scholarly journals Urban aerosol size distributions over the Mediterranean city of Barcelona, NE Spain

2012 ◽  
Vol 12 (7) ◽  
pp. 16457-16492 ◽  
Author(s):  
M. Dall'Osto ◽  
D.C.S. Beddows ◽  
J. Pey ◽  
S. Rodriguez ◽  
A. Alastuey ◽  
...  
Keyword(s):  
Particle Number ◽  
Number Concentration ◽  
Aerosol Size Distribution ◽  
Time Variability ◽  
Small Contribution ◽  
Particle Number Concentration ◽  
Size Distributions ◽  
Total Particle Number ◽  
Total Particle ◽  
One Year

Abstract. Differential mobility particle sizer (DMPS) aerosol concentrations (N13–800) were collected over a one-year-period (2004) at an urban background site in Barcelona, North-Eastern Spain. Quantitative contributions to particle number concentrations of the nucleation (33–38%), Aitken (39–49%) and accumulation mode (18–22%) were estimated. We examined the source and time variability of atmospheric aerosol particles by using both K-means clustering and Positive Matrix Factorization (PMF) analysis. Performing clustering analysis on hourly size distributions, nine K-means DMPS clusters were identified and, by directional association, diurnal variation and relationship to meteorological and pollution variables, four typical aerosol size distribution scenarios were identified: traffic (69% of the time), dilution (15% of the time), summer background conditions (4% of the time) and regional pollution (12% of the time). According to the results of PMF, vehicle exhausts are estimated to contribute at least to 62–66% of the total particle number concentration, with a slightly higher proportion distributed towards the nucleation mode (34%) relative to the Aitken mode (28–32%). Photochemically induced nucleation particles make only a small contribution to the total particle number concentration (2–3% of the total), although only particles larger than 13 nm were considered in this study. Overall the combination of the two statistical methods is successful at separating components and quantifying relative contributions to the particle number population.

scholarly journals Urban aerosol size distributions over the Mediterranean city of Barcelona, NE Spain

2012 ◽  
Vol 12 (22) ◽  
pp. 10693-10707 ◽  
Author(s):  
M. Dall'Osto ◽  
D.C.S. Beddows ◽  
J. Pey ◽  
S. Rodriguez ◽  
A. Alastuey ◽  
...  
Keyword(s):  
Particle Number ◽  
Number Concentration ◽  
Aerosol Size Distribution ◽  
Time Variability ◽  
Small Contribution ◽  
Particle Number Concentration ◽  
Size Distributions ◽  
Total Particle Number ◽  
Total Particle ◽  
One Year

Abstract. Differential mobility particle sizer (DMPS) aerosol concentrations (N13-800) were collected over a one-year-period (2004) at an urban background site in Barcelona, North-Eastern Spain. Quantitative contributions to particle number concentrations of the nucleation (33–39%), Aitken (39–49%) and accumulation mode (18–22%) were estimated. We examined the source and time variability of atmospheric aerosol particles by using both K-means clustering and Positive Matrix Factorization (PMF) analysis. Performing clustering analysis on hourly size distributions, nine K-means DMPS clusters were identified and, by directional association, diurnal variation and relationship to meteorological and pollution variables, four typical aerosol size distribution scenarios were identified: traffic (69% of the time), dilution (15% of the time), summer background conditions (4% of the time) and regional pollution (12% of the time). According to the results of PMF, vehicle exhausts are estimated to contribute at least to 62–66% of the total particle number concentration, with a slightly higher proportion distributed towards the nucleation mode (34%) relative to the Aitken mode (28–32%). Photochemically induced nucleation particles make only a small contribution to the total particle number concentration (2–3% of the total), although only particles larger than 13 nm were considered in this study. Overall the combination of the two statistical methods is successful at separating components and quantifying relative contributions to the particle number population.

scholarly journals Comparison between summertime and wintertime Arctic Ocean primary marine aerosol properties

2013 ◽  
Vol 13 (9) ◽  
pp. 4783-4799 ◽  
Author(s):  
J. Zábori ◽  
R. Krejci ◽  
J. Ström ◽  
P. Vaattovaara ◽  
A. M. L. Ekman ◽  
...  
Keyword(s):  
Sea Ice ◽  
Water Temperature ◽  
Arctic Ocean ◽  
Particle Number ◽  
Number Concentration ◽  
The Arctic ◽  
Particle Number Concentration ◽  
Size Distributions ◽  
Total Particle Number ◽  
Total Particle

