The Experts below are selected from a list of 2832 Experts worldwide ranked by ideXlab platform
Xinming Wang - One of the best experts on this subject based on the ideXlab platform.
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particle number concentration size distribution and chemical composition during haze and Photochemical Smog episodes in shanghai
Journal of Environmental Sciences-china, 2014Co-Authors: Xuemei Wang, Jianmin Chen, Tiantao Cheng, Renyi Zhang, Xinming WangAbstract:The aerosol number concentration and size distribution as well as size-resolved particle chemical composition were measured during haze and Photochemical Smog episodes in Shanghai in 2009. The number of haze days accounted for 43%, of which 30% was severe (visibility<2km) and moderate (2km≤visibility<3km) haze, mainly distributed in winter and spring. The mean particle number concentration was about 17,000/cm(3) in haze, more than 2 times that in clean days. The greatest increase of particle number concentration was in 0.5-1μm and 1-10μm size fractions during haze events, about 17.78 times and 8.78 times those of clean days. The largest increase of particle number concentration was within 50-100nm and 100-200nm fractions during Photochemical Smog episodes, about 5.89 times and 4.29 times those of clean days. The particle volume concentration and surface concentration in haze, Photochemical Smog and clean days were 102, 49, 15μm(3)/cm(3) and 949, 649, 206μm(2)/cm(3), respectively. As haze events got more severe, the number concentration of particles smaller than 50nm decreased, but the particles of 50-200nm and 0.5-1μm increased. The diurnal variation of particle number concentration showed a bimodal pattern in haze days. All soluble ions were increased during haze events, of which NH4(+), SO4(2-) and NO3(-) increased greatly, followed by Na(+), K(+), Ca(2+) and Cl(-). These ions were very different in size-resolved particles during haze and Photochemical Smog episodes.
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particle number concentration size distribution and chemical composition during haze and Photochemical Smog episodes in shanghai
Journal of Environmental Sciences-china, 2014Co-Authors: Xuemei Wang, Jianmin Chen, Tiantao Cheng, Renyi Zhang, Xinming WangAbstract:Abstract The aerosol number concentration and size distribution as well as size-resolved particle chemical composition were measured during haze and Photochemical Smog episodes in Shanghai in 2009. The number of haze days accounted for 43%, of which 30% was severe (visibility 3 in haze, more than 2 times that in clean days. The greatest increase of particle number concentration was in 0.5–1 μm and 1–10 μm size fractions during haze events, about 17.78 times and 8.78 times those of clean days. The largest increase of particle number concentration was within 50–100 nm and 100–200 nm fractions during Photochemical Smog episodes, about 5.89 times and 4.29 times those of clean days. The particle volume concentration and surface concentration in haze, Photochemical Smog and clean days were 102, 49, 15 μm 3 /cm 3 and 949, 649, 206 μm 2 /cm 3 , respectively. As haze events got more severe, the number concentration of particles smaller than 50 nm decreased, but the particles of 50–200 nm and 0.5–1 μm increased. The diurnal variation of particle number concentration showed a bimodal pattern in haze days. All soluble ions were increased during haze events, of which NH 4 + , SO 4 2 − and NO 3 − increased greatly, followed by Na + , K + , Ca 2 + and Cl − . These ions were very different in size-resolved particles during haze and Photochemical Smog episodes.
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on the relationship between ozone and its precursors in the pearl river delta application of an observation based model obm
Environmental Science and Pollution Research, 2010Co-Authors: Hairong Cheng, Xinming Wang, Hai Guo, Sam Saunders, S H M Lam, Fei Jiang, Tijian Wang, Aijun Ding, Shuncheng LeeAbstract:Background, aim, and scope Photochemical Smog, characterized by high concentrations of O3 and fine particles, is of great concern in the urban areas, in particular megacities and city clusters like the Pearl River Delta.
Xuemei Wang - One of the best experts on this subject based on the ideXlab platform.
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particle number concentration size distribution and chemical composition during haze and Photochemical Smog episodes in shanghai
Journal of Environmental Sciences-china, 2014Co-Authors: Xuemei Wang, Jianmin Chen, Tiantao Cheng, Renyi Zhang, Xinming WangAbstract:The aerosol number concentration and size distribution as well as size-resolved particle chemical composition were measured during haze and Photochemical Smog episodes in Shanghai in 2009. The number of haze days accounted for 43%, of which 30% was severe (visibility<2km) and moderate (2km≤visibility<3km) haze, mainly distributed in winter and spring. The mean particle number concentration was about 17,000/cm(3) in haze, more than 2 times that in clean days. The greatest increase of particle number concentration was in 0.5-1μm and 1-10μm size fractions during haze events, about 17.78 times and 8.78 times those of clean days. The largest increase of particle number concentration was within 50-100nm and 100-200nm fractions during Photochemical Smog episodes, about 5.89 times and 4.29 times those of clean days. The particle volume concentration and surface concentration in haze, Photochemical Smog and clean days were 102, 49, 15μm(3)/cm(3) and 949, 649, 206μm(2)/cm(3), respectively. As haze events got more severe, the number concentration of particles smaller than 50nm decreased, but the particles of 50-200nm and 0.5-1μm increased. The diurnal variation of particle number concentration showed a bimodal pattern in haze days. All soluble ions were increased during haze events, of which NH4(+), SO4(2-) and NO3(-) increased greatly, followed by Na(+), K(+), Ca(2+) and Cl(-). These ions were very different in size-resolved particles during haze and Photochemical Smog episodes.
