Aerosol Instrumentation

2014 ◽  
pp. 61-87
Author(s):  
Da-Ren Chen ◽  
David Y. H. Pui
2012 ◽  
Vol 12 (18) ◽  
pp. 8439-8458 ◽  
Author(s):  
M. M. Coggon ◽  
A. Sorooshian ◽  
Z. Wang ◽  
A. R. Metcalf ◽  
A. A. Frossard ◽  
...  

Abstract. We report properties of marine aerosol and clouds measured in the shipping lanes between Monterey Bay and San Francisco off the coast of Central California. Using a suite of aerosol instrumentation onboard the CIRPAS Twin Otter aircraft, these measurements represent a unique set of data contrasting the properties of clean and ship-impacted marine air masses in dry aerosol and cloud droplet residuals. Below-cloud aerosol exhibited average mass and number concentrations of 2 μg m−3 and 510 cm−3, respectively, which are consistent with previous studies performed off the coast of California. Enhancements in vanadium and cloud droplet number concentrations are observed concurrently with a decrease in cloud water pH, suggesting that periods of high aerosol loading are primarily linked to increased ship influence. Mass spectra from a compact time-of-flight Aerodyne aerosol mass spectrometer reveal an enhancement in the fraction of organic at m/z 42 (f42) and 99 (f99) in ship-impacted clouds. These ions are well correlated to each other (R2>0.64) both in and out of cloud and constitute 14% (f44) and 3% (f99) of organic mass during periods of enhanced sulfate. High-resolution mass spectral analysis of these masses from ship measurements suggests that the ions responsible for this variation were oxidized, possibly due to cloud processing. We propose that the organic fractions of these ions be used as a metric for determining the extent to which cloud-processed ship emissions impact the marine atmosphere where (f42 > 0.15; f99 > 0.04) would imply heavy influence from shipping emissions, (0.05 < f42 < 0.15; 0.01 < f99 < 0.04) would imply moderate, but persistent, influences from ships, and (f42 < 0.05; f99 < 0.01) would imply clean, non-ship-influenced air.


1984 ◽  
Vol 15 (3) ◽  
pp. 347-349 ◽  
Author(s):  
L. Strom ◽  
J.M. Mäkynen ◽  
W. Piispanen

2016 ◽  
Vol 50 (12) ◽  
pp. 1375-1384 ◽  
Author(s):  
Christof Asbach ◽  
Heinz Kaminski ◽  
Yvonne Lamboy ◽  
Ute Schneiderwind ◽  
Martin Fierz ◽  
...  

2012 ◽  
Vol 12 (6) ◽  
pp. 14393-14445 ◽  
Author(s):  
M. M. Coggon ◽  
A. Sorooshian ◽  
Z. Wang ◽  
A. R. Metcalf ◽  
A. A. Frossard ◽  
...  

Abstract. We report properties of marine aerosol and clouds measured in the shipping lanes between Monterey Bay and San Francisco off the coast of Central California. Using a suite of aerosol instrumentation onboard the CIRPAS Twin Otter aircraft, these measurements represent a unique set of data contrasting the properties of clean and ship-impacted marine air masses in dry aerosol and cloud droplet residuals. Average mass and number concentrations of below-cloud aerosol of 2 μg m−3 and 510 cm−3 are consistent with previous studies performed off the coast of California. Enhancement of vanadium and cloud droplet number concentration observed concurrently with a decrease in cloud water pH suggests that periods of high aerosol loading are primarily linked to increased ship influence. Mass spectra from a compact time-of-flight Aerodyne aerosol mass spectrometer reveal an enhancement in the fraction of organic at m/z 42 (f42) and 99 (f99) in ship-impacted clouds. These ions are well correlated to each other (R2 > 0.64) both in and out of cloud and dominate organic mass during periods of enhanced sulfate. High-resolution mass spectral analysis of these masses from ship measurements suggests that the ions responsible for this variation were oxidized, possibly due to cloud processing. We propose that the organic fractions of these ions be used as a metric for determining the extent to which ships impact the marine atmosphere where (f42 > 0.15; f99 > 0.04) would imply heavy influence from shipping emissions, (0.05 < f42 < 0.15; 0.01 < f99 < 0.04) would imply moderate, but persistent, influences from ships, and (f42 < 0.05; f99 < 0.01) would imply clean, non-ship-influenced air.


2005 ◽  
Vol 36 (8) ◽  
pp. 1006-1022 ◽  
Author(s):  
Michael D. Geller ◽  
Subhasis Biswas ◽  
Philip M. Fine ◽  
Constantinos Sioutas

2004 ◽  
Vol 19 (5) ◽  
pp. 1544-1550 ◽  
Author(s):  
H. Keskinen ◽  
J.M. Mäkelä ◽  
M. Vippola ◽  
M. Nurminen ◽  
J. Liimatainen ◽  
...  

Ag–Pd alloy nanoparticles have been generated from silver and palladium nitrate precursors using a high temperature aerosol method, the liquid flame spray (LFS) process. In the LFS process, a spray aerosol of precursor liquid is introduced into a high-temperature H2–O2 flame. The primary micron-sized spray droplets evaporatein the flame, and the final particulate product is a result of the nucleation of the pure metal vapors shortly after the flame. In the study, three Ag–Pd molar ratios—10:90, 50:50, and 90:10—were used in the precursor. As a result of the synthesis, metalalloy nanoparticles with practically the same concentration ratios, correspondingly, were produced with the method. In the experiments, metal mass flow rates of 0.01–0.8 g/min were covered. The size of the particles was determined to be in the rangeof 10–50 nm by aerosol instrumentation. The particles were spherical and slightly agglomerated. It was concluded that the particle size can be controlled via the total precursor mass flow rate, and the composition can be controlled by the molar ratio of Ag and Pd compounds in the precursor liquid.


Author(s):  
Gary Cooper ◽  
Jack Foster ◽  
Lee Galbraith ◽  
Sudhanshu Jain ◽  
Armand Neukermans ◽  
...  

The large-scale production of vast numbers of suitable salt nuclei and their upward launch is one of the main technological barriers to the experimental testing of marine cloud brightening (MCB). Very promising, though not definitive, results have been obtained using an adapted version of effervescent spray atomization. The process is simple, robust and inexpensive. This form of effervescent spraying uses only pressurized water and air sprayed from small nozzles to obtain very fine distributions. While it is far from optimized, and may not be the best method if full deployment is ever desired, we believe that even in its present form the process would lend itself well to preliminary field test investigations of MCB. Measurements obtained using standard aerosol instrumentation show approximately lognormal distributions of salt nuclei with median diameters of approximately 65 nm and geometric standard deviations slightly less than 2. However, these measurements are not in agreement with those based on scanning electron microscopy imaging of collected particles, an observation that has not yet been explained. Assuming the above distribution, 10 15 particles per second could be made with 21 kW of spray power, using approximately 200 nozzles. It is envisioned that existing snow making equipment can be adapted to launch the nuclei 60–100 m into the air, requiring approximately 20 kW of additional power.


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