Abstract. Primary marine aerosols (PMAs) are an important source of cloud condensation nuclei, and one of the key elements of the remote marine radiative budget. Changes occurring in the rapidly warming Arctic, most importantly the decreasing sea ice extent, will alter PMA production and hence the Arctic climate through a set of feedback processes. In light of this, laboratory experiments with Arctic Ocean water during both Arctic winter and summer were conducted and focused on PMA emissions as a function of season and water properties. Total particle number concentrations and particle number size distributions were used to characterize the PMA population. A comprehensive data set from the Arctic summer and winter showed a decrease in PMA concentrations for the covered water temperature (Tw) range between −1°C and 15°C. A sharp decrease in PMA emissions for a Tw increase from −1°C to 4°C was followed by a lower rate of change in PMA emissions for Tw up to about 6°C. Near constant number concentrations for water temperatures between 6°C to 10°C and higher were recorded. Even though the total particle number concentration changes for overlapping Tw ranges were consistent between the summer and winter measurements, the distribution of particle number concentrations among the different sizes varied between the seasons. Median particle number concentrations for a dry diameter (Dp< 0.125μm measured during winter conditions were similar (deviation of up to 3%), or lower (up to 70%) than the ones measured during summer conditions (for the same water temperature range). For Dp > 0.125μm, the particle number concentrations during winter were mostly higher than in summer (up to 50%). The normalized particle number size distribution as a function of water temperature was examined for both winter and summer measurements. An increase in Tw from −1°C to 10°C during winter measurements showed a decrease in the peak of relative particle number concentration at about a Dp of 0.180μm, while an increase was observed for particles with Dp > 1μm. Summer measurements exhibited a relative shift to smaller particle sizes for an increase of Tw in the range 7–11°C. The differences in the shape of the number size distributions between winter and summer may be caused by different production of organic material in water, different local processes modifying the water masses within the fjord (for example sea ice production in winter and increased glacial meltwater inflow during summer) and different origin of the dominant sea water mass. Further research is needed regarding the contribution of these factors to the PMA production.

scholarly journals A concept of an automated function control for ambient aerosol measurements using mobility particle size spectrometers

2013 ◽  
Vol 6 (6) ◽  
pp. 10551-10570
Author(s):  
A. Schladitz ◽  
M. Merkel ◽  
S. Bastian ◽  
W. Birmili ◽  
K. Weinhold ◽  
...  
Keyword(s):  
Particle Size ◽  
Air Quality ◽  
Particle Number ◽  
Zero Point ◽  
Number Concentration ◽  
Quality Monitoring ◽  
Particle Number Concentration ◽  
Air Quality Monitoring ◽  
Total Particle Number ◽  
Total Particle

Abstract. An automated function control unit was developed to regularly check the ambient particle number concentration derived from a mobility particle size spectrometer as well as its zero-point behaviour. The aim of the new feature is to conduct unattended quality control experiments under field conditions at remote air quality monitoring or research stations. The automated function control also has the advantage of being able to get a faster system stability response than the recommended on-site comparisons with reference instruments. The method is based on a comparison of the total particle number concentration measured by a mobility particle size spectrometer and a condensation particle counter removing the diffusive particles approximately smaller than 25 nm in diameter. In practice, the small particles are removed by a set of diffusion screens, as traditionally used in a diffusion battery. The other feature of the automated function control is to check the zero-point behaviour of the ambient aerosol passing through a high-efficiency particulate air (HEPA) filter. An exemplary one-year data set is presented for the measurement site Annaberg-Buchholz as part of the Saxon air quality monitoring network. The total particle number concentration derived from the mobility particle size spectrometer overestimates the particle number concentration by only 2% (grand average offset). Furthermore, tolerance criteria are presented to judge the performance of the mobility particle size spectrometer with respect to the particle number concentration. An upgrade of a mobility particle size spectrometer with an automated function control enhances the quality of long-term particle number size distribution measurements. Quality assured measurements are a precondition for intercomparison studies of different sites. Comparable measurements will improve cohort health and also climate-relevant research studies.

scholarly journals Contribution of ship traffic to aerosol particle concentrations downwind of a major shipping lane

2014 ◽  
Vol 14 (6) ◽  
pp. 8419-8454 ◽  
Author(s):  
N. Kivekäs ◽  
A. Massling ◽  
H. Grythe ◽  
R. Lange ◽  
V. Rusnak ◽  
...  
Keyword(s):  
Mass Concentration ◽  
Particle Number ◽  
Number Concentration ◽  
Anthropogenic Source ◽  
Western Coast ◽  
Particle Number Concentration ◽  
Ship Emissions ◽  
Background Values ◽  
Total Particle Number ◽  
Total Particle

