middle-scale European city, and at the Beijing University of Chemical Technology, China, an urban site in a global megacity.&lt;/p&gt;&lt;p&gt;We demonstrate that the combining instrument approach can enable a more detailed analysis of the cluster dynamics, e.g. by the application of size- and time resolving growth rate analysis tools (Pichelstorfer et al., 2018). This will lead to a better understanding of the role of coagulation and condensation in the particle growth process and will help to explain the different dynamics which lead to NPF in fundamentally different environments.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;References:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Gordon, H. et al.: Causes and importance of new particle formation in the present-day and preindustrial atmospheres, J. Geophys. Res.-Atmos., 122, doi:10.1002/2017JD026844, 2017.&lt;/p&gt;&lt;p&gt;Guo, S. et al.: Elucidating severe urban haze formation in China, P. Nat. Acad. Sci. USA, 111(49), 17373 LP &amp;#8211; 17378, doi:10.1073/pnas.1419604111, 2014.&lt;/p&gt;&lt;p&gt;Nieminen, T. et al.: Global analysis of continental boundary layer new particle formation based on long-term measurements, Atmos. Chem. Phys., (April), 1&amp;#8211;34, doi:10.5194/acp-2018-304, 2018.&lt;/p&gt;&lt;p&gt;Pichelstorfer, L et al.: Resolving nanoparticle growth mechanisms from size- and time-dependent growth rate analysis, Atmos. Chem. Phys., 18(2), 1307&amp;#8211;1323, doi:10.5194/acp-18-1307-2018, 2018.&lt;/p&gt;&lt;p&gt;Wolfenbarger, J. K. and Seinfeld, J. H.: Inversion of aerosol size distribution data, J. Aerosol Sci., 21(2), 227&amp;#8211;247, doi:https://doi.org/10.1016/0021-8502(90)90007-K, 1990.&lt;/p&gt;


2021 ◽  
Vol 21 (13) ◽  
pp. 9995-10004
Author(s):  
Gang Zhao ◽  
Yishu Zhu ◽  
Zhijun Wu ◽  
Taomou Zong ◽  
Jingchuan Chen ◽  
...  

Abstract. New particle formation (NPF) is thought to contribute half of the global cloud condensation nuclei. A better understanding of the NPF at different altitudes can help assess the impact of NPF on cloud formation and corresponding physical properties. However, NPF is not sufficiently understood in the upper mixing layer because previous studies mainly focused on ground-level measurements. In this study, the developments of aerosol size distribution at different altitudes are characterized based on the field measurement conducted in January 2019 in Beijing, China. We find that the partition of nucleation-mode particles in the upper mixing layer is larger than that at the ground, which implies that the nucleation processing is more likely to happen in the upper mixing layer than that at the ground. Results of the radiative transfer model show that the photolysis rates of the nitrogen dioxide and ozone increase with altitude within the mixing layer, which leads to a higher concentration of sulfuric acid in the upper mixing layer than that at the ground. Therefore, the nucleation processing in the upper mixing layer should be stronger than that at the ground, which is consistent with our measurement results. Our study emphasizes the influence of aerosol–radiation interaction on the NPF. These results have the potential to improve our understanding of the source of cloud condensation nuclei on a global scale due to the impacts of aerosol–radiation interaction.


2010 ◽  
Vol 10 (4) ◽  
pp. 11361-11399 ◽  
Author(s):  
J. Boulon ◽  
K. Sellegri ◽  
H. Venzac ◽  
D. Picard ◽  
E. Weingartner ◽  
...  

