Submicron particles from coal combustion

1979 ◽  
Vol 17 (1) ◽  
pp. 97-104 ◽  
Author(s):  
Richard C. Flagan
2013 ◽  
Vol 13 (4) ◽  
pp. 10809-10858 ◽  
Author(s):  
W. W. Hu ◽  
M. Hu ◽  
B. Yuan ◽  
J. L. Jimenez ◽  
Q. Tang ◽  
...  

Abstract. In order to understand the aging and processing of organic aerosols (OA), an intensive field campaign (Campaign of Air Pollution at Typical Coastal Areas In Eastern China, CAPTAIN) was conducted in March–April at a receptor site (Changdao Island) in Central Eastern China. Multiple fast aerosol and gas measurement instruments were used during the campaign, including a high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was applied to measure mass concentrations and non-refractory chemical components of submicron particles (PM1nr). The average mass concentration of PM1 (PM1nr + black carbon) was 47 ± 36 μg m−3 during the campaign and showed distinct variation depending on back trajectories and their overlap with source regions. Organic aerosol (OA) is the largest component of PM1 (30%), followed by nitrate (28%), sulfate (19%), ammonium (15%), black carbon (6%), and chloride (3%). Four OA components were resolved by Positive Matrix Factorization (PMF) of the high-resolution spectra, including low-volatility oxygenated organic aerosol (LV-OOA), semi-volatile oxygenated OA (SV-OOA), hydrocarbon-like OA (HOA) and a coal combustion OA (CCOA), reported here for the first time. The mass spectrum of CCOA has high abundance of fragments from polycyclic aromatic hydrocarbons (PAHs) (m/z 128, 152, 178 etc.). The average atomic ratio of oxygen to carbon in OA (O/C) at Changdao is 0.59, which is comparable to other field studies reported at locations downwind of large pollution sources, indicating the oxidized nature of most OA during the campaign. The evolution of OA elemental composition in the Van Krevelen diagram (H/C vs. O/C) shows a slope of −0.63, however, the OA influenced by coal combution exhibits a completely different evolution that appears dominated by physical mixing. The aging of organic aerosols vs. with photochemical age was investigated. It is shown that OA/ΔCO, as well as LV-OOA/ΔCO and SV-OOA/ΔCO, positively correlated with photochemical age. LV-OOA accounted for 73% of the OA secondary formation in the oldest plumes (photochemical age of 25 h). The kOH at Changdao by assuming SOA formation and aging as a first-order process proportional to OH was calculated to be is 5.2 × 10−12 cm3 molec−1 s−1 which is similar to those determined in recent studies of polluted air in other continents.


2020 ◽  
Vol 224 ◽  
pp. 117308 ◽  
Author(s):  
Qin Yan ◽  
Shaofei Kong ◽  
Yingying Yan ◽  
Haibiao Liu ◽  
Wei Wang ◽  
...  

2013 ◽  
Vol 13 (19) ◽  
pp. 10095-10112 ◽  
Author(s):  
W. W. Hu ◽  
M. Hu ◽  
B. Yuan ◽  
J. L. Jimenez ◽  
Q. Tang ◽  
...  

Abstract. In order to understand the aging and processing of organic aerosols (OA), an intensive field campaign (Campaign of Air Pollution at Typical Coastal Areas IN Eastern China, CAPTAIN) was conducted March–April at a receptor site (a Changdao island) in central eastern China. Multiple fast aerosol and gas measurement instruments were used during the campaign, including a high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) that was applied to measure mass concentrations and non-refractory chemical components of submicron particles (PM1nr). The average mass concentration of PM1(PM1nr+black carbon) was 47 ± 36 μg m−3 during the campaign and showed distinct variation, depending on back trajectories and their overlap with source regions. Organic aerosol (OA) is the largest component of PM1 (30%), followed by nitrate (28%), sulfate (19%), ammonium (15%), black carbon (6%), and chloride (3%). Four OA components were resolved by positive matrix factorization (PMF) of the high-resolution spectra, including low-volatility oxygenated organic aerosol (LV-OOA), semi-volatile oxygenated OA (SV-OOA), hydrocarbon-like OA (HOA) and a coal combustion OA (CCOA). The mass spectrum of CCOA had high abundance of fragments from polycyclic aromatic hydrocarbons (PAHs) (m/z 128, 152, 178, etc.). The average atomic ratio of oxygen to carbon in OA (O / C) at Changdao was 0.59, which is comparable to other field studies reported at locations downwind of large pollution sources, indicating the oxidized nature of most OA during the campaign. The evolution of OA elemental composition in the van Krevelen diagram (H / C vs. O / C) showed a slope of −0.63; however, the OA influenced by coal combustion exhibits a completely different evolution that appears dominated by physical mixing. The aging of organic aerosols vs. photochemical age was investigated. It was shown that OA / ΔCO, as well as LV-OOA / ΔCO and SV-OOA / ΔCO, positively correlated with photochemical age. LV-OOA accounted for 73% of the OA secondary formation (SOA) in the oldest plumes (photochemical age of 25 h). The kOH at Changdao, by assuming SOA formation and aging as a first-order process proportional to OH, was calculated to be 5.2 × 10−12 cm3 molec.−1 s−1, which is similar to those determined in recent studies of polluted air in other continents.


2016 ◽  
Vol 562 ◽  
pp. 812-821 ◽  
Author(s):  
J.K. Zhang ◽  
M.T. Cheng ◽  
D.S. Ji ◽  
Z.R. Liu ◽  
B. Hu ◽  
...  

Author(s):  
James S. Webber

INTRODUCTION“Acid rain” and “acid deposition” are terms no longer confined to the lexicon of atmospheric scientists and 1imnologists. Public awareness of and concern over this phenomenon, particularly as it affects acid-sensitive regions of North America, have increased dramatically in the last five years. Temperate ecosystems are suffering from decreased pH caused by acid deposition. Human health may be directly affected by respirable sulfates and by the increased solubility of toxic trace metals in acidified waters. Even man's monuments are deteriorating as airborne acids etch metal and stone features.Sulfates account for about two thirds of airborne acids with wet and dry deposition contributing equally to acids reaching surface waters or ground. The industrial Midwest is widely assumed to be the source of most sulfates reaching the acid-sensitive Northeast since S02 emitted as a byproduct of coal combustion in the Midwest dwarfs S02 emitted from all sources in the Northeast.


Author(s):  
C.M. Teng ◽  
T.F. Kelly ◽  
J.P. Zhang ◽  
H.M. Lin ◽  
Y.W. Kim

Spherical submicron particles of materials produced by electrohydrodynamic (EHD) atomization have been used to study a variety of materials processes including nucleation of alternative crystallization phases in iron-nickel and nickel-chromium alloys, amorphous solidification in submicron droplets of pure metals, and quasi-crystal formation in nickel-chromium alloys. Some experiments on pure nickel, nickel oxide single crystals, the nickel/nickel(II) oxide interface, and grain boundaries in nickel monoxide have been performed by STEM. For these latter studies, HREM is the most direct approach to obtain particle crystal structures at the atomic level. Grain boundaries in nickel oxide have also been investigated by HREM. In this paper, we present preliminary results of HREM observations of NiO growth on submicron spheres of pure nickel.Small particles of pure nickel were prepared by EHD atomization. For the study of pure nickel, 0.5 mm diameter pure nickel wire (99.9975%) is sprayed directly in the EHD process. The liquid droplets solidify in free-flight through a vacuum chamber operated at about 10-7 torr.


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