Abstract. Particles in the atmosphere are of concern due to their toxic properties and effects on climate. In coastal areas ship emissions can be a significant anthropogenic source. In this study we investigated the contribution from ship emissions to the total particle number and mass concentrations at a remote location. We studied the particle number concentration (12 to 490 nm in diameter), the mass concentration (12 to 150 nm in diameter) and number and volume size distribution of aerosol particles in ship plumes for a period of four and a half months at Høvsøre, a coastal site on the western coast of Jutland in Denmark. During episodes of western winds the site is about 50 km downwind of a major shipping lane and the plumes are approximately one hour aged when they arrive at the site. We have used a sliding percentile based method for separating the plumes from the measured background values and to calculate the ship plume contribution to the total particle number and PM0.15 mass concentration (mass of particles below 150 nm in diameter, converted from volume assuming sphericity) at the site. The method is not limited to particle number or volume concentration, but can also be used for different chemical species in both particle and gas phase. The total number of analyzed ship plumes was 726, covering on average 19% of the time when air masses were arriving to the site over the shipping lane. During the periods when plumes were present, the particle concentration exceeded the background values on average by 790 cm−3 by number and 0.10 μg m−3 by mass. The corresponding daily average values were 170 cm−3 and 0.023 μg m−3, respectively. This means that the ship plumes contributed between 11 and 19% to the particle number concentration, and between 9 and 18% to PM0.15 during days when air was arriving over the shipping lane. The estimated annual contribution from ship plumes, where all wind directions were included, was in the range of 5–8% in particle number concentration and 4–8% in PM0.15.

Global variability of aerosol physical properties retrieved from the network of GAW near-surface observatories

2020 ◽  
Author(s):  
Clémence Rose ◽  
Keyword(s):  
Physical Properties ◽  
Particle Number ◽  
Number Concentration ◽  
Particle Number Concentration ◽  
Near Surface ◽  
Total Particle Number ◽  
Total Particle ◽  
Surface Measurements ◽  
Boundary Layer Dynamics ◽  
Aerosol Properties

&lt;p&gt;Due to their multiple effects on climate and human health, aerosol particles are a key component of the Earth&amp;#8217;s atmosphere. The understanding of these effects however remains incomplete, which in turn affects their quantification at the present time as well as future predictions. These limitations highlight the need for continuing the efforts to organize long term monitoring of the climate-relevant aerosol properties in as broad a network as possible.&lt;/p&gt;&lt;p&gt;The value of such measurements, which are performed in compliance with homogenous protocols and meet high quality standards, is clearly demonstrated in the present analysis. This work, which is focused on the particle number concentration and particle number size distribution (PNSD), is part of a wider project, one of the objectives of which is to document the variability of climate-relevant aerosol properties based on available in-situ near-surface measurements. To investigate the spatial variability of the abovementioned aerosol physical properties, observations collected at 57 sites connected to the Global Atmosphere Watch (GAW) network were analysed for a reference year (2017). Measurements performed with condensation particle counters (CPC, 21 sites) and mobility particle size spectrometers (MPSS, 36 sites) were both included in the analysis; in the latter case, the total particle number concentration, N&lt;sub&gt;tot&lt;/sub&gt;, was calculated over the diameter range 10 &amp;#8211; 500 nm.&lt;/p&gt;&lt;p&gt;As a result of enhanced sources, N&lt;sub&gt;tot&lt;/sub&gt; is generally higher during warmer seasons at all sites (in connection with atmospheric boundary layer dynamics for mountain sites). In addition, based on available MPSS data, the major contribution of Aitken mode particles (30-100 nm) to the total particle number concentration also appears as a common feature of all environments. In contrast, the observed levels of N&lt;sub&gt;tot&lt;/sub&gt;, between 10&lt;sup&gt;1&lt;/sup&gt; and 10&lt;sup&gt;4&lt;/sup&gt; cm&lt;sup&gt;-3&lt;/sup&gt;, and the magnitude of its seasonal cycle, exhibit, together with the variations of the PNSD, some distinctive behaviour for the different geographical categories and environmental footprint classes, with additional site-dependent characteristics. Among other factors (including the nature and proximity of the particles sources), the level of anthropogenic influence appears to strongly affect the observations.&lt;/p&gt;&lt;p&gt;This work will be completed in the near future with a trend analysis to document the temporal variability of the particle number concentration and PNSD.&lt;/p&gt;

scholarly journals Urban aerosol number size distributions

2003 ◽  
Vol 3 (5) ◽  
pp. 5139-5184 ◽  
Author(s):  
T. Hussein ◽  
A. Puustinen ◽  
P. P. Aalto ◽  
J. M. Mäkelä ◽  
K. Hämeri ◽  
...  
Keyword(s):  
Particle Number ◽  
Number Concentration ◽  
Building Construction ◽  
Traffic Density ◽  
Urban Aerosol ◽  
Size Distributions ◽  
Accumulation Mode ◽  
Total Particle Number ◽  
Total Particle ◽  
Aitken Mode

