scholarly journals New particle formation in marine atmosphere during seven cruise campaigns

2018 ◽  
Author(s):  
Yujiao Zhu ◽  
Kai Li ◽  
Yanjie Shen ◽  
Yang Gao ◽  
Xiaohuan Liu ◽  
...  
Keyword(s):  
Long Range ◽  
Particle Number ◽  
Particle Formation ◽  
Long Range Transport ◽  
Northwest Pacific ◽  
Marine Atmosphere ◽  
New Particle Formation ◽  
Marginal Seas ◽  
Range Transport ◽  
New Particles

Abstract. To study the particle number concentration, size distribution and new particle formation (NPF) events in marine atmosphere, we made measurements during six cruise campaigns over the marginal seas of China in 2011–2016 and one campaign from the marginal seas to the Northwest Pacific Ocean (NWPO) in 2014. We observed relatively frequent NPF events in the atmosphere over the marginal seas of China, i.e., 23 out of 126 observational days with the highest occurrence frequency in fall, followed by spring and summer. 22 out of 23 NPF events were analyzed to be associated with the long-range transport of continental pollutants based on 24-hr air mass back trajectories and the preexisting particle number concentrations largely exceeding the clean marine background, leaving one much weaker NPF event to be likely induced by oceanic precursors alone and supported by multiple independent evidences. Although the long-range transport signal of continental pollutants can be clearly observed in the remote marine atmosphere over the NWPO, NPF events were observed only in 2 days out of 36 days. The nucleation mode particles ( 8 cm−3 s−1. The possible mechanisms were argued in terms of roles of different vapor precursors. We also found a ceiling existing for the growth of new particles from 10 nm to larger size in most of NPF events. We thereby introduce a term, i.e., the maximum geometric median diameter of new particles (Dpgmax) and correlate it with the growth rate of new particles (GR). A moderately good linear correlation was also obtained between Dpgmax and GR, and only GR larger than 7.9 nm h−1 can lead to new particles growing with Dpgmax beyond 50 nm. Combining simultaneous measurements of the particle number size distributions and cloud condensation nuclei (CCN) at different super saturations (SS), we indeed observed a clear increase in CCN when the Dpg of new particles exceeded 50 nm at SS = 0.4 %. However, it was not the case for SS = 0.2 %. Consistent with previous studies in continental atmosphere, our results implied that 50 nm can be used as the threshold for new particles to be activated as CCN in the marine atmosphere. Moreover, the κ decreased from 0.4 to 0.1 during the growth period of new particles, implying that organics likely overwhelmed the growth of new particle to CCN size. The chemical analysis of nano-MOUDI samples revealed TMA and oxalic acid may play the important role in the growth of new particles.

scholarly journals New particle formation in the marine atmosphere during seven cruise campaigns

2019 ◽  
Vol 19 (1) ◽  
pp. 89-113 ◽  
Author(s):  
Yujiao Zhu ◽  
Kai Li ◽  
Yanjie Shen ◽  
Yang Gao ◽  
Xiaohuan Liu ◽  
...  
Keyword(s):  
Linear Correlation ◽  
Particle Number ◽  
Number Concentration ◽  
Long Range Transport ◽  
Particle Number Concentration ◽  
Marine Atmosphere ◽  
Marginal Seas ◽  
Range Transport ◽  
Good Linear Correlation ◽  
New Particles

