scholarly journals A new aerosol collector for on-line analysis of particulate organic matter: the Aerosol Collection Module (ACM)

2010 ◽  
Vol 3 (2) ◽  
pp. 1361-1398 ◽  
Author(s):  
T. Hohaus ◽  
D. Trimborn ◽  
A. Kiendler-Scharr ◽  
I. Gensch ◽  
W. Laumer ◽  
...  
Keyword(s):  
Organic Matter ◽  
Gas Phase ◽  
Atmospheric Aerosol ◽  
Phase Transfer ◽  
Collection Efficiency ◽  
Aerosol Particles ◽  
High Vacuum ◽  
Chemical Characterization ◽  
Organic Aerosol ◽  
Atmospheric Aerosol Particles

Abstract. In many environments organic matter significantly contributes to the composition of atmospheric aerosol particles influencing its properties. Detailed chemical characterization of ambient aerosols is critical in order to understand the formation process, composition, and properties of aerosols in the atmosphere. However, current analytical methods are far from full speciation of organic aerosols and often require long sampling times. Offline methods are also subjected to artifacts during aerosol collection and storage. In the present work a new technique for quasi-online compound specific measurements of organic aerosol particles was developed. The Aerosol Collection Module (ACM) is designed to sample, collect and transfer gasified atmospheric aerosol particles. The system focuses particles into a beam which is directed to a cooled sampling surface. The sampling takes places in a high vacuum environment where the gas phase from the sample volume is removed. After collection the particle sample is evaporated from the collection surface through heating and transferred to a detector. For laboratory characterization the ACM was interfaced with a Gas Chromatograph Mass Spectrometer system (GC-MS). The particle collection efficiency, gas phase transfer efficiency, and linearity of the ACM-GC-MS were determined using laboratory generated octadecane aerosols. The ACM-GC-MS is linear over the investigated mass range of 10 to 100 ng and a recovery rate of 100% was found for octadecane particles. The ACM-GC-MS was applied to investigate secondary organic aerosol (SOA) formed from β-pinene oxidation. Nopinone, myrtanal, myrtenol, 1-hydroxynopinone, 3-oxonopinone, 3,7-dihydroxynopinone, and bicyclo[3,1,1]hept-3-ene-2-one were found as products in the SOA. The ACM results are compared to quartz filter samples taken in parallel to the ACM measurements. First measurements of ambient atmospheric aerosols are presented.

scholarly journals A new aerosol collector for quasi on-line analysis of particulate organic matter: the Aerosol Collection Module (ACM) and first applications with a GC/MS-FID

2010 ◽  
Vol 3 (5) ◽  
pp. 1423-1436 ◽  
Author(s):  
T. Hohaus ◽  
D. Trimborn ◽  
A. Kiendler-Scharr ◽  
I. Gensch ◽  
W. Laumer ◽  
...  
Keyword(s):  
Organic Matter ◽  
Gas Phase ◽  
Phase Transfer ◽  
Collection Efficiency ◽  
Aerosol Particles ◽  
High Vacuum ◽  
Chemical Characterization ◽  
Organic Aerosol ◽  
Ambient Aerosols ◽  
On Line

Abstract. In many environments organic matter significantly contributes to the composition of atmospheric aerosol particles influencing its properties. Detailed chemical characterization of ambient aerosols is critical in order to understand the formation process, composition, and properties of aerosols and facilitates source identification and relative contributions from different types of sources to ambient aerosols in the atmosphere. However, current analytical methods are far from full speciation of organic aerosols and often require sampling times of up to one week. Offline methods are also subjected to artifacts during aerosol collection and storage. In the present work a new technique for quasi on-line compound specific measurements of organic aerosol particles was developed. The Aerosol Collection Module (ACM) focuses particles into a beam which is directed to a cooled sampling surface. The sampling takes place in a high vacuum environment where the gas phase from the sample volume is removed. After collection is completed volatile and semi-volatile compounds are evaporated from the collection surface through heating and transferred to a detector. For laboratory characterization the ACM was interfaced with a Gas Chromatograph Mass Spectrometer, Flame Ionization Detector system (GC/MS-FID), abbreviated as ACM GC-MS. The particle collection efficiency, gas phase transfer efficiency, and linearity of the ACM GC-MS were determined using laboratory generated octadecane aerosols. The ACM GC-MS is linear over the investigated mass range of 10 to 100 ng and a recovery rate of 100% was found for octadecane particles. The ACM GC-MS was applied to investigate secondary organic aerosol (SOA) formed from β-pinene oxidation. Nopinone, myrtanal, myrtenol, 1-hydroxynopinone, 3-oxonopinone, 3,7-dihydroxynopinone, and bicyclo[3,1,1]hept-3-ene-2-one were found as products in the SOA. The ACM GC-MS results are compared to quartz filter samples taken in parallel to the ACM GC-MS measurements. First measurements of ambient atmospheric aerosols are presented.

