Influence of Particle Surface Area Concentration on the Production of Organic Particulate Matter in a Continuously Mixed Flow Reactor

2019 ◽  
Vol 53 (9) ◽  
pp. 4968-4976 ◽  
Author(s):  
Yuemei Han ◽  
Zhaoheng Gong ◽  
Pengfei Liu ◽  
Suzane S. de Sá ◽  
Karena A. McKinney ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Surface Area ◽  
Flow Reactor ◽  
Particle Surface ◽  
Particle Surface Area ◽  
Mixed Flow ◽  
Organic Particulate Matter ◽  
Surface Area Concentration

Are bioleaching rates determined by the available particle surface area concentration?

2008 ◽  
Vol 25 (1) ◽  
pp. 101-106 ◽  
Author(s):  
Pedro Valencia ◽  
Fernando Acevedo
Keyword(s):  
Surface Area ◽  
Particle Surface ◽  
Particle Surface Area ◽  
Surface Area Concentration

Raman-lidar measurements of particle surface-area concentration in the stratosphere after the Mount Pinatubo eruption

1995 ◽  
Author(s):  
Ulla Wandinger ◽  
Albert Ansmann ◽  
Ina Mattis ◽  
Frank Wagner ◽  
Jens Reichardt ◽  
...  
Keyword(s):  
Surface Area ◽  
Particle Surface ◽  
Raman Lidar ◽  
Particle Surface Area ◽  
Mount Pinatubo ◽  
Lidar Measurements ◽  
Pinatubo Eruption ◽  
Surface Area Concentration

scholarly journals An experimental technique for the direct measurement of N<sub>2</sub>O<sub>5</sub> reactivity on ambient particles

2009 ◽  
Vol 2 (2) ◽  
pp. 689-723 ◽  
Author(s):  
T. H. Bertram ◽  
J. A. Thornton ◽  
T. P. Riedel
Keyword(s):  
Surface Area ◽  
Direct Measurement ◽  
Flow Reactor ◽  
Aerosol Particles ◽  
Particle Surface ◽  
Operating Conditions ◽  
Trace Gas ◽  
Ionization Mass ◽  
Particle Surface Area ◽  
Laboratory Investigations

Abstract. An experimental approach for the direct measurement of trace gas reactivity on ambient aerosol particles has been developed. The method utilizes a newly designed entrained aerosol flow reactor coupled to a custom-built chemical ionization mass spectrometer. The experimental method is described via application to the measurement of the N2O5 reaction probability, γ(N2O5). Laboratory investigations on well characterized aerosol particles show that measurements of γ(N2O5) observed with this technique are in agreement with previous observations, using conventional flow tube methods, to within ±20% at atmospherically relevant particle surface area concentrations (0–1000 μm2 cm−3). Uncertainty in the measured γ(N2O5) is discussed in the context of fluctuations in potential ambient biases (e.g., temperature, relative humidity and trace gas loadings). Under ambient operating conditions we estimate a single-point uncertainty in γ(N2O5) that ranges between ±(1.3×10−2+0.2×γ(N2O5)), and ±(1.3×10−3+0.2×γ(N2O5)) for particle surface area concentrations of 100 to 1000 μm2 cm−3, respectively. Examples from both laboratory investigations and field observations are included alongside discussion of future applications for the reactivity measurement and optimal deployment locations and conditions.

scholarly journals An experimental technique for the direct measurement of N<sub>2</sub>O<sub>5</sub> reactivity on ambient particles

2009 ◽  
Vol 2 (1) ◽  
pp. 231-242 ◽  
Author(s):  
T. H. Bertram ◽  
J. A. Thornton ◽  
T. P. Riedel
Keyword(s):  
Surface Area ◽  
Direct Measurement ◽  
Flow Reactor ◽  
Aerosol Particles ◽  
Particle Surface ◽  
Operating Conditions ◽  
Trace Gas ◽  
Ionization Mass ◽  
Particle Surface Area ◽  
Laboratory Investigations