Abstract. Aerosol nucleation is an important source of atmospheric particles which have an effect both on the climatic system and on human health. The new particle formation (NPF) process is an ubiquitous phenomenon, yet poorly understood despite the many studies performed on this topic using various approaches (observation, experimentation in smog chambers and modeling). In this work, we investigate the formation of secondary charged aerosols and its climatology at Jungfraujoch, a high altitude site in Swiss Alps (3580 m a.s.l.). Charged particles and clusters (0.5–1.8 nm) were measured within the EUCAARI program from April 2008 to April 2009 and allowed the detection of nucleation events. We found that the aerosol concentration, which is dominated by cluster size class, shows a strong diurnal pattern and that the aerosol size distribution and concentration are strongly influenced by the presence of clouds either during daytime or nighttime conditions. New particle formation events have been investigated and it appears that new particle formation occurs 17.5% of measured days and that the nucleation frequency is strongly linked to air mass origin and path and negatively influenced by cloud presence. In fact, we show that NPF events depend on the occurrence of high concentration VOCs air masses which allowed clusters growing by condensation of organic vapors rather than nucleation of new clusters. Furthermore, the contribution of ions to nucleation process was studied and we found that ion-mediated nucleation (IMN) contribute to 26% of the total nucleation so that ions play an important role in the new particle formation and growth at Jungfraujoch.


2018 ◽  
Author(s):  
Dongjie Shang ◽  
Min Hu ◽  
Jing Zheng ◽  
Yanhong Qin ◽  
Zhuofei Du ◽  
...  

Abstract. Biomass burning (BB) activities have a great impact on particle number size distribution (PNSD) in upper troposphere of Tibet-Plateau, which could affect regional and global climate. The intensive campaign for the measurement of PNSD, gaseous pollutants and meteorological parameters was conducted at Mt. Yulong, a high-altitude site (3410 m a.s.l.) in the southeast of Tibet Plateau during the pre-monsoon season (22 March to 15 April), when the intensive BB activities in South Asia were observed by fire maps. Long-range transport of BB pollutants could increase the accumulation mode particles in background atmosphere of Mt. Yulong. As a consequence, cloud condensation nuclei (CCN) concentration was found to be 2–8 times higher during BB periods than that during clean period. Apart from BB, variation of planet boundary layer (PBL) and new particle formation were other factors that influenced PNSD. However, only 3 NPF events (with a frequency of 14 %) were observed at Mt. Yulong. Occurrence of NPF events during clean episode corresponded with elevated PBL or transported BB pollutants. Due to lack of condensable vapors including sulfuric acid and organic compounds, the newly formed particles were not able to grow to CCN size. Our study emphasized the influences of BB on aerosol and CCN concentration in atmosphere of Tibet Plateau. These results can improve our understanding of the variation of particle concentration in upper troposphere, and provide information for regional and global climate models.


2019 ◽  
Author(s):  
Hing Cho Cheung ◽  
Charles C.-K. Chou ◽  
Celine S. L. Lee ◽  
Wei-Chen Kuo ◽  
Shuenn-Chin Chang

Abstract. The chemical composition of fine particulate matters (PM2.5), the size distribution and number concentration of aerosol particles (NCN) and the number concentration of cloud condensation nuclei (NCCN) were measured at the northern tip of Taiwan Island during a campaign from April 2017 to March 2018. The parameters of aerosol hygroscopicity (i.e. activation ratio, activation diameter and kappa) were retrieved from the measurements. Significant variations were found in the hygroscopicity of aerosols, which were suggested be subject to various pollution sources, including aged air pollutants originating in the eastern/northern China and transported on the Asian continental outflows, fresh particles emitted from local sources and distributed by land-sea breeze circulations as well as produced by new particle formation (NPF) processes. Cluster analysis was applied to the backward trajectories of air masses to investigate their respective source regions. The results showed that the aerosols associated with Asian continental outflows were characterized with higher kappa values, whereas higher NCCN and NCN with lower kappa values were found for aerosols in local air masses. The distinct features in hygroscopicity were consistent with the characteristics in the chemical composition of PM2.5. Moreover, this study revealed that the nucleation mode particles from NPF could have participated in the enhancement of CCN activity, most likely by coagulating with sub-CCN particles, although the freshly produced particles were not favored for CCN activation due to their smaller sizes. Thus, the results of this study suggested that the NPF coupling with coagulation processes can significantly increase the NCCN in atmosphere.