Abstract. We measured the particle number concentration, size distribution, and new particle formation (NPF) events in the marine atmosphere during six cruise campaigns over the marginal seas of China in 2011–2016 and one campaign from the marginal seas to the Northwest Pacific Ocean (NWPO) in 2014. We observed relatively frequent NPF events in the atmosphere over the marginal seas of China, i.e., on 23 out of 126 observational days, with the highest frequency of occurrence in fall, followed by spring and summer. In total, 22 out of 23 NPF events were found to be associated with the long-range transport of continental pollutants based on 24 h air mass back trajectories and pre-existing particle number concentrations, which largely exceeded the clean marine background, leaving one much weaker NPF event that was likely induced by oceanic precursors alone, as supported by multiple independent pieces of evidence. Although the long-range transport signal of continental pollutants can be clearly observed in the remote marine atmosphere over the NWPO, NPF events were observed on only 2 out of 36 days. The nucleation-mode particles (<30 nm), however, accounted for as high as 35 %±13 % of the total particle number concentration during the NWPO cruise campaign, implying the existence of many undetected NPF events in the near-sea-level atmosphere or above. To better characterize NPF events, we introduce a term called the net maximum increase in the nucleation-mode particle number concentration (NMINP) and correlate it with the formation rate of new particles (FR). We find a moderately good linear correlation between NMINP and FR at FR≤8 cm−3 s−1, but no correlation exists at FR>8 cm−3 s−1. The possible mechanisms are argued in terms of the roles of different vapor precursors. We also find that a ceiling exists for the growth of new particles from 10 nm to larger sizes in most NPF events. We thereby introduce a term called the maximum geometric median diameter of new particles (Dpgmax) and correlate it with the growth rate of new particles (GR). A moderately good linear correlation is also obtained between the Dpgmax and GR, and only GR values larger than 7.9 nm h−1 can lead to new particles growing with a Dpgmax beyond 50 nm based on the equation. By combining simultaneous measurements of the particle number size distributions and cloud condensation nuclei (CCN) at different super saturations (SS), we observed a clear increase in CCN when the Dpg of new particles exceeded 50 nm at SS=0.4 %. However, this case did not occur for SS=0.2 %. Consistent with the results of previous studies in the continental atmosphere, our results imply that particles smaller than 50 nm are unlikely activated as CCN at SS=0.4 % in the marine atmosphere. Moreover, κ decrease from 0.4 to 0.1 during the growth period of new particles, implying that organics likely overwhelm the growth of new particles to CCN size. The chemical analysis of nano-Micro-Orifice Uniform Deposit Impactor (nano-MOUDI) samples reveals that trimethylamine (TMA) and oxalic acid might appreciably contribute to the growth of new particles in some cases.

New particle formation under the influence of the long-range transport of air pollutants in East Asia

2016 ◽  
Vol 141 ◽  
pp. 30-40 ◽  
Author(s):  
Indra Chandra ◽  
Seyoung Kim ◽  
Takafumi Seto ◽  
Yoshio Otani ◽  
Akinori Takami ◽  
...  
Keyword(s):  
East Asia ◽  
Long Range ◽  
Air Pollutants ◽  
Particle Formation ◽  
Long Range Transport ◽  
New Particle Formation ◽  
Range Transport

scholarly journals Effects of continental emissions on cloud condensation nuclei (CCN) activity in the northern South China Sea during summertime 2018

2020 ◽  
Vol 20 (15) ◽  
pp. 9153-9167 ◽  
Author(s):  
Mingfu Cai ◽  
Baoling Liang ◽  
Qibin Sun ◽  
Shengzhen Zhou ◽  
Xiaoyang Chen ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Long Range ◽  
Particle Number ◽  
Cloud Condensation Nuclei ◽  
Northern South China Sea ◽  
Long Range Transport ◽  
Marine Atmosphere ◽  
Condensation Nuclei ◽  
Air Masses ◽  
Range Transport

Abstract. Aerosol particles in marine atmosphere have been shown to significantly affect cloud formation, atmospheric optical properties, and climate change. However, high temporally and spatially resolved atmospheric measurements over the sea are currently sparse, limiting our understanding of aerosol properties in marine atmosphere. In this study, a ship-based cruise campaign was conducted over the northern South China Sea (SCS) region during summertime 2018. The chemical composition of non-refractory PM1 (NR-PM1), the particle number size distribution (PNSD), and size-resolved cloud condensation nuclei (CCN) activity were measured by a time-of-flight aerosol chemical speciation monitor (ToF-ACSM) and the combination of a cloud condensation nuclei counter (CCNc) and a scanning mobility particle sizer (SMPS). Overall, aerosol particles exhibited a unimodal distribution centering at 60–80 nm and the chemical composition of the NR-PM1 was dominated by sulfate (∼ 46 %), which likely originated from anthropogenic emissions rather than dimethyl sulfide (DMS) oxidation. Two polluted episodes (P1 and P2) were observed, and both were characterized by high particle number concentrations (NCN) which originated from local emissions and from emissions in inland China via long-range transport. The concentrations of trace gases (i.e., O3, CO, NOx) and particles (NCN and NCCN at ss = 0.34 %) were elevated during P2 at the end of the campaign and decreased with offshore distance, further suggesting important impacts of anthropogenic emissions from the inland Pearl River Delta (PRD) region. Two relatively clean periods (C1 and C2) prior to and after tropical storm Bebinca were classified and the air was affected by air masses from the southwest and from the Indo-Chinese Peninsula, respectively. Chemical composition measurements showed an increase in organic mass fraction during P2 compared to C2; however, no obviously different κ values were obtained from the CCNc measurements, implying that the air masses carried pollutants from local sources during long-range transport. We report an average value of about 0.4 for the aerosol hygroscopicity parameter κ, which falls within the literature values (i.e., 0.2–1.0) for urban and remote marine atmosphere. In addition, our results showed that the CCN fraction (NCCN∕NCN, tot) and the κ values had no clear correlation either with the offshore distance or with concentrations of the particles. Our study highlights dynamical variations in particle properties and the impact of long-range transport from continental China and the Indo-Chinese Peninsula on the northern SCS region during summertime.

