scholarly journals Chemical characterization of the inorganic fraction of aerosols and mechanisms of the neutralization of atmospheric acidity in Athens, Greece

2007 ◽  
Vol 7 (11) ◽  
pp. 3015-3033 ◽  
Author(s):  
E. T. Karageorgos ◽  
S. Rapsomanikis
Keyword(s):  
Mass Concentration ◽  
Fine Fraction ◽  
Ambient Air ◽  
Coarse Fraction ◽  
Particle Mass ◽  
Coarse Particle ◽  
Breathing Zone ◽  
Neutralizing Agent ◽  
Pm10 Mass ◽  
Mass Concentrations

Abstract. The PM10 mass concentration levels and inorganic chemical composition were determined on 12-h resolution sampling during August 2003 and March 2004, in the centre of Athens, Greece. The August 2003 campaign mean PM10 mass concentration, obtained by Beta Attenuation at 5 m above ground in Athinas Street, was 56 μg m−3 while the corresponding value for March 2004 was 92 μg m−3. In both campaigns the E.U. imposed daily limit of 50 μg m−3 was exceeded on several days. During the March campaign, in Athinas Street, additionally obtained DSFU-PM10 (PM10-2.5+PM2.5) gravimetric mass concentrations (mean: 121 μg m−3) in the "breathing zone", at 1.5 m above ground were significantly higher compared to the respective mean PM10 mass concentrations obtained by the same method at 25 m above ground, in a second site (AEDA; mean: 86 μg m−3) also in the centre of the city. The above findings suggest that, for a realistic estimation of the exposure of citizens to particulate matter, PM10 sampling in the "breathing zone" (1.5–3 m above ground) is necessary. Such data are presented for the first time for the centre of Athens. In both campaigns, calcium was found to be the predominant component of the coarse fraction while crust-related aluminosilicates and iron were the other major components. The above elements constitute the most important components of the fine fraction, together with the predominant sulphur. All toxic metals were found in concentrations below the established air quality limits, and most of them in lower concentrations compared to older studies. Lead in particular, appeared mostly in the fine fraction and in very low concentrations compared to studies dating more than a decade back. The predominant ions of the coarse fraction have been found to be Ca2+, NO3−, Na+ and Cl−, while SO42−, Ca2+ and NH4+ were the major ionic components of the fine fraction. In the fine particles, a low molar ratio of NH4+/SO42− indicated an ammonium-poor ambient air, and together with inter-ionic correlations suggested that atmospheric ammonia is the major neutralizing agent of sulfate, while being insufficient to neutralize it to full extend. The formation of NH4NO3 is therefore not favored and additional contribution to the neutralization of acidity has been shown to be provided by Ca2+ and Mg2+. In the coarse particle fraction, the predominantly abundant Ca2+ has been found to correlate well with NO3− and SO42−, indicating its role as important neutralizing agent in this particle size range. The proximity of the location under study to the sea explains the important concentrations of salts with marine origin like NaCl and MgCl2 that were found in the coarse fraction, while chloride depletion in the gaseous phase was found to be limited to the fine particulate fraction. Total analyzed inorganic mass (elemental+ionic) was found to be ranging between approximately 25–33% of the total coarse particle mass and 35–42% of the total fine particle mass.

scholarly journals Chemical characterization of the inorganic fraction of aerosols and mechanisms of the neutralization of atmospheric acidity in Athens, Greece

2006 ◽  
Vol 6 (6) ◽  
pp. 12389-12431
Author(s):  
E. T. Karageorgos ◽  
S. Rapsomanikis ◽  
P. Wåhlin
Keyword(s):  
Mass Concentration ◽  
Major Ions ◽  
Fine Fraction ◽  
Ambient Air ◽  
Coarse Fraction ◽  
Particle Mass ◽  
Molar Ratio ◽  
Breathing Zone ◽  
Predominant Component ◽  
Neutralizing Agent

