Vertical and horizontal distribution of regional new particle formation events in Madrid

Abstract. The vertical profile of new particle formation (NPF) events was studied by comparing the aerosol size number distributions measured aloft and at surface level in a suburban environment in Madrid, Spain, using airborne instruments. The horizontal distribution and regional impact of the NPF events was investigated with data from three urban, urban background, and suburban stations in the Madrid metropolitan area. Intensive regional NPF episodes followed by particle growth were simultaneously recorded at three stations in and around Madrid during a field campaign in July 2016. The urban stations presented larger formation rates compared to the suburban station. Condensation and coagulation sinks followed a similar evolution at all stations, with higher values at urban stations. However, the total number concentration of particles larger than 2.5 nm was lower at the urban station and peaked around noon, when black carbon (BC) levels are at a minimum. The vertical soundings demonstrated that ultrafine particles (UFPs) are formed exclusively inside the mixed layer. As convection becomes more effective and the mixed layer grows, UFPs are detected at higher levels. The morning soundings revealed the presence of a residual layer in the upper levels in which aged particles (nucleated and grown on previous days) prevail. The particles in this layer also grow in size, with growth rates significantly smaller than those inside the mixed layer. Under conditions with strong enough convection, the soundings revealed homogeneous number size distributions and growth rates at all altitudes, which follow the same evolution at the other stations considered in this study. This indicates that UFPs are detected quasi-homogenously in an area spanning at least 17 km horizontally. The NPF events extend over the full vertical extension of the mixed layer, which can reach as high as 3000 m in the area, according to previous studies. On some days a marked decline in particle size (shrinkage) was observed in the afternoon, associated with a change in air masses. Additionally, a few nocturnal nucleation-mode bursts were observed at the urban stations, for which further research is needed to elucidate their origin.

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Vertical and horizontal distribution of regional new particle formation events in Madrid

10.5194/acp-2018-173 ◽

2018 ◽

Cited By ~ 1

Author(s):

Cristina Carnerero ◽

Noemí Pérez ◽

Cristina Reche ◽

Marina Ealo ◽

Gloria Titos ◽

...

Keyword(s):

Mixed Layer ◽

Growth Rates ◽

Ultrafine Particles ◽

Total Concentration ◽

Particle Formation ◽

Horizontal Distribution ◽

New Particle Formation ◽

Vehicle Exhaust ◽

Radiative Balance ◽

The Impact

Abstract. The vertical profile of new particle formation (NPF) events was studied by comparing the aerosol size number distributions measured aloft and at surface level in a suburban environment in Madrid, Spain using airborne instruments. The horizontal distribution and regional impact of the NPF events was investigated with data from three urban and suburban stations in the Madrid metropolitan area. Intensive regional NPF episodes followed by particle growth were simultaneously recorded at three stations in and around Madrid, in a field campaign in July 2016. On some days a marked decline in particle size (shrinkage) was observed in the afternoon, associated with a change in air masses. Additionally, a few nocturnal nucleation mode bursts were observed in the urban stations, which could be related to aircraft emissions transported from the airport. Considering all simultaneous diurnal NPF events registered, growth rates were significantly lower at the urban stations, ranging 2.0–3.9 nm h−1, compared to the suburban station (2.9–10.0 nm h−1). Total concentration of 9.1–25 nm particles reached 2.8 x 104 cm−3 at the urban station and 1.7 x 104 cm−3 at the suburban station, the mean daily values being 3.7 x 104 cm−3 (2.2 x 104 cm−3 at the suburban station) during event days. The formation rates of 9–25 nm particles peaked around noon and recorded a median value of 2.0 cm−3 s−1 and 1.1 cm−3 s−1 at the urban and suburban stations, respectively. The condensation and coagulation sinks presented minimum values shortly before sunrise, increasing after dawn reaching the maximum value at 14:00 UTC, with average daily mean values of 3.4 x 10−3 s−1 (2.5 x 10−3 s−1 at the suburban station) and 2.4 x 10−5 s−1, respectively, during event days. The vertical soundings demonstrated that ultrafine particles (UFP) are transported from surface levels to higher levels, thus newly-formed particles ascend from surface to the top of the mixing layer. The morning soundings revealed the presence of a residual layer in the upper levels in which aged particles (nucleated and grown on previous days) prevail. The particles in this layer also grow in size, with growth rates significantly smaller than those inside the mixed layer. Under conditions with strong enough convection, the soundings revealed homogeneous number size distributions and growth rates at all altitudes, which follow the same evolution in the other stations considered in this study. This indicates that NPF occurs quasi-homogenously in an area spanning at least 17 km horizontally. The NPF events extend over the full vertical extension of the mixed layer reaching as high as 3000 m. This can have consequences in the radiative balance of the atmosphere and affect the climate. Results also evidenced that total particle concentration in and around Madrid in summer is dominated by NPF during summer, thus it may obscure the impact of vehicle exhaust emissions on levels of UFP.