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particle number concentration size distribution and chemical composition during haze and Photochemical Smog episodes in shanghai
Journal of Environmental Sciences-china, 2014Co-Authors: Xuemei Wang, Jianmin Chen, Tiantao Cheng, Renyi Zhang, Xinming WangAbstract:Abstract The aerosol number concentration and size distribution as well as size-resolved particle chemical composition were measured during haze and Photochemical Smog episodes in Shanghai in 2009. The number of haze days accounted for 43%, of which 30% was severe (visibility 3 in haze, more than 2 times that in clean days. The greatest increase of particle number concentration was in 0.5–1 μm and 1–10 μm size fractions during haze events, about 17.78 times and 8.78 times those of clean days. The largest increase of particle number concentration was within 50–100 nm and 100–200 nm fractions during Photochemical Smog episodes, about 5.89 times and 4.29 times those of clean days. The particle volume concentration and surface concentration in haze, Photochemical Smog and clean days were 102, 49, 15 μm 3 /cm 3 and 949, 649, 206 μm 2 /cm 3 , respectively. As haze events got more severe, the number concentration of particles smaller than 50 nm decreased, but the particles of 50–200 nm and 0.5–1 μm increased. The diurnal variation of particle number concentration showed a bimodal pattern in haze days. All soluble ions were increased during haze events, of which NH 4 + , SO 4 2 − and NO 3 − increased greatly, followed by Na + , K + , Ca 2 + and Cl − . These ions were very different in size-resolved particles during haze and Photochemical Smog episodes.
Jack R Harkema - One of the best experts on this subject based on the ideXlab platform.
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innate lymphoid cells mediate pulmonary eosinophilic inflammation airway mucous cell metaplasia and type 2 immunity in mice exposed to ozone
Toxicologic Pathology, 2017Co-Authors: Kazuyoshi Kumagai, James G Wagner, Daven N Jacksonhumbles, Nicholas Buglak, Kaylin White, Steven J Van Dyken, Ryan P Lewandowski, Ning Li, Jack R HarkemaAbstract:Exposure to elevated levels of ambient ozone in Photochemical Smog is associated with eosinophilic airway inflammation and nonatopic asthma in children. In the present study, we determined the role of innate lymphoid cells (ILCs) in the pathogenesis of ozone-induced nonatopic asthma by using lymphoid cell-sufficient C57BL/6 mice, ILC-sufficient Rag2−/− mice (devoid of T and B cells), and ILC-deficient Rag2−/−Il2rg−/− mice (depleted of all lymphoid cells including ILCs). Mice were exposed to 0 or 0.8 parts per million ozone for 1 day or 9 consecutive weekdays (4 hr/day). A single exposure to ozone caused neutrophilic inflammation, airway epithelial injury, and reparative DNA synthesis in all strains of mice, irrespective of the presence or absence of ILCs. In contrast, 9-day exposures induced eosinophilic inflammation and mucous cell metaplasia only in the lungs of ILC-sufficient mice. Repeated ozone exposures also elicited increased messenger RNA expression of transcripts associated with type 2 immunity a...
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subacute inhalation exposure to ozone induces systemic inflammation but not insulin resistance in a diabetic mouse model
Inhalation Toxicology, 2016Co-Authors: Zhekang Ying, James G Wagner, Ryan P Lewandowski, Katryn Allen, Jixin Zhong, Minjie Chen, Keisha Williams, Sanjay Rajagopalan, Jack R HarkemaAbstract:AbstractEpidemiological studies suggest that diabetics may be more susceptible to the adverse health effects from exposure to high ambient concentrations of ozone, the primary oxidant gas in Photochemical Smog. While increased morbidity and mortality from ozone inhalation has been linked to disruption of normal cardiovascular and airway functions, potential effects on glucose and insulin homeostasis are not understood. We tested the hypothesis that ozone exposure would worsen metabolic homeostasis in KKAy mice, a genetic diabetic animal model. Male KKAy mice were exposed to 0.5 ppm ozone for 13 consecutive weekdays, and then assessed for airway, adipose and systemic inflammation, glucose homeostasis, and insulin signaling. Ozone exposure increased plasma TNFα, as well as expression of VCAM-1, iNOS and IL-6 in both pulmonary and adipose tissues. Pro-inflammatory CD11b+Gr-1lo7/4hi macrophages were increased by 200% in adipose tissue, but unchanged in blood. Interestingly, glucose levels were not significant...