scholarly journals Effects of continental emissions on Cloud Condensation Nuclei (CCN) activity in northern South China Sea during summertime 2018

2020 ◽  
Author(s):  
Mingfu Cai ◽  
Baoling Liang ◽  
Qibin Sun ◽  
Shengzhen Zhou ◽  
Bin Yuan ◽  
...  
Keyword(s):  
Long Range ◽  
Particle Number ◽  
Cloud Condensation Nuclei ◽  
Northern South China Sea ◽  
Long Range Transport ◽  
Marine Atmosphere ◽  
Condensation Nuclei ◽  
Air Masses ◽  
Range Transport ◽  
Local Emissions

Abstract. Aerosol particles in marine atmosphere have been shown to significantly affect cloud formation, atmospheric optical properties, and climate change. However, high temporal and spatial resolved atmospheric measurements over sea are currently sparse, limiting our understanding of aerosol properties in marine atmosphere. In this study, a ship-based cruise campaign was conducted over northern South China Sea (SCS) region (19°37′ N to 22°43′ N, 113°44′ E to 118°12′ E) during summertime 2018. Chemical compositions of the non-refractory PM1 (NR-PM1), particle number size distribution (PNSD) and size-resolved cloud condensation nuclei (CCN) activity (at supersaturation ss = 0.18 %, 0.34 %, and 0.59 %) were measured by a time-of-flight aerosol chemical speciation monitor (ToF-ACSM), and the combination of a cloud condensation nuclei counter (CCNc) and a scanning mobility particle sizer (SMPS), respectively. Overall, aerosol particles exhibited a unimodal distribution (centering at 60∼80 nm) and dominated by sulfate (~46 %) in the NR-PM1, similar to the characteristic of previously-reported background marine aerosols. Two polluted episodes were respectively observed at the beginning (P1, 6th–8th August) and at the end (P2, 25th–26th August) of the campaign and both were characterized by high particle number concentrations (NCN) which were shown to originate from local emissions or pollutants from long range transport. Two relatively clean periods (C1, 9th–10th and C2, 19th–21st August) prior to and after tropical storm Bebinca (11th–15th August) were also classified due to substantial removal of pollutants by strong winds and rainfalls accompanying with the storm. A value of about 0.4 for aerosol hygroscopicity parameter κ measured in this study falls in a range of values (i.e., 0.2–1.0) reported previously for urban atmosphere and for remote marine atmosphere. The concentrations of trace gases (i.e., O3, CO, NOX) and particles (NCN and NCCN at ss = 0.34 %) were elevated at the end of the campaign and decreased with the offshore distance, suggesting important impacts of anthropogenic emissions from the inland Pearl River Delta (PRD) region on the northern SCS. A good correlation between NOX concentration and NCN implies similar sources (e.g., heavy ship, traffic, and biomass burning) for NOx and particles. The results showed that the NCCN/NCN,tot and the κ values obtained from the CCNc measurement (ss = 0.34 %) had no clear correlation either with the offshore distance or with the concentrations of the particles. Back trajectory analysis showed that the air pollutants originated from local emissions and from inland China continent via long range transport during P1 and P2, respectively. In addition, the air was affected by air masses from southwest and from Indo-China Peninsula during the clean C1 and C2 periods respectively. Chemical composition measurements showed an increase of organic mass fraction and no obviously different κ values were obtained from CCN measurements during C2 and P2, implying that the air masses carried pollutants from local sources during long range transport from Indo-China Peninsula and from the inland China continent respectively during the above two periods. Our study highlights dynamical variations of particle properties and the impact of long range transport from the China continent and Indo-China Peninsula on the northern SCS region during summertime.