Abstract. An experimental approach for the direct measurement of trace gas reactivity on ambient aerosol particles has been developed. The method utilizes a newly designed entrained aerosol flow reactor coupled to a custom-built chemical ionization mass spectrometer. The experimental method is described via application to the measurement of the N2O5 reaction probability, γ (N2O5). Laboratory investigations on well characterized aerosol particles show that measurements of γ (N2O5) observed with this technique are in agreement with previous observations, using conventional flow tube methods, to within ±20% at atmospherically relevant particle surface area concentrations (0–1000 μm2 cm−3). Uncertainty in the measured γ (N2O5) is discussed in the context of fluctuations in potential ambient biases (e.g., temperature, relative humidity and trace gas loadings). Under ambient operating conditions we estimate a single-point uncertainty in γ (N2O5) that ranges between ± (1.3×10-2 + 0.2×γ (N2O5)), and ± (1.3×10-3 + 0.2×γ (N2O5)) for particle surface area concentrations of 100 to 1000 μm2 cm−3, respectively. Examples from both laboratory investigations and field observations are included alongside discussion of future applications for the reactivity measurement and optimal deployment locations and conditions.

scholarly journals Mutual promotion effect between aerosol particle liquid water and nitrate formation lead to severe nitrate-dominated particulate matter pollution and low visibility

2019 ◽  
Author(s):  
Yu Wang ◽  
Ying Chen ◽  
Zhijun Wu ◽  
Dongjie Shang ◽  
Yuxuan Bian ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Surface Area ◽  
Aerosol Particle ◽  
Water Uptake ◽  
Liquid Water ◽  
Particle Surface ◽  
Particle Surface Area ◽  
Promotion Effect ◽  
Particulate Matter Pollution ◽  
Area And Volume

Abstract. As has been the case in North America and Western Europe, the SO2 emissions substantially reduced in North China Plain (NCP) in recent years. A dichotomy of reductions in SO2 and NOx concentrations result in the frequent occurrences of nitrate (pNO3−)-dominated particulate matter pollution over NCP. In this study, we observed a polluted episode with the nitrate mass fraction in non-refractory PM1 (NR-PM1) up to 44 % during wintertime in Beijing. Based on this typical pNO3−-dominated haze event, the linkage between aerosol water uptake and pNO3− formation, further impacting on visibility degradation, have been investigated based on field observations and theoretical calculations. During haze development, as ambient relative humidity (RH) increased from ~ 10 % up to 70 %, the aerosol particle liquid water increased from ~ 1 μg/m3 at the beginning to ~ 75 μg/m3 at the fully-developed haze period. Without considering the water uptake, the particle surface area and the volume concentrations increased by a factor of 4.1 and 4.8, respectively, during the development of haze event. Taking water uptake into account, the wet particle surface area and volume concentrations enhanced by a factor of 4.7 and 5.8, respectively. As a consequence, the hygroscopic growth of particles facilitated the condensational loss of dinitrogen pentoxide (N2O5) and nitric acid (HNO3) to particles contributing pNO3−. From the beginning to the fully-developed haze, the condensational loss of N2O5 increased by a factor of 20 when only considering aerosol surface area and volume of dry particles, while increasing by a factor of 25 considering extra surface area and volume due to water uptake. Similarly, the condensational loss of HNO3 increased by a factor of 2.7~2.9 and 3.1~3.5 for dry and wet aerosol surface area and volume from the beginning to the fully-developed haze period. Above results demonstrated that the pNO3− formation is further enhanced by aerosol water uptake with elevated ambient RH during haze development, in turn, facilitating the aerosol taking up water due to the hygroscopicity of nitrate salt. Such mutual promotion effect between aerosol particle liquid water and nitrate formation can rapidly degrade air quality and halve visibility within one day. Reduction of nitrogen-containing gaseous precursors, e.g., by control of traffic emissions, is essential in mitigating severe haze events in NCP.