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Analysis of New Particle Formation (NPF) Events at Nearby Rural, Urban Background and Urban Roadside Sites

10.5194/acp-2018-1057 ◽

2018 ◽

Cited By ~ 1

Author(s):

Dimitrios Bousiotis ◽

Manuel Dall’Osto ◽

David C. S. Beddows ◽

Francis D. Pope ◽

Roy M. Harrison

Keyword(s):

Growth Rates ◽

Ultrafine Particles ◽

General Pattern ◽

Particle Growth ◽

Particle Formation ◽

Atmospheric Conditions ◽

New Particle Formation ◽

Urban Background ◽

Air Masses ◽

Condensation Sink

Abstract. NPF events have different patterns of development depending on the conditions of the area in which they occur. In this study, NPF events occurring at three sites of differing characteristics (rural Harwell (HAR), urban background North Kensington (NK), urban roadside Marylebone Road (MR), London, UK) were studied (seven years of data). The different atmospheric conditions in each study area not only have an effect on the frequency of the events, but also affect their development. The frequency of NPF events is similar at the rural and urban background locations (about 7 % of days), with a high proportion of events occurring at both sites on the same day (45 %). The frequency of NPF events at the urban roadside site is slightly less (6 % of days), and higher particle growth rates (average 5.5 nm h−1 at MR compared to 3.4 nm h−1 and 4.2 nm h−1 at HAR and NK respectively) must result from rapid gas to particle conversion of traffic-generated pollutants. A general pattern is found in which the condensation sink increases with the degree of pollution of the site, but this is counteracted by increased particle growth rates at the more polluted location. A key finding of this study is that the role of the urban environment leads to an increment of 20 % in N16–20 nm in the urban background compared to that of the rural area in NPF events occurring at both sites. The relationship of the origin of incoming air masses is also considered and an association of regional events with cleaner air masses is found. Due to lower availability of condensable species, NPF events that are associated with cleaner atmospheric conditions have lower growth rates of the newly formed particles. The decisive effect of the condensation sink in the development of NPF events and the survivability of the newly formed particles is underlined, and influences the overall contribution of NPF events to the number of ultrafine particles in an area. The other key factor identified by this study is the important role that urban pollution plays in new particle formation events.

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Climatology of new particle formation at Izaña mountain GAW observatory in the subtropical North Atlantic

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-3865-2014 ◽

2014 ◽

Vol 14 (8) ◽

pp. 3865-3881 ◽

Cited By ~ 21

Author(s):

M. I. García ◽

S. Rodríguez ◽

Y. González ◽

R. D. García

Keyword(s):