Long-range transport of soot carbon in the marine atmosphere

1984 ◽  
Vol 36 ◽  
pp. 73-80 ◽  
Author(s):  
M.O. Andreae ◽  
T.W. Andreae ◽  
R.J. Ferek ◽  
H. Raemdonck
Keyword(s):  
Long Range ◽  
Long Range Transport ◽  
Marine Atmosphere ◽  
Range Transport ◽  
Soot Carbon

scholarly journals Measurement report: Long-range transport patterns into the tropical northwest Pacific during the CAMP<sup>2</sup>Ex aircraft campaign: chemical composition, size distributions, and the impact of convection

2021 ◽  
Vol 21 (5) ◽  
pp. 3777-3802
Author(s):  
Miguel Ricardo A. Hilario ◽  
Ewan Crosbie ◽  
Michael Shook ◽  
Jeffrey S. Reid ◽  
Maria Obiminda L. Cambaliza ◽  
...  
Keyword(s):  
Long Range ◽  
Southwest Monsoon ◽  
Long Range Transport ◽  
Northwest Pacific ◽  
Back Trajectories ◽  
Air Masses ◽  
China Sea ◽  
Range Transport ◽  
Transport Patterns ◽  
The Impact

Abstract. The tropical Northwest Pacific (TNWP) is a receptor for pollution sources throughout Asia and is highly susceptible to climate change, making it imperative to understand long-range transport in this complex aerosol-meteorological environment. Measurements from the NASA Cloud, Aerosol, and Monsoon Processes Philippines Experiment (CAMP2Ex; 24 August to 5 October 2019) and back trajectories from the National Oceanic and Atmospheric Administration Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) were used to examine transport into the TNWP from the Maritime Continent (MC), peninsular Southeast Asia (PSEA), East Asia (EA), and the West Pacific (WP). A mid-campaign monsoon shift on 20 September 2019 led to distinct transport patterns between the southwest monsoon (SWM; before 20 September) and monsoon transition (MT; after 20 September). During the SWM, long-range transport was a function of southwesterly winds and cyclones over the South China Sea. Low- (high-) altitude air generally came from MC (PSEA), implying distinct aerosol processing related to convection and perhaps wind shear. The MT saw transport from EA and WP, driven by Pacific northeasterly winds, continental anticyclones, and cyclones over the East China Sea. Composition of transported air differed by emission source and accumulated precipitation along trajectories (APT). MC air was characterized by biomass burning tracers while major components of EA air pointed to Asian outflow and secondary formation. Convective scavenging of PSEA air was evidenced by considerable vertical differences between aerosol species but not trace gases, as well as notably higher APT and smaller particles than other regions. Finally, we observed a possible wet scavenging mechanism acting on MC air aloft that was not strictly linked to precipitation. These results are important for understanding the transport and processing of air masses with further implications for modeling aerosol lifecycles and guiding international policymaking to public health and climate, particularly during the SWM and MT.

scholarly journals Three years of aerosol mass, black carbon and particle number concentrations at Montsec (southern~Pyrenees, 1570 m a.s.l.)

2013 ◽  
Vol 13 (10) ◽  
pp. 27201-27241 ◽  
Author(s):  
A. Ripoll ◽  
J. Pey ◽  
M. C. Minguillón ◽  
N. Pérez ◽  
M. Pandolfi ◽  
...  
Keyword(s):  
Solar Radiation ◽  
High Altitude ◽  
Long Range ◽  
Central Europe ◽  
Time Variation ◽  
Particle Number ◽  
Saharan Dust ◽  
Long Range Transport ◽  
Anthropogenic Emissions ◽  
Range Transport