Abstract. Mass concentration levels and the inorganic chemical composition of PM10 (two fractions; PM10−2.5 and PM2.5) were determined during August 2003 and March 2004, in the centre of Athens, Greece. August 2003 monthly mean PM10 mass concentration, at 5 m above ground, was 56 μg/m3 and the EU imposed daily limit of 50 μg/m3 was exceeded on 16 occasions. The corresponding monthly mean for March 2004 was 92 μg/m3 and the aforementioned daily limit was exceeded on 23 occasions. The PM10 (PM10−2.5+PM2.5) mass concentrations at 1.5 m above ground were found to be approximately 20% higher compared to the respective PM10 measured at 5 m. Consequently, for a realistic estimation of the exposure of citizens to particulate matter, PM10 sampling at a height of 1.5–3 m above ground, in the "breathing zone" is necessary. Such data are presented for the first time for the centre of Athens. In both campaigns, calcium was found to be the predominant component of the coarse fraction while crust-related aluminosilicates and iron were found to be the other major components of the same fraction. The above elements constitute the most important components of the fine fraction, together with the predominant sulphur. Toxic metals were found to be below the air quality limits and in lower concentrations compared to older studies, with the exception of Cu and V for which some increase was observed. Pb, in particular, appeared mostly in the fine fraction and in very low concentrations compared to studies dating more than a decade back. The major ions of the coarse fraction have been found to be Ca2+, NO3− and Cl−, while SO4−2, Ca2+ and NH4+ were the major ionic components of the fine fraction. The low molar ratio of NH4+/SO4−2 indicated an ammonium-poor ambient air, where atmospheric ammonia is not sufficient to neutralize all acidity and the formation of NH4NO3 does not occur to a significant extend. Calcium predominated the coarse fraction and its good correlations with NO3− and SO4−2 indicated its role as an important neutralizing agent of atmospheric acidity in this particle size range. In the fine fraction, both Ca2+ and NH4+ participate in the neutralizing processes with NH4+ being the major neutralizing agent of SO4−2. Chloride depletion from NaCl or MgCl2 was not found to occur to a significant extend. Total analyzed inorganic mass (elemental+ionic) was found to be ranging between approximately 25–33% of the total coarse particle mass and 35–42% of the total fine particle mass.

scholarly journals Sources and mixing state of size-resolved elemental carbon particles in a European megacity: Paris

2012 ◽  
Vol 12 (4) ◽  
pp. 1681-1700 ◽  
Author(s):  
R. M. Healy ◽  
J. Sciare ◽  
L. Poulain ◽  
K. Kamili ◽  
M. Merkel ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Biomass Burning ◽  
Single Particle ◽  
Mass Concentration ◽  
Elemental Carbon ◽  
Fossil Fuel ◽  
Time Of Flight ◽  
Particle Mass ◽  
Mass Size ◽  
Mass Concentrations

Abstract. An Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS) was deployed to investigate the size-resolved chemical composition of single particles at an urban background site in Paris, France, as part of the MEGAPOLI winter campaign in January/February 2010. ATOFMS particle counts were scaled to match coincident Twin Differential Mobility Particle Sizer (TDMPS) data in order to generate hourly size-resolved mass concentrations for the single particle classes observed. The total scaled ATOFMS particle mass concentration in the size range 150–1067 nm was found to agree very well with the sum of concurrent High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and Multi-Angle Absorption Photometer (MAAP) mass concentration measurements of organic carbon (OC), inorganic ions and black carbon (BC) (R2 = 0.91). Clustering analysis of the ATOFMS single particle mass spectra allowed the separation of elemental carbon (EC) particles into four classes: (i) EC attributed to biomass burning (ECbiomass), (ii) EC attributed to traffic (ECtraffic), (iii) EC internally mixed with OC and ammonium sulfate (ECOCSOx), and (iv) EC internally mixed with OC and ammonium nitrate (ECOCNOx). Average hourly mass concentrations for EC-containing particles detected by the ATOFMS were found to agree reasonably well with semi-continuous quantitative thermal/optical EC and optical BC measurements (r2 = 0.61 and 0.65–0.68 respectively, n = 552). The EC particle mass assigned to fossil fuel and biomass burning sources also agreed reasonably well with BC mass fractions assigned to the same sources using seven-wavelength aethalometer data (r2 = 0.60 and 0.48, respectively, n = 568). Agreement between the ATOFMS and other instrumentation improved noticeably when a period influenced by significantly aged, internally mixed EC particles was removed from the intercomparison. 88% and 12% of EC particle mass was apportioned to fossil fuel and biomass burning respectively using the ATOFMS data compared with 85% and 15% respectively for BC estimated from the aethalometer model. On average, the mass size distribution for EC particles is bimodal; the smaller mode is attributed to locally emitted, mostly externally mixed EC particles, while the larger mode is dominated by aged, internally mixed ECOCNOx particles associated with continental transport events. Periods of continental influence were identified using the Lagrangian Particle Dispersion Model (LPDM) "FLEXPART". A consistent minimum between the two EC mass size modes was observed at approximately 400 nm for the measurement period. EC particles below this size are attributed to local emissions using chemical mixing state information and contribute 79% of the scaled ATOFMS EC particle mass, while particles above this size are attributed to continental transport events and contribute 21% of the EC particle mass. These results clearly demonstrate the potential benefit of monitoring size-resolved mass concentrations for the separation of local and continental EC emissions. Knowledge of the relative input of these emissions is essential for assessing the effectiveness of local abatement strategies.