Influence of particle surface area on the toxicity of insoluble manganese dioxide dusts

1997 ◽  
Vol 71 (12) ◽  
pp. 725-729 ◽  
Author(s):  
Dominique Lison ◽  
C&#x000E9;cile Lardot ◽  
Fran&#x000E7;ois Huaux ◽  
Giovanna Zanetti ◽  
Bice Fubini
Keyword(s):  
Manganese Dioxide ◽  
Surface Area ◽  
Particle Surface ◽  
Particle Surface Area

scholarly journals Effect of particle surface area on ice active site densities retrieved from droplet freezing spectra

2016 ◽  
Vol 16 (20) ◽  
pp. 13359-13378 ◽  
Author(s):  
Hassan Beydoun ◽  
Michael Polen ◽  
Ryan C. Sullivan
Keyword(s):  
Surface Area ◽  
Active Sites ◽  
Particle Surface ◽  
Active Surface ◽  
Freezing Temperature ◽  
Ice Nucleation ◽  
Critical Surface ◽  
Cold Plate ◽  
Particle Surface Area ◽  
Immersion Freezing

Abstract. Heterogeneous ice nucleation remains one of the outstanding problems in cloud physics and atmospheric science. Experimental challenges in properly simulating particle-induced freezing processes under atmospherically relevant conditions have largely contributed to the absence of a well-established parameterization of immersion freezing properties. Here, we formulate an ice active, surface-site-based stochastic model of heterogeneous freezing with the unique feature of invoking a continuum assumption on the ice nucleating activity (contact angle) of an aerosol particle's surface that requires no assumptions about the size or number of active sites. The result is a particle-specific property g that defines a distribution of local ice nucleation rates. Upon integration, this yields a full freezing probability function for an ice nucleating particle. Current cold plate droplet freezing measurements provide a valuable and inexpensive resource for studying the freezing properties of many atmospheric aerosol systems. We apply our g framework to explain the observed dependence of the freezing temperature of droplets in a cold plate on the concentration of the particle species investigated. Normalizing to the total particle mass or surface area present to derive the commonly used ice nuclei active surface (INAS) density (ns) often cannot account for the effects of particle concentration, yet concentration is typically varied to span a wider measurable freezing temperature range. A method based on determining what is denoted an ice nucleating species' specific critical surface area is presented and explains the concentration dependence as a result of increasing the variability in ice nucleating active sites between droplets. By applying this method to experimental droplet freezing data from four different systems, we demonstrate its ability to interpret immersion freezing temperature spectra of droplets containing variable particle concentrations. It is shown that general active site density functions, such as the popular ns parameterization, cannot be reliably extrapolated below this critical surface area threshold to describe freezing curves for lower particle surface area concentrations. Freezing curves obtained below this threshold translate to higher ns values, while the ns values are essentially the same from curves obtained above the critical area threshold; ns should remain the same for a system as concentration is varied. However, we can successfully predict the lower concentration freezing curves, which are more atmospherically relevant, through a process of random sampling from g distributions obtained from high particle concentration data. Our analysis is applied to cold plate freezing measurements of droplets containing variable concentrations of particles from NX illite minerals, MCC cellulose, and commercial Snomax bacterial particles. Parameterizations that can predict the temporal evolution of the frozen fraction of cloud droplets in larger atmospheric models are also derived from this new framework.

scholarly journals Salt enhanced solvent relaxation and particle surface area determination via rapid spin-lattice NMR

2018 ◽  
Vol 333 ◽  
pp. 458-467 ◽  
Author(s):  
Laura N. Elliott ◽  
Richard A. Bourne ◽  
Ali Hassanpour ◽  
John L. Edwards ◽  
Stephen Sutcliffe ◽  
...  
Keyword(s):  
Surface Area ◽  
Particle Surface ◽  
Solvent Relaxation ◽  
Particle Surface Area ◽  
Spin Lattice ◽  
Surface Area Determination ◽  
Area Determination

scholarly journals Biomass char particle surface area and porosity dynamics during gasification

Fuel ◽  
2020 ◽  
Vol 264 ◽  
pp. 116833 ◽  
Author(s):  
Ruochen Wu ◽  
Jacob Beutler ◽  
Cameron Price ◽  
Larry L. Baxter
Keyword(s):  
Surface Area ◽  
Particle Surface ◽  
Particle Surface Area ◽  
Char Particle ◽  
Biomass Char
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