Abstract. Time variation of mass particulate matter (PM1 and PM1−10), black carbon (BC) and particle number (N) concentrations at the high altitude site of Montsec (MSC) in the southern Pyrenees was interpreted for the period 2010–2012. The MSC site registered higher PM10 (12 μg m−3) and N > 7 nm (2209 # cm−3) concentrations than those measured at other high altitude sites in central Europe (PM10: 3–9 μg m−3 and N: 634–2070 # cm−3). By contrast, BC concentrations at MSC (0.2 μg m−3) were equal or even lower than those measured at these European sites (0.2–0.4 μg m−3). These differences were attributed to the lower influence of anthropogenic emissions and to the higher relevance of Saharan dust transport and new particle formation (NPF) processes at MSC. The different time variation of PM and BC concentrations compared with that of N suggests that these aerosol parameters were governed by diverse factors at MSC. Both PM and BC concentrations showed marked differences for different meteorological scenarios, with enhanced concentrations under North African outbreaks (PM1−10: 13 μg m−3, PM1: 8 μg m−3 and BC: 0.3 μg m−3) and low concentrations when Atlantic advections occurred (PM1−10: 5 μg m−3, PM1: 4 μg m−3 and BC: 0.1 μg m−3). Because of the contrasting origin of the air masses in the warmer seasons (spring and summer) and in the colder seasons (autumn and winter), PM and BC concentrations showed a marked increase in summer, with a secondary maximum in early spring, and were at their lowest during winter. The maximum in the warmer seasons was attributed to long-range transport processes which mask the breezes and regional transport breaking the daily cycles of these pollutants. By contrast, PM and BC concentrations showed clear diurnal cycles with maxima at midday in the colder seasons. A statistically significant weekly variation was also obtained for the BC concentrations, displaying a progressive increase from Tuesday to Saturday, followed by a significant decrease on Sunday and Monday. N concentrations depended more on local meteorological variables such as solar radiation than on the air mass origin. Therefore, the highest concentrations of N were associated with summer regional episodes (N > 3 nm: 4461 # cm−3 and N > 7 nm: 3021 # cm−3) and the lowest concentrations were related to winter regional scenarios (N > 3 nm: 2496 # cm−3 and N > 7 nm: 1073 # cm−3). This dependence on solar radiation also accounted for the marked diurnal cycle of N concentrations throughout the year with a peak at midday and for the absence of a weekly pattern. Measurements carried out at MSC enabled us to characterize the tropospheric background aerosols in the Western Mediterranean Basin (WMB). Our results highlight the importance of the NPF processes in southern Europe, reveal much lower anthropogenic emissions than in central Europe, and underline the contribution of natural long-range transport such as Saharan dust.

scholarly journals Simultaneous measurements of new particle formation at 1 s time resolution at a street site and a rooftop site

2017 ◽  
Vol 17 (15) ◽  
pp. 9469-9484 ◽  
Author(s):  
Yujiao Zhu ◽  
Caiqing Yan ◽  
Renyi Zhang ◽  
Zifa Wang ◽  
Mei Zheng ◽  
...  
Keyword(s):  
Time Resolution ◽  
Particle Number ◽  
Formation Rate ◽  
Particle Formation ◽  
Photochemical Reactions ◽  
Urban Atmosphere ◽  
New Particle Formation ◽  
Gaseous Species ◽  
A Site ◽  
New Particles

Abstract. This study is the first to use two identical Fast Mobility Particle Sizers for simultaneous measurement of particle number size distributions (PNSDs) at a street site and a rooftop site within 500 m distance in wintertime and springtime to investigate new particle formation (NPF) in Beijing. The collected datasets at 1 s time resolution allow deduction of the freshly emitted traffic particle signal from the measurements at the street site and thereby enable the evaluation of the effects on NPF in an urban atmosphere through a site-by-site comparison. The number concentrations of 8 to 20 nm newly formed particles and the apparent formation rate (FR) in the springtime were smaller at the street site than at the rooftop site. In contrast, NPF was enhanced in the wintertime at the street site with FR increased by a factor of 3 to 5, characterized by a shorter NPF time and higher new particle yields than at the rooftop site. Our results imply that the street canyon likely exerts distinct effects on NPF under warm or cold ambient temperature conditions because of on-road vehicle emissions, i.e., stronger condensation sinks that may be responsible for the reduced NPF in the springtime but efficient nucleation and partitioning of gaseous species that contribute to the enhanced NPF in the wintertime. The occurrence or absence of apparent growth for new particles with mobility diameters larger than 10 nm was also analyzed. The oxidization of biogenic organics in the presence of strong photochemical reactions is suggested to play an important role in growing new particles with diameters larger than 10 nm, but sulfuric acid is unlikely to be the main species for the apparent growth. However, the number of datasets used in this study is relatively small, and larger datasets are essential to draw a general conclusion.

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