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non allergic models of mucous cell metaplasia and mucus hypersecretion in rat nasal and pulmonary airways
Novartis Foundation Symposium, 2002Co-Authors: Jack R Harkema, James G WagnerAbstract:: Mucous cell proliferation and hypersecretion of airway mucus are important pathological features of human respiratory disorders such as asthma and chronic bronchitis. In addition to airborne allergens and infectious agents, inhaled chemical irritants such as ozone and cigarette smoke have been demonstrated to induce changes in airway mucus production. Cellular and molecular mechanisms involved in non-allergic, toxicant-induced mucous cell metaplasia (MCM; transformation of airway epithelium, normally devoid of mucous cells, to secretory epithelium containing numerous mucus-secreting cells) are still unclear. We have used two experimental models of toxicant-induced MCM in the airways of rats to study the epithelial and inflammatory factors involved in the pathogenesis of MCM. Mucin-specific gene expression and MCM are induced in the nasal transitional epithelium (NTE), but not in the bronchiolar epithelium of F344 rats acutely exposed to ozone, an important air pollutant of Photochemical Smog. Inhalation of endotoxin, a lipopolysaccharide-protein molecule of gram-negative bacteria, induces MCM in the bronchiolar epithelium, but not in the NTE, of rats. Both ozone- and endotoxin-induced MCM are dependent on neutrophilic inflammation. Interestingly, each toxicant enhances the MCM induced by the other toxicant. These synergistic effects elicited by coexposure to ozone and endotoxin are also mediated, in part, by neutrophils.
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fluticasone propionate attenuates ozone induced rhinitis and mucous cell metaplasia in rat nasal airway epithelium
American Journal of Respiratory Cell and Molecular Biology, 1998Co-Authors: Jon A Hotchkiss, Roger Hilaski, Patty Spencer, Kate Slack, Karen Regan, Jack R HarkemaAbstract:Ozone (O3) is the principal oxidant pollutant in Photochemical Smog. Repeated exposures to O3 induces inflammation and mucous cell metaplasia in the nasal airways of laboratory animals. Our study was designed to determine the efficacy of a topical anti-inflammatory corticosteroid in preventing O3-induced rhinitis and mucous cell metaplasia in rat nasal epithelium. Male F344 rats were exposed to filtered air (0 ppm O3; air-controls) or 0.5 ppm O3, 8 h/day, for 3 or 5 days. Immediately before and after each exposure, rats received an intranasal instillation (50 μl/nasal passage) of a topical corticosteroid, fluticasone propionate (FP; 25 μg/nasal passage) or its vehicle only (0.01% ethanol in saline). Rats were killed 2 h after the third exposure (3-day exposure) or 3 days after the fifth exposure (5-day exposure) and nasal tissues were processed for light microscopy. Numeric densities of epithelial cells and neutrophils, and the amount of intraepithelial mucosubstances (IM) in the epithelium lining the max...
Jianmin Chen - One of the best experts on this subject based on the ideXlab platform.
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particle number concentration size distribution and chemical composition during haze and Photochemical Smog episodes in shanghai
Journal of Environmental Sciences-china, 2014Co-Authors: Xuemei Wang, Jianmin Chen, Tiantao Cheng, Renyi Zhang, Xinming WangAbstract:The aerosol number concentration and size distribution as well as size-resolved particle chemical composition were measured during haze and Photochemical Smog episodes in Shanghai in 2009. The number of haze days accounted for 43%, of which 30% was severe (visibility<2km) and moderate (2km≤visibility<3km) haze, mainly distributed in winter and spring. The mean particle number concentration was about 17,000/cm(3) in haze, more than 2 times that in clean days. The greatest increase of particle number concentration was in 0.5-1μm and 1-10μm size fractions during haze events, about 17.78 times and 8.78 times those of clean days. The largest increase of particle number concentration was within 50-100nm and 100-200nm fractions during Photochemical Smog episodes, about 5.89 times and 4.29 times those of clean days. The particle volume concentration and surface concentration in haze, Photochemical Smog and clean days were 102, 49, 15μm(3)/cm(3) and 949, 649, 206μm(2)/cm(3), respectively. As haze events got more severe, the number concentration of particles smaller than 50nm decreased, but the particles of 50-200nm and 0.5-1μm increased. The diurnal variation of particle number concentration showed a bimodal pattern in haze days. All soluble ions were increased during haze events, of which NH4(+), SO4(2-) and NO3(-) increased greatly, followed by Na(+), K(+), Ca(2+) and Cl(-). These ions were very different in size-resolved particles during haze and Photochemical Smog episodes.
