scholarly journals Long Term Observation of Atmospheric Aerosols at Sakai, Osaka, Japan

1970 ◽  
Vol 8 (3) ◽  
pp. 72-74
Author(s):  
Norio Ito ◽  
Akira Mizohata
Keyword(s):  
Atmospheric Aerosols ◽  
Fine Particles ◽  
Low Pressure ◽  
Coarse Particles ◽  
Nitrate Ions ◽  
Long Term Observation ◽  
Andersen Sampler

We have continuously observed the aerosols with 3 kinds of samplers; automatic daily sampler (DS), Andersen sampler (AS) and Low pressure Andersen Sampler (LPAS) at Sakai, Osaka, Japan. We started these sampling from 1986 (DS), 1993 (AS) and 2000 (LPAS). Yearly mean of fine particles (< 2.1μm) has decreased by about 10 μg/m3 from 1993 to 2009. By contrast the coarse particles (> 2.1μm) do not have explicit decrease. The main constituents in fine particles are carbon matters (EC and OC) and ions (sulphate and nitrate). Ions do not have decrease trend. These trends indicate that the decrease of fine particles might be caused by the decrease of carbon matters. DOI: http://dx.doi.org/10.3126/jie.v8i3.5933 JIE 2011; 8(3): 72-74

scholarly journals Size-resolved exposure risk of persistent free radicals (PFRs) in atmospheric aerosols and their potential sources

2020 ◽  
Vol 20 (22) ◽  
pp. 14407-14417
Author(s):  
Qingcai Chen ◽  
Haoyao Sun ◽  
Wenhuai Song ◽  
Fang Cao ◽  
Chongguo Tian ◽  
...  
Keyword(s):  
Free Radicals ◽  
Health Risks ◽  
Atmospheric Aerosols ◽  
Fine Particles ◽  
Atmospheric Particulate Matter ◽  
Particle Sizes ◽  
Coarse Particles ◽  
Upper Respiratory Tract ◽  
Potential Health ◽  
Combustion Sources

Abstract. Environmentally persistent free radicals (EPFRs) are a new type of substance with potential health risks. EPFRs are widely present in atmospheric particulates, but there is a limited understanding of the size-resolved health risks of these radicals. This study reports the exposure risks and source of EPFRs in atmospheric particulate matter (PM) of different particle sizes (<10 µm) in Linfen, a typical coal-burning city in China. The type of EPFRs in fine particles (< 2.1 µm) is different from that in coarse particles (2.1–10 µm) in both winter and summer. However, the EPFR concentration is higher in coarse particles than in fine particles in summer, and the opposite trend is found in winter. In both seasons, combustion sources are the main sources of EPFRs, with coal combustion as the major contributor in winter, while other fuels are the major source in summer. Dust contributes part of the EPFRs, and it is mainly present in coarse particles in winter and the opposite in summer. The upper respiratory tract was found to be the area with the highest risk of exposure to EPFRs of the studied aerosols, with an exposure equivalent to that of approximately 21 cigarettes per person per day. Alveolar exposure to EPFRs is equivalent to 8 cigarettes per person per day, with combustion sources contributing the most to EPFRs in the alveoli. This study helps us to better understand the potential health risks of atmospheric PM with different particle sizes.

scholarly journals Impact of Gobi desert dust on aerosol chemistry of Xi'an, inland China during spring 2009: differences in composition and size distribution between the urban ground surface and the mountain atmosphere

2013 ◽  
Vol 13 (2) ◽  
pp. 819-835 ◽  
Author(s):  
G. H. Wang ◽  
B. H. Zhou ◽  
C. L. Cheng ◽  
J. J. Cao ◽  
J. J. Li ◽  
...  
Keyword(s):  
Size Distribution ◽  
Atmospheric Aerosols ◽  
Fine Particles ◽  
Major Ions ◽  
Heterogeneous Reaction ◽  
Ground Surface ◽  
Sampling Period ◽  
Gobi Desert ◽  
Coarse Particles ◽  
Dust Event