scholarly journals Evaluation of a low-cost optical particle counter (Alphasense OPC-N2) for ambient air monitoring

2018 ◽  
Vol 11 (2) ◽  
pp. 709-720 ◽  
Author(s):  
Leigh R. Crilley ◽  
Marvin Shaw ◽  
Ryan Pound ◽  
Louisa J. Kramer ◽  
Robin Price ◽  
...  
Keyword(s):  
Low Cost ◽  
Ambient Air ◽  
Particle Mass ◽  
Particle Counter ◽  
Optical Particle Counter ◽  
Attractive Option ◽  
Kohler Theory ◽  
Pm2.5 And Pm10 ◽  
The Uk ◽  
Mass Concentrations

Abstract. A fast-growing area of research is the development of low-cost sensors for measuring air pollutants. The affordability and size of low-cost particle sensors makes them an attractive option for use in experiments requiring a number of instruments such as high-density spatial mapping. However, for these low-cost sensors to be useful for these types of studies their accuracy and precision need to be quantified. We evaluated the Alphasense OPC-N2, a promising low-cost miniature optical particle counter, for monitoring ambient airborne particles at typical urban background sites in the UK. The precision of the OPC-N2 was assessed by co-locating 14 instruments at a site to investigate the variation in measured concentrations. Comparison to two different reference optical particle counters as well as a TEOM-FDMS enabled the accuracy of the OPC-N2 to be evaluated. Comparison of the OPC-N2 to the reference optical instruments shows some limitations for measuring mass concentrations of PM1, PM2.5 and PM10. The OPC-N2 demonstrated a significant positive artefact in measured particle mass during times of high ambient RH (> 85 %) and a calibration factor was developed based upon κ-Köhler theory, using average bulk particle aerosol hygroscopicity. Application of this RH correction factor resulted in the OPC-N2 measurements being within 33 % of the TEOM-FDMS, comparable to the agreement between a reference optical particle counter and the TEOM-FDMS (20 %). Inter-unit precision for the 14 OPC-N2 sensors of 22 ± 13 % for PM10 mass concentrations was observed. Overall, the OPC-N2 was found to accurately measure ambient airborne particle mass concentration provided they are (i) correctly calibrated and (ii) corrected for ambient RH. The level of precision demonstrated between multiple OPC-N2s suggests that they would be suitable devices for applications where the spatial variability in particle concentration was to be determined.

scholarly journals Spatiotemporal and Source Analysis of Ultrafine Particulates (PM1) over Bengaluru, Karnataka, India

2020 ◽  
Author(s):  
Manjunatha A S ◽  
Ganesh K E
Keyword(s):  
Electron Microscope ◽  
Air Quality ◽  
Scanning Electron Microscope ◽  
Elemental Composition ◽  
Mass Concentration ◽  
Ambient Air ◽  
Source Analysis ◽  
Standard Limit ◽  
Scanning Electron ◽  
Mass Concentrations