A condensation-growth and impaction method for rapid off-line chemical-characterization of organic submicrometer atmospheric aerosol particles

2003 ◽  
Vol 34 (2) ◽  
pp. 225-242 ◽  
Author(s):  
Berko Sierau ◽  
Frank Stratmann ◽  
Matthias Pelzing ◽  
Christian Neusüß ◽  
Diana Hofmann ◽  
...  
Keyword(s):  
Atmospheric Aerosol ◽  
Aerosol Particles ◽  
Chemical Characterization ◽  
Atmospheric Aerosol Particles ◽  
Condensation Growth

scholarly journals Review and uncertainty assessment of size-resolved scavenging coefficient formulations for snow scavenging of atmospheric aerosols

2013 ◽  
Vol 13 (6) ◽  
pp. 14823-14869 ◽  
Author(s):  
L. Zhang ◽  
X. Wang ◽  
M. D. Moran ◽  
J. Feng
Keyword(s):  
Atmospheric Aerosols ◽  
Atmospheric Aerosol ◽  
Collection Efficiency ◽  
Aerosol Particles ◽  
Field Measurements ◽  
Cross Sectional ◽  
Atmospheric Aerosol Particles ◽  
Order Of Magnitude ◽  
Snow Particle ◽  
Scavenging Coefficient

Abstract. Theoretical parameterizations for the size-resolved scavenging coefficient for atmospheric aerosol particles scavenged by snow (Λsnow) need assumptions regarding (i) snow particle–aerosol particle collection efficiency E, (ii) snow particle size distribution N(Dp), (iii) snow particle terminal velocity VD, and (iv) snow particle cross-sectional area A. Existing formulas for these parameters are reviewed in the present study and uncertainties in Λsnow caused by various combinations of these parameters are assessed. Different formulations of E can cause uncertainties in Λsnow of more than one order of magnitude for all aerosol sizes for typical snowfall intensities. E is the largest source of uncertainty among all the input parameters, similar to rain scavenging of atmospheric aerosols (Λrain) as was found in a previous study by Wang et al. (2010). However, other parameters can also cause significant uncertainties in Λsnow, and the uncertainties from these parameters are much larger than for Λrain. Specifically, different N(Dp) formulations can cause one-order-of-magnitude uncertainties in Λsnow for all aerosol sizes, as is also the case for a combination of uncertainties from both VD and A. In comparison, uncertainties in Λrain from N(Dp) are smaller than a factor of 5 and those from VD are smaller than a factor of 2. Λsnow estimated from one empirical formula generated from field measurements falls in the upper range of, or is slightly higher than, theoretically estimated values. The predicted aerosol concentrations obtained using different Λsnow formulas can differ by a factor of two for just a one-centimeter snowfall (liquid water equivalent of approximately 1 mm). It is likely that, for typical rain and snow event the removal of atmospheric aerosol particles by snow is more effective than removal by rain for equivalent precipitation amounts, although a firm conclusion requires much more evidence.

scholarly journals Review and uncertainty assessment of size-resolved scavenging coefficient formulations for below-cloud snow scavenging of atmospheric aerosols

2013 ◽  
Vol 13 (19) ◽  
pp. 10005-10025 ◽  
Author(s):  
L. Zhang ◽  
X. Wang ◽  
M. D. Moran ◽  
J. Feng
Keyword(s):  
Atmospheric Aerosols ◽  
Atmospheric Aerosol ◽  
Collection Efficiency ◽  
Aerosol Particles ◽  
Empirical Formulas ◽  
Cross Sectional ◽  
Atmospheric Aerosol Particles ◽  
Order Of Magnitude ◽  
Snow Particle ◽  
Scavenging Coefficient