Sulfuric Acid ◽

North Atlantic ◽

Growth Rates ◽

Particle Growth ◽

Particle Formation ◽

Dust Particles ◽

New Particle Formation ◽

Data Set ◽

Mean Values ◽

Condensation Sink

Abstract. A climatology of new particle formation (NPF) events at high altitude in the subtropical North Atlantic is presented. A 4-year data set (June 2008–June 2012), which includes number size distributions (10–600 nm), reactive gases (SO2, NOx, and O3), several components of solar radiation and meteorological parameters, measured at Izaña Global Atmosphere Watch (GAW) observatory (2373 m above sea level; Tenerife, Canary Islands) was analysed. NPF is associated with the transport of gaseous precursors from the boundary layer by orographic buoyant upward flows that perturb the low free troposphere during daytime. On average, 30% of the days contained an NPF event. Mean values of the formation and growth rates during the study period were 0.46 cm−3 s−1 and 0.42 nm h−1, correspondingly. There is a clearly marked NPF season (May–August), when these events account for 50–60% of the days per month. Monthly mean values of the formation and growth rates exhibit higher values in this season, 0.49–0.92 cm−3 s−1 and 0.48–0.58 nm h−1, respectively. During NPF events, SO2, UV radiation and upslope winds showed higher values than during non-events. The overall data set indicates that SO2 plays a key role as precursor, although other species seem to contribute during some periods. Condensation of sulfuric acid vapour accounts for most of the measured particle growth during most of the year (~70%), except for some periods. In May, the highest mean growth rates (~0.6 nm h−1) and the lowest contribution of sulfuric acid (~13%) were measured, suggesting a significant involvement of other condensing vapours. The SO2 availability seems also to be the most influencing parameter in the year-to-year variability in the frequency of NPF events. The condensation sink showed similar features to other mountain sites, showing high values during NPF events. Summertime observations, when Izaña is within the Saharan Air Layer, suggest that dust particles may play a significant role acting as coagulation sink of freshly formed nucleation particles. The contribution of dust particles to the condensation sink of sulfuric acid vapours seems to be modest (~8% as average). Finally, we identified a set of NPF events in which two nucleation modes, which may evolve at different rates, occur simultaneously and for which further investigations are necessary.

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New particle formation in air mass transported between two measurement sites in Northern Finland

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-11929-2005 ◽

2005 ◽

Vol 5 (6) ◽

pp. 11929-11963 ◽

Cited By ~ 1

Author(s):

M. Komppula ◽

S.-L. Sihto ◽

H. Korhonen ◽

H. Lihavainen ◽

V.-M. Kerminen ◽

...

Keyword(s):

Growth Rates ◽

Particle Growth ◽

Particle Formation ◽

Distribution Data ◽

New Particle Formation ◽

Air Mass ◽

Air Masses ◽

Aerosol Dynamics ◽

Almost All ◽

Distinct Features

Abstract. This study covers four years of aerosol number size distribution data from Pallas and Värriö sites 250 km apart from each other in Northern Finland and compares new particle formation events between these sites. In eastern air masses almost all events were observed to start earlier at the eastern station Värriö, whereas in western air masses most of the events were observed to start earlier at the western station Pallas. This demonstrates that particle formation in a certain air mass type depends not only on the diurnal variation of the parameters causing the phenomenon (such as photochemistry) but also on some properties carried by the air mass itself. The correlation in growth rates between the two sites was relatively good, which suggests that the amount of condensable vapour causing the growth must have been at about the same level in both sites. The value of condensation sink was frequently much higher at the downwind station. It seems that secondary particle formation related to biogenic sources dominate in many cases over the particle sinks during the air mass transport between the sites. Two cases of transport from Pallas to Värriö were further analysed with an aerosol dynamics model. The model was able to reproduce the observed nucleation events 250 km down-wind at Värriö but revealed some differences between the two cases. The simulated nucleation rates were in both cases similar but the organic concentration profiles that best reproduced the observations were different in the two cases indicating that divergent formation reactions may dominate under different conditions. The simulations also suggested that organic compounds were the main contributor to new particle growth, which offers a tentative hypothesis to the distinct features of new particles at the two sites: Air masses arriving from Atlantic Ocean typically spent approximately only ten hours over land before arriving at Pallas, and thus the time for the organic vapours to accumulate in the air and to interact with the particles is relatively short. This can lead to low nucleation mode growth rates and even to suppression of detectable particle formation event due to efficient scavenging of newly formed clusters, as was observed in the case studies.

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Basic characteristics of atmospheric particles, trace gases and meteorology in a relatively clean Southern African Savannah environment

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-8-6313-2008 ◽

2008 ◽

Vol 8 (2) ◽

pp. 6313-6353 ◽

Cited By ~ 1

Author(s):

L. Laakso ◽

H. Laakso ◽

P. P. Aalto ◽

P. Keronen ◽

T. Petäjä ◽

...