Abstract. Aerosol number size distributions were measured continuously in Helsinki, Finland from 5 May 1997 to 28 February 2003. The daily, monthly and annual patterns were investigated. The temporal variation of the particle number concentration was seen to follow the traffic density. The highest total particle number concentrations were usually observed during workdays; especially on Fridays, and the lower concentrations occurred during weekends; especially Sundays. Seasonally, the highest total number concentrations were usually observed during winter and spring and the lowest during June and July. More than 80\\% of the particle number size distributions were tri-modal: nucleation mode (Dp < 30 nm), Aitken mode (20–100 nm) and accumulation mode (Dp > 90 nm). Less than 20% of the particle number size distributions have either two modes or consisted of more than three modes. Two different measurement sites are used; in the first place (Siltavuori, 5 May 1997–5 March 2001), the overall means of the integrated particle number concentrations were 7100 cm−3, 6320 cm−3, and 960 cm−3, respectively, for nucleation, Aitken, and accumulation modes. In the second site (Kumpula, 6 March 2001–28 February 2003) they were 5670 cm−3, 4050 cm−3, and 900 cm−3. The total number concentration in nucleation and Aitken modes were usually significantly higher during weekdays than during weekends. The variations in accumulation mode were less pronounced. The smaller concentrations in Kumpula were mainly due to building construction and also slight overall decreasing trend during these years. During the site changing a period of simultaneous measurements over two weeks were performed showing nice correlation in both sites.

scholarly journals Analysis of number size distributions of tropical free tropospheric aerosol particles observed at Pico Espejo (4765 m a.s.l.), Venezuela

2011 ◽  
Vol 11 (7) ◽  
pp. 3319-3332 ◽  
Author(s):  
T. Schmeissner ◽  
R. Krejci ◽  
J. Ström ◽  
W. Birmili ◽  
A. Wiedensohler ◽  
...  
Keyword(s):  
Particle Number ◽  
Dry Season ◽  
Number Concentration ◽  
Aerosol Size Distribution ◽  
Particle Number Concentration ◽  
Size Distributions ◽  
Wet Season ◽  
Concentration Data ◽  
Diurnal Variability ◽  
Tropospheric Aerosol

Abstract. The first long-term measurements of aerosol number and size distributions in South-American tropical free troposphere (FT) were performed from March 2007 until March 2009. The measurements took place at the high altitude Atmospheric Research Station Alexander von Humboldt. The station is located on top of the Sierra Nevada mountain ridge at 4765 m a.s.l. nearby the city of Mérida, Venezuela. Aerosol size distribution and number concentration data was obtained with a custom-built Differential Mobility Particle Sizer (DMPS) system and a Condensational Particle Counter (CPC). The analysis of the annual and diurnal variability of the tropical FT aerosol focused mainly on possible links to the atmospheric general circulation in the tropics. Considerable annual and diurnal cycles of the particle number concentration were observed. Highest total particle number concentrations were measured during the dry season (January–March, 519 ± 613 cm−3), lowest during the wet season (July–September, 318 ± 194 cm−3). The more humid FT (relative humidity (RH) range 50–95 %) contained generally higher aerosol particle number concentrations (573 ± 768 cm−3 during dry season, 320 ± 195 cm−3 during wet season) than the dry FT (RH < 50 %, 454 ± 332 cm−3 during dry season, 275 ± 172 cm−3 during wet season), indicating the importance of convection for aerosol distributions in the tropical FT. The diurnal cycle in the variability of the particle number concentration was mainly driven by local orography.

scholarly journals A concept of an automated function control for ambient aerosol measurements using mobility particle size spectrometers

2014 ◽  
Vol 7 (4) ◽  
pp. 1065-1073 ◽  
Author(s):  
A. Schladitz ◽  
M. Merkel ◽  
S. Bastian ◽  
W. Birmili ◽  
K. Weinhold ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Number ◽  
Zero Point ◽  
Number Concentration ◽  
Quality Monitoring ◽  
Particle Number Concentration ◽  
Air Quality Monitoring ◽  
Condensation Particle Counter ◽  
Total Particle Number ◽  
Total Particle