Abstract. Theoretical parameterizations for the size-resolved scavenging coefficient for atmospheric aerosol particles scavenged by snow (Λsnow) need assumptions regarding (i) snow particle–aerosol particle collection efficiency E, (ii) snow-particle size distribution N(Dp), (iii) snow-particle terminal velocity VD, and (iv) snow-particle cross-sectional area A. Existing formulas for these parameters are reviewed in the present study, and uncertainties in Λsnow caused by various combinations of these parameters are assessed. Different formulations of E can cause uncertainties in Λsnow of more than one order of magnitude for all aerosol sizes for typical snowfall intensities. E is the largest source of uncertainty among all the input parameters, similar to rain scavenging of atmospheric aerosols (Λrain) as was found in a previous study by Wang et al. (2010). However, other parameters can also cause significant uncertainties in Λsnow, and the uncertainties from these parameters are much larger than for Λrain. Specifically, different N(Dp) formulations can cause one-order-of-magnitude uncertainties in Λsnow for all aerosol sizes, as is also the case for a combination of uncertainties from both VD and A. Assumptions about dominant snow-particle shape (and thus different VD and A) will cause an uncertainty of up to one order of magnitude in the calculated scavenging coefficient. In comparison, uncertainties in Λrain from N(Dp) are smaller than a factor of 5, and those from VD are smaller than a factor of 2. As expected, Λsnow estimated from empirical formulas generated from field measurements falls in the upper range of, or is higher than, the theoretically estimated values, which can be explained by additional processes/mechanisms that influence field-derived Λsnow but that are not considered in the theoretical Λsnow formulas. Predicted aerosol concentrations obtained by using upper range vs. lower range of Λsnow values (a difference of around two orders of magnitude in Λsnow) can differ by a factor of 2 for just a one-centimetre snowfall (liquid water equivalent of approximately 1 mm). Based on the median and upper range of theoretically generated Λsnow and Λsnow values, it is likely that, for typical rain and snow events, the removal of atmospheric aerosol particles by snow is more effective than removal by rain for equivalent precipitation amounts, although a firm conclusion requires much more evidence.

scholarly journals Bounce behavior of freshly nucleated biogenic secondary organic aerosol particles

2011 ◽  
Vol 11 (3) ◽  
pp. 9313-9334
Author(s):  
A. Virtanen ◽  
J. Kannosto ◽  
J. Joutsensaari ◽  
E. Saukko ◽  
H. Kuuluvainen ◽  
...  
Keyword(s):  
Atmospheric Aerosol ◽  
Phase State ◽  
Size Range ◽  
Secondary Organic Aerosol ◽  
Solid Phase ◽  
Particle Density ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Atmospheric Aerosol Particles ◽  
Particle Bounce

Abstract. The assessment of the climatic impacts and adverse health effects of atmospheric aerosol particles requires detailed information on particle properties. However, very limited information is available on the morphology and phase state of secondary organic aerosol (SOA) particles. The physical state of particles greatly affects particulate-phase chemical reactions, and thus the growth rates of newly formed atmospheric aerosol particles. Thus verifying the physical phase state of SOA particles gives new and important insight into their formation, subsequent growth, and consequently potential atmospheric impacts. According to our recent study, biogenic SOA particles produced in laboratory chambers from the oxidation of real plant emissions as well as in ambient boreal forest atmospheres can exist in a solid phase in size range >30 nm. In this paper, we extend previously published results to diameters in the range of 17–30 nm. The physical phase of the particles is studied by investigating particle bounce properties utilizing electrical low pressure impactor (ELPI). We also investigate the effect of estimates of particle density on the interpretation of our bounce observations. According to the results presented in this paper, particle bounce clearly decreases with decreasing particle size in sub 30 nm size range. The decreasing bounce can be caused by the differences in composition and phase of large (diameters greater than 30 nm) and smaller (diameters between 17 and 30 nm) particles.

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