Keyword(s):

Growth Rates ◽

Cloud Condensation Nuclei ◽

Regional Climate ◽

Formation Rate ◽

Measurement Data ◽

Particle Growth ◽

Particle Formation ◽

New Particle Formation ◽

Total Particle ◽

Pm2.5 And Pm10

Abstract. We have analyzed one year (July 2006–July 2007) of measurement data from a relatively clean background site located in dry savannah in South Africa. The annual-median trace gas concentrations were equal to 0.7 ppb for SO2, 1.4 ppb for NOx, 36 ppb for O3 and 105 ppb for CO. The corresponding PM1, PM2.5 and PM10 concentrations were 9.0, 10.5 and 18.8 μg m−3, and the annual median total particle number concentration in the size range 10–840 nm was 2340 cm−3. Gases and particles had a clear seasonal and diurnal variation, which was associated with field fires and biological activity together with local meteorology. Atmospheric new-particle formation was observed to take place in more than 90% of the analyzed days. The days with no new particle formation were cloudy or rainy days. The formation rate of 10 nm particles varied in the range of 0.1–28 cm−3 s−1 (median 1.9 cm−3 s−1) and nucleation mode particle growth rates were in the range 3–21 nm h−1 (median 8.5 nm h−1). Due to high formation and growth rates, observed new particle formation gives a significant contribute to the number of cloud condensation nuclei budget, having a potential to affect the regional climate forcing patterns.

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Analysis of new particle formation (NPF) events at nearby rural, urban background and urban roadside sites

Atmospheric Chemistry and Physics ◽

10.5194/acp-19-5679-2019 ◽

2019 ◽

Vol 19 (8) ◽

pp. 5679-5694 ◽

Cited By ~ 8

Author(s):

Dimitrios Bousiotis ◽

Manuel Dall'Osto ◽

David C. S. Beddows ◽

Francis D. Pope ◽

Roy M. Harrison

Keyword(s):

Urban Environment ◽

Growth Rates ◽

General Pattern ◽

Particle Growth ◽

Particle Formation ◽

Atmospheric Conditions ◽

New Particle Formation ◽

Urban Background ◽

Air Masses ◽

Condensation Sink

Abstract. New particle formation (NPF) events have different patterns of development depending on the conditions of the area in which they occur. In this study, particle size distributions in the range of 16.6–604 nm (7 years of data) were analysed and NPF events occurring at three sites of differing characteristics – rural Harwell (HAR), urban background North Kensington (NK), urban roadside Marylebone Road (MR), London, UK – were extracted and studied. The different atmospheric conditions in each study area not only have an effect on the frequency of the events, but also affect their development. The frequency of NPF events is similar at the rural and urban background locations (about 7 % of days), with a high proportion of events occurring at both sites on the same day (45 %). The frequency of NPF events at the urban roadside site is slightly less (6 % of days), and higher particle growth rates (average 5.5 nm h−1 at MR compared to 3.4 and 4.2 nm h−1 at HAR and NK respectively) must result from rapid gas-to-particle conversion of traffic-generated pollutants. A general pattern is found in which the condensation sink increases with the degree of pollution of the site, but this is counteracted by increased particle growth rates at the more polluted location. A key finding of this study is that the role of the urban environment leads to an increment of 20 % in N16–20 nm in the urban background compared to that of the rural area in NPF events occurring at both sites. The relationship of the origin of incoming air masses is also considered and an association of regional events with cleaner air masses is found. Due to lower availability of condensable species, NPF events that are associated with cleaner atmospheric conditions have lower growth rates of the newly formed particles. The decisive effect of the condensation sink in the development of NPF events and the survivability of the newly formed particles is underlined, and influences the overall contribution of NPF events to the number of ultrafine particles in an area. The other key factor identified by this study is the important role that pollution, both from traffic and other sources in the urban environment (such as heating or cooking), plays in new particle formation events.

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An improved criterion for new particle formation in diverse atmospheric environments

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-8469-2010 ◽

2010 ◽

Vol 10 (17) ◽

pp. 8469-8480 ◽

Cited By ~ 105

Author(s):

C. Kuang ◽

I. Riipinen ◽

S.-L. Sihto ◽

M. Kulmala ◽

A. V. McCormick ◽

...