2010 ◽  
Vol 10 (19) ◽  
pp. 9333-9349 ◽  
Author(s):  
J. Boulon ◽  
K. Sellegri ◽  
H. Venzac ◽  
D. Picard ◽  
E. Weingartner ◽  
...  

Abstract. We investigate the formation and growth of charged aerosols clusters at Jungfraujoch, in the Swiss Alps (3580 m a.s.l.), the highest altitude site of the European EUCAARI project intensive campaign. Charged particles and clusters (0.5–1.8 nm) were measured from April 2008 to April 2009 and allowed the detection of nucleation events in this very specific environment (presence of free tropospheric air and clouds). We found that the naturally charged aerosol concentrations, which are dominated by the cluster size class, shows a strong diurnal pattern likely linked to valley breezes transporting surface layer ion precursors, presumably radon. Cosmic rays were found not to be the major ion source at the measurement site. However, at night, when air masses are more representative of free tropospheric conditions, we found that the cluster concentrations are still high. The charged aerosol size distribution and concentration are strongly influenced by the presence of clouds at the station. Clouds should be taken into account when deriving high altitude nucleation statistics. New particle formation occurs on average 17.5% of the measurement period and shows a weak seasonality with a minimum of frequency during winter, but this seasonality is enhanced when the data set is screened for periods when the atmospheric station is out of clouds. The role of ions in the nucleation process was investigated and we found that the ion-mediated nucleation explains 22.3% of the particle formation. The NPF events frequency is correlated with UV radiation but not with calculated H2SO4 concentrations, suggesting that other compounds such as organic vapors are involved in the nucleation and subsequently growth process. In fact, NPF events frequency also surprisingly increases with the condensational sink (CS), suggesting that at Jungfraujoch, the presence of condensing vapours probably coupled with high CS are driving the occurrence of NPF events. A strong link to the air mass path was also pointed out and events were observed to be frequently occurring in Eastern European air masses, which present the highest condensational sink. In these air masses, pre-existing cluster concentrations are more than three time larger than in other air masses during event days, and no new clusters formation is observed, contrarily to what is happening in other air mass types.


2018 ◽  
Author(s):  
Vyoma Singla ◽  
Subrata Mukherjee ◽  
Adam Kristensson ◽  
Govindan Pandithurai ◽  
Kundan K. Dani ◽  
...  

Abstract. There is a lack of characterization of the aerosol population in Western India, how it is affected by meteorological parameters, and new particle formation and the influence on cloud condensation nuclei (CCN). For this reason, measurements of particle number size distribution, aerosol chemical composition, meteorology and cloud condensation nuclei number concentration were monitored at High Altitude Cloud Physics Laboratory (HACPL) in Mahabaleshwar mountain town in Western India between November 2016 and February 2017. Most air masses in this period originated from the Indian continent to the north-east of HACPL. New particle formation (NPF) events were observed on 47 days and mainly associated with these north-easterly air masses and high SO2 emissions and biomass burning activities, while weaker or non-NPF days were associated with westerly air masses and relatively higher influence of local air pollution. The growth of newly formed particles enhanced the mass concentration of secondary organic and inorganic species of aerosol particles. The mean growth rate, formation rate, condensation sink and coagulation loss for the 13 strongest events was found to be 2.58 ± 0.38 nm h−1, 2.82 ± 1.37 cm−3 s−1, 22.3 ± 2.87 * 10-3 s−1 and 1.62 ± 1.04 cm−3 s−1 respectively. A closer examination of 5 events showed that low relative humidity and solar radiation favoured new particle formation. These NPF events lead to a significant increase in CCN concentration (mean ~ 53 ± 36 %). The NanoMap method revealed that NPF took place up to several hundred kilometers upwind and to the north-east of HACPL.


2015 ◽  
Vol 15 (7) ◽  
pp. 10629-10676 ◽  
Author(s):  
V. N. Dos Santos ◽  
E. Herrmann ◽  
H. E. Manninen ◽  
T. Hussein ◽  
J. Hakala ◽  
...  

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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