Abstract. Composition and size distribution of atmospheric aerosols from Xi'an city (~400 m, altitude) in inland China during the spring of 2009 including a massive dust event on 24 April were measured and compared with a parallel measurement at the summit (2060 m, altitude) of Mt. Hua, an alpine site nearby Xi'an. EC (elemental carbon), OC (organic carbon) and major ions in the city were 2–22 times higher than those on the mountaintop during the whole sampling period. Compared to that in the non-dust period a sharp increase in OC was observed at both sites during the dust period, which was mainly caused by an input of biogenic organics from the Gobi desert. However, adsorption/heterogeneous reaction of gaseous organics with dust was another important source of OC in the urban, contributing 22% of OC in the dust event. In contrast to the mountain atmosphere where fine particles were less acidic when dust was present, the urban fine particles became more acidic in the dust event than in the non-dust event, mainly due to enhanced heterogeneous formation of nitrate and diluted NH3. Cl− and NO3− in the urban air during the dust event significantly shifted toward coarse particles. Such redistributions were further pronounced on the mountaintop when dust was present, resulting in both ions almost entirely staying in coarse particles. On the contrary, no significant spatial difference in size distribution of SO42− was found between the urban ground surface and the mountain atmosphere, which dominated in the fine mode (<2.1 μm) during the nonevent and comparably distributed in the fine (<2.1 μm) and coarse (>2.1 μm) modes during the dust event.

scholarly journals Contribution of Fine Particles to Air Emission at Different Phases of Biomass Burning

Atmosphere ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 278 ◽  
Author(s):  
Niloofar Ordou ◽  
Igor E. Agranovski
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Fine Particles ◽  
Combustion Process ◽  
Coarse Particles ◽  
Biomass Smoke ◽  
Smoke Particles ◽  
Air Emission ◽  
Entire Duration ◽  
Diffusion Properties

Particle size distribution in biomass smoke was observed for different burning phases, including flaming and smouldering, during the combustion of nine common Australian vegetation representatives. Smoke particles generated during the smouldering phase of combustions were found to be coarser as compared to flaming aerosols for all hard species. In contrast, for leafy species, this trend was inversed. In addition, the combustion process was investigated over the entire duration of burning by acquiring data with one second time resolution for all nine species. Particles were separately characterised in two categories: fine particles with dominating diffusion properties measurable with diffusion-based instruments (Dp < 200 nm), and coarse particles with dominating inertia (Dp > 200 nm). It was found that fine particles contribute to more than 90 percent of the total fresh smoke particles for all investigated species.

scholarly journals SAT0137 Long-term observation of fibromyalgia patients

2001 ◽  
Author(s):  
L Szczepanski ◽  
C Stepniak ◽  
B Targonska-Stepniak
Keyword(s):  
Long Term Observation

scholarly journals Photocatalytic Activity Enhancement of Low-pressure Cold-Sprayed TiO2 Coatings Induced by Long-term Water Vapor Exposure

2021 ◽  
Author(s):  
Seremak Wioletta ◽  
Baszczuk Agnieszka ◽  
Jasiorski Marek ◽  
Gibas Anna ◽  
Winnicki Marcin
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Water Vapor ◽  
Sol Gel ◽  
Low Pressure ◽  
Oxygen Depletion ◽  
Amorphous Structure ◽  
Industrial Applications ◽  
Additional Parameter

AbstractThis work shows that the titanium dioxide coatings obtained by low-pressure cold gas spraying with the use of the sol–gel amorphous TiO2 powder are characterized by photocatalytic activity despite their partial amorphous content. Moreover, the research outcome suggests that the decomposition rate of organic pollutants is enhanced after long-term exposure to moisture. The condensation humidity test is not detrimental to the continuity and integrity of the coating, but the phase composition of coatings changes—with the exposure to water vapor, the portion of the amorphous phase crystallizes into brookite. The mechanism responsible for the conversion of amorphous TiO2 into brookite is attributed to the water-driven dissolution and reprecipitation of TiO6 octahedra. It has been shown that an additional parameter necessary for the stabilization of the brookite is the oxygen depletion of the amorphous structure of titanium dioxide. Considering the results presented in this paper and the advantages of a portable, low-pressure cold spray system for industrial applications, it is expected that TiO2 coatings produced from a sol–gel feedstock powder can be further developed and tested as efficient photocatalysts.

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