Keyword(s):

Sulfuric Acid ◽

Growth Rates ◽

Particle Growth ◽

Particle Formation ◽

Balance Model ◽

New Particle Formation ◽

Data Set ◽

Surface Areas ◽

Recent Developments ◽

Diverse Data

Abstract. A dimensionless theory for new particle formation (NPF) was developed, using an aerosol population balance model incorporating recent developments in nucleation rates and measured particle growth rates. Based on this theoretical analysis, it was shown that a dimensionless parameter LΓ, characterizing the ratio of the particle scavenging loss rate to the particle growth rate, exclusively determined whether or not NPF would occur on a particular day. This parameter determines the probability that a nucleated particle will grow to a detectable size before being lost by coagulation with the pre-existing aerosol. Cluster-cluster coagulation was shown to contribute negligibly to this survival probability under conditions pertinent to the atmosphere. Data acquired during intensive measurement campaigns in Tecamac (MILAGRO), Atlanta (ANARChE), Boulder, and Hyytiälä (QUEST II, QUEST IV, and EUCAARI) were used to test the validity of LΓ as an NPF criterion. Measurements included aerosol size distributions down to 3 nm and gas-phase sulfuric acid concentrations. The model was applied to seventy-seven NPF events and nineteen non-events (characterized by growth of pre-existing aerosol without NPF) measured in diverse environments with broad ranges in sulfuric acid concentrations, ultrafine number concentrations, aerosol surface areas, and particle growth rates (nearly two orders of magnitude). Across this diverse data set, a nominal value of LΓ=0.7 was found to determine the boundary for the occurrence of NPF, with NPF occurring when LΓ<0.7 and being suppressed when LΓ>0.7. Moreover, nearly 45% of measured LΓ values associated with NPF fell in the relatively narrow range of 0.1

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An improved criterion for new particle formation in diverse atmospheric environments

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-491-2010 ◽

2010 ◽

Vol 10 (1) ◽

pp. 491-521 ◽

Cited By ~ 3

Author(s):

C. Kuang ◽

I. Riipinen ◽

S.-L. Sihto ◽

M. Kulmala ◽

A. V. McCormick ◽

...

Keyword(s):

Sulfuric Acid ◽

Growth Rates ◽

Particle Growth ◽

Particle Formation ◽

Balance Model ◽

New Particle Formation ◽

Data Set ◽

Surface Areas ◽

Recent Developments ◽

Diverse Data

Abstract. A dimensionless theory for new particle formation (NPF) was developed, using an aerosol population balance model incorporating recent developments in nucleation rates and measured particle growth rates. Based on this theoretical analysis, it was shown that a dimensionless parameter LΓ, characterizing the ratio of the particle scavenging loss rate to the particle growth rate, exclusively determined whether or not NPF would occur on a particular day. This parameter determines the probability that a nucleated particle will grow to a detectable size before being lost by coagulation with the pre-existing aerosol. Cluster-cluster coagulation was shown to contribute negligibly to this survival probability under conditions pertinent to the atmosphere. Data acquired during intensive measurement campaigns in Tecamac (MILAGRO), Atlanta (ANARChE), Boulder, and Hyytiälä (QUEST II, QUEST IV, and EUCAARI) were used to test the validity of LΓ as an NPF criterion. Measurements included aerosol size distributions down to 3 nm and gas-phase sulfuric acid concentrations. The model was applied to seventy-seven NPF events and nineteen non-events (characterized by growth of pre-existing aerosol without NPF) measured in diverse environments with broad ranges in sulfuric acid concentrations, ultrafine number concentrations, aerosol surface areas, and particle growth rates (nearly two orders of magnitude). Across this diverse data set, a nominal value of LΓ=0.7 was found to determine the boundary for the occurrence of NPF, with NPF occurring when LΓ<0.7 and being suppressed when LΓ> 0.7. Moreover, nearly 45% of measured LΓ values associated with NPF fell in the relatively narrow range of 0.1<LΓ<0.3.

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