Abstract Measurement and analysis of Particulate Matter (PM1) of aerodynamic diameter less than 1µm (PM1) has been carried out using indigenously built air sampler APM 577 from IIT-K for the period July 2018 - July 2019. Bengaluru being one of the megacities of India requires constant follow up of air quality. Following locations of Bengaluru city have been selected for the study: Basavanagudi (BAS), Domlur (DOM), Hosur road (HOS) and DC Halli (DCH). The mass concentrations of collected PM1 samples have been observed to vary from 20.16 to 68.64 µg m-3 during the study period. The highest mass concentration of 68.64 µg m-3 was observed for the location BAS and the lowest mass concentration of 20.16 µg m-3 was observed for the location DOM. The seasonal average mass concentration of PM1 around Bengaluru for winter, summer, monsoon & post monsoon season during the entire study period is observed to be 47.60, 40.24, 30.85 and 38.76 µg m-3 respectively. The average 24 h mass concentrations of PM1 in winter season that is in December month at BAS location is found to be higher than National Ambient Air Quality Standard limit of 60 µg m-3 for PM2.5 however in January and February months mass concentration is found to be less than the standard limit. The Scanning Electron Microscope-Energy Dispersive Analysis X-ray techniques were used to understand the morphology and elemental composition of PM1. Scanning electron microscope images confirms the presence of particulates both from anthropogenic (primary) and natural (secondary) activities. Also, some of the collected samples showed the presence of microorganisms and biological particles such as Bacillus. Elemental composition analysis showed the presence of non-metals such as Carbon, Oxygen, Nitrogen, Sulphur and traces of metals such as Sodium, Aluminium, Calcium and Potassium. A detailed study along with the possible conclusion is the subject matter of this paper.

Estimation of particle mass concentration in ambient air using a particle counter

2008 ◽  
Vol 42 (36) ◽  
pp. 8543-8548 ◽  
Author(s):  
A TITTARELLI ◽  
A BORGINI ◽  
M BERTOLDI ◽  
E DESAEGER ◽  
A RUPRECHT ◽  
...  
Keyword(s):  
Mass Concentration ◽  
Ambient Air ◽  
Particle Mass ◽  
Particle Counter ◽  
Particle Mass Concentration

scholarly journals Multi-year ACSM measurements at the central European research station Melpitz (Germany) – Part 1: Instrument robustness, quality assurance, and impact of upper size cutoff diameter

2020 ◽  
Vol 13 (9) ◽  
pp. 4973-4994
Author(s):  
Laurent Poulain ◽  
Gerald Spindler ◽  
Achim Grüner ◽  
Thomas Tuch ◽  
Bastian Stieger ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Seasonal Variability ◽  
Mass Concentration ◽  
Particle Mass ◽  
Fundamental Aspect ◽  
Research Station ◽  
Organic Mass ◽  
Mass Closure ◽  
Mass Concentrations