Abstract. An automated function control unit was developed to regularly check the ambient particle number concentration derived from a mobility particle size spectrometer as well as its zero-point behaviour. The function control allows unattended quality assurance experiments at remote air quality monitoring or research stations under field conditions. The automated function control also has the advantage of being able to get a faster system stability response than the recommended on-site comparisons with reference instruments. The method is based on a comparison of the total particle number concentration measured by a mobility particle size spectrometer and a condensation particle counter while removing diffusive particles smaller than 20 nm in diameter. In practice, the small particles are removed by a set of diffusion screens, as traditionally used in a diffusion battery. Another feature of the automated function control is to check the zero-point behaviour of the ambient aerosol passing through a high-efficiency particulate air (HEPA) filter. The performance of the function control is illustrated with the aid of a 1-year data set recorded at Annaberg-Buchholz, a station in the Saxon air quality monitoring network. During the period of concern, the total particle number concentration derived from the mobility particle size spectrometer slightly overestimated the particle number concentration recorded by the condensation particle counter by 2 % (grand average). Based on our first year of experience with the function control, we developed tolerance criteria that allow a performance evaluation of a tested mobility particle size spectrometer with respect to the total particle number concentration. We conclude that the automated function control enhances the quality and reliability of unattended long-term particle number size distribution measurements. This will have beneficial effects for intercomparison studies involving different measurement sites, and help provide a higher data accuracy for cohort health and climate research studies.

Nanoparticle measurements used to detect an engine oil control ring failure

2009 ◽  
Vol 223 (8) ◽  
pp. 1071-1076 ◽  
Author(s):  
J Swanson ◽  
A Ragatz ◽  
W Watts ◽  
D Kittelson ◽  
R Winsor
Keyword(s):  
Particle Concentration ◽  
Particle Number ◽  
Number Concentration ◽  
Operating Conditions ◽  
Engine Oil ◽  
Exhaust Emission ◽  
Cyclic Variation ◽  
Particle Number Concentration ◽  
Total Particle Number ◽  
Total Particle

A cyclic variation in total particle number concentration was observed while making routine exhaust emission measurements. Many dilution and engine operating conditions were examined and, by sequentially shutting down individual cylinders, the problem was traced to cylinder 2. The engine was disassembled and piston 2's oil control ring was found to be fractured. Replacement of the ring eliminated the particle concentration fluctuation. This paper presents the results of experimental measurements made to determine the cause of the irregular emissions.

scholarly journals The variability of urban aerosol size distributions and optical properties in São Paulo – Brazil: new particle formation events occur at the site

2011 ◽  
Vol 11 (11) ◽  
pp. 30419-30455 ◽  
Author(s):  
J. Backman ◽  
L. V. Rizzo ◽  
J. Hakala ◽  
T. Nieminen ◽  
H. E. Manninen ◽  
...  
Keyword(s):  
Light Scattering ◽  
Growth Rates ◽  
Particle Number ◽  
Fossil Fuel ◽  
Sao Paulo ◽  
Number Concentration ◽  
Particle Number Concentration ◽  
São Paulo ◽  
Total Particle Number ◽  
Total Particle

Abstract. The quest to reduce the dependence on fossil fuel has increased the use of bio-ethanol as an additive to gasoline. The metropolitan area of São Paulo (population 20 million) is a unique laboratory to study the ambient aerosol population caused by the use of bio-fuels because 55% of the fuel used is ethanol. The use of ethanol as an additive to fossil fuel is known to increase aldehyde emissions and when photo chemically oxidized, result in smog. In order to characterize this smog problem total particle number concentration, particle number size distribution, light scattering and light absorption measurement equipment were deployed at the University of São Paulo campus area. Here we present the results from three months of measurements from 10 October 2010 to 10 January 2011. The median total particle number concentration for the sub-micron aerosol typically varies between 1×104–3×104 cm−3 frequently exceeding 5×104 cm−3 during the day. Median diurnal values for light absorption and light scattering vary between 12–33 Mm−1 and 21–64 Mm−1, respectively. The hourly median single-scattering albedo varied between 0.63 and 0.85 indicating a net warming effect on a regional scale. A total of ten new particle formation (NPF) events were observed. During these events, growth rates ranged between 9–25 nm h−1. On average, a calculated sulphuric acid vapour abundance of 2.6× 108 cm−3 would have explained the growth with a vapour production rate of 2.8×106 cm−3 s−1 to sustain it. The estimated sulphuric acid concentration, calculated from global irradiance and sulphur dioxide measurements, accounted for only a fraction of the vapour concentration needed to explain the observed growth rates. This indicates that also other condensable vapours participate in the growth process. During the events, the condensation sink was calculated to be 12× 10−3 s−1 on average.

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