Abstract. The aerosol chemical speciation monitor (ACSM) is nowadays widely used to identify and quantify the main components of fine particles in ambient air. As such, its deployment at observatory platforms is fully incorporated within the European Aerosol, Clouds and Trace Gases Research Infrastructure (ACTRIS). Regular intercomparisons are organized at the Aerosol Chemical Monitoring Calibration Center (ACMCC; part of the European Center for Aerosol Calibration, Paris, France) to ensure the consistency of the dataset, as well as instrumental performance and variability. However, in situ quality assurance remains a fundamental aspect of the instrument's stability. Here, we present and discuss the main outputs of long-term quality assurance efforts achieved for ACSM measurements at the research station Melpitz (Germany) since 2012 onwards. In order to validate the ACSM measurements over the years and to characterize seasonal variations, nitrate, sulfate, ammonium, organic, and particle mass concentrations were systematically compared against the collocated measurements of daily offline high-volume PM1 and PM2.5 filter samples and particle number size distribution (PNSD) measurements. Mass closure analysis was made by comparing the total particle mass (PM) concentration obtained by adding the mass concentration of equivalent black carbon (eBC) from the multi-angle absorption photometer (MAAP) to the ACSM chemical composition, to that of PM1 and PM2.5 during filter weighing, as well as to the derived mass concentration of PNSD. A combination of PM1 and PM2.5 filter samples helped identifying the critical importance of the upper size cutoff of the ACSM during such exercises. The ACSM–MAAP-derived mass concentrations systematically deviated from the PM1 mass when the mass concentration of the latter represented less than 60 % of PM2.5, which was linked to the transmission efficiency of the aerodynamic lenses of the ACSM. The best correlations are obtained for sulfate (slope =0.96; R2=0.77) and total PM (slope =1.02; R2=0.90). Although, sulfate did not exhibit a seasonal dependency, total PM mass concentration revealed a small seasonal variability linked to the increase in non-water-soluble fractions. The nitrate suffers from a loss of ammonium nitrate during filter collection, and the contribution of organo-nitrate compounds to the ACSM nitrate signal make it difficult to directly compare the two methods. The contribution of m∕z 44 (f44) to the total organic mass concentration was used to convert the ACSM organic mass (OM) to organic carbon (OC) by using a similar approach as for the aerosol mass spectrometer (AMS). The resulting estimated OCACSM was compared with the measured OCPM1 (slope =0.74; R2=0.77), indicating that the f44 signal was relatively free of interferences during this period. The PM2.5 filter samples use for the ACSM data quality might suffer from a systematic bias due to a size truncation effect as well as to the presence of chemical species that cannot be detected by the ACSM in coarse mode (e.g., sodium nitrate and sodium sulfate). This may lead to a systematic underestimation of the ACSM particle mass concentration and/or a positive artifact that artificially decreases the discrepancies between the two methods. Consequently, ACSM data validation using PM2.5 filters has to be interpreted with extreme care. The particle mass closure with the PNSD was satisfying (slope =0.77; R2=0.90 over the entire period), with a slight overestimation of the mobility particle size spectrometer (MPSS)-derived mass concentration in winter. This seasonal variability was related to a change on the PNSD and a larger contribution of the supermicrometer particles in winter. This long-term analysis between the ACSM and other collocated instruments confirms the robustness of the ACSM and its suitability for long-term measurements. Particle mass closure with the PNSD is strongly recommended to ensure the stability of the ACSM. A near-real-time mass closure procedure within the entire ACTRIS–ACSM network certainly represents an optimal quality control and assurance of both warranting the quality assurance of the ACSM measurements as well as identifying cross-instrumental biases.

The impact of wind on particle mass concentrations in four european urban areas

2013 ◽  
Vol 15 (2) ◽  
pp. 188-194 ◽  
Keyword(s):  
Urban Areas ◽  
Fine Particles ◽  
Multivariate Regression Analysis ◽  
Positive Influence ◽  
Particle Mass ◽  
Coarse Particle ◽  
Receptor Sites ◽  
Strong Winds ◽  
The Impact ◽  
Mass Concentrations

The impacts of wind conditions to fine and coarse particle mass concentrations at four European urban centers, by multivariate regression analysis of particle measurements against categorized wind (direction and speed) conditions were estimated. Statistically significant associations (both positive and negative) were observed for all urban areas. Both fine and coarse particle mass concentrations were decreased for moderate and strong winds (speed > 2.2 m s-1) in Athens and Helsinki. Weak winds had a positive influence on particle mass, accounting for up to 40% of fine particles in Athens. For the three coastal urban areas (Amsterdam, Athens and Helsinki), positive correlations were observed for sectors encompassing ports and areas with intense marine traffic. For Birmingham, the association of both particle fractions with the eastern sector indicated the influence of emissions from central UK and continental Europe. The method described here may be used to screen the orientation of sources near receptor sites.

Fine and coarse particle mass concentrations and emission rates in the workplace of a detergent industry

2013 ◽  
Vol 23 (6) ◽  
pp. 881-889 ◽  
Author(s):  
Thodoros Glytsos ◽  
Jakub Ondráček ◽  
Lucie Džumbová ◽  
Kostas Eleftheriadis ◽  
Mihalis Lazaridis
Keyword(s):  
Particle Mass ◽  
Detergent Industry ◽  
Coarse Particle ◽  
Emission Rates ◽  
Mass Concentrations
Sign in / Sign up

Export Citation Format

Share Document