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particle number concentration size distribution and chemical composition during haze and Photochemical Smog episodes in shanghai
Journal of Environmental Sciences-china, 2014Co-Authors: Xuemei Wang, Jianmin Chen, Tiantao Cheng, Renyi Zhang, Xinming WangAbstract:Abstract The aerosol number concentration and size distribution as well as size-resolved particle chemical composition were measured during haze and Photochemical Smog episodes in Shanghai in 2009. The number of haze days accounted for 43%, of which 30% was severe (visibility 3 in haze, more than 2 times that in clean days. The greatest increase of particle number concentration was in 0.5–1 μm and 1–10 μm size fractions during haze events, about 17.78 times and 8.78 times those of clean days. The largest increase of particle number concentration was within 50–100 nm and 100–200 nm fractions during Photochemical Smog episodes, about 5.89 times and 4.29 times those of clean days. The particle volume concentration and surface concentration in haze, Photochemical Smog and clean days were 102, 49, 15 μm 3 /cm 3 and 949, 649, 206 μm 2 /cm 3 , respectively. As haze events got more severe, the number concentration of particles smaller than 50 nm decreased, but the particles of 50–200 nm and 0.5–1 μm increased. The diurnal variation of particle number concentration showed a bimodal pattern in haze days. All soluble ions were increased during haze events, of which NH 4 + , SO 4 2 − and NO 3 − increased greatly, followed by Na + , K + , Ca 2 + and Cl − . These ions were very different in size-resolved particles during haze and Photochemical Smog episodes.
Tiantao Cheng - One of the best experts on this subject based on the ideXlab platform.
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particle number concentration size distribution and chemical composition during haze and Photochemical Smog episodes in shanghai
Journal of Environmental Sciences-china, 2014Co-Authors: Xuemei Wang, Jianmin Chen, Tiantao Cheng, Renyi Zhang, Xinming WangAbstract:The aerosol number concentration and size distribution as well as size-resolved particle chemical composition were measured during haze and Photochemical Smog episodes in Shanghai in 2009. The number of haze days accounted for 43%, of which 30% was severe (visibility<2km) and moderate (2km≤visibility<3km) haze, mainly distributed in winter and spring. The mean particle number concentration was about 17,000/cm(3) in haze, more than 2 times that in clean days. The greatest increase of particle number concentration was in 0.5-1μm and 1-10μm size fractions during haze events, about 17.78 times and 8.78 times those of clean days. The largest increase of particle number concentration was within 50-100nm and 100-200nm fractions during Photochemical Smog episodes, about 5.89 times and 4.29 times those of clean days. The particle volume concentration and surface concentration in haze, Photochemical Smog and clean days were 102, 49, 15μm(3)/cm(3) and 949, 649, 206μm(2)/cm(3), respectively. As haze events got more severe, the number concentration of particles smaller than 50nm decreased, but the particles of 50-200nm and 0.5-1μm increased. The diurnal variation of particle number concentration showed a bimodal pattern in haze days. All soluble ions were increased during haze events, of which NH4(+), SO4(2-) and NO3(-) increased greatly, followed by Na(+), K(+), Ca(2+) and Cl(-). These ions were very different in size-resolved particles during haze and Photochemical Smog episodes.
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particle number concentration size distribution and chemical composition during haze and Photochemical Smog episodes in shanghai
Journal of Environmental Sciences-china, 2014Co-Authors: Xuemei Wang, Jianmin Chen, Tiantao Cheng, Renyi Zhang, Xinming WangAbstract:Abstract The aerosol number concentration and size distribution as well as size-resolved particle chemical composition were measured during haze and Photochemical Smog episodes in Shanghai in 2009. The number of haze days accounted for 43%, of which 30% was severe (visibility 3 in haze, more than 2 times that in clean days. The greatest increase of particle number concentration was in 0.5–1 μm and 1–10 μm size fractions during haze events, about 17.78 times and 8.78 times those of clean days. The largest increase of particle number concentration was within 50–100 nm and 100–200 nm fractions during Photochemical Smog episodes, about 5.89 times and 4.29 times those of clean days. The particle volume concentration and surface concentration in haze, Photochemical Smog and clean days were 102, 49, 15 μm 3 /cm 3 and 949, 649, 206 μm 2 /cm 3 , respectively. As haze events got more severe, the number concentration of particles smaller than 50 nm decreased, but the particles of 50–200 nm and 0.5–1 μm increased. The diurnal variation of particle number concentration showed a bimodal pattern in haze days. All soluble ions were increased during haze events, of which NH 4 + , SO 4 2 − and NO 3 − increased greatly, followed by Na + , K + , Ca 2 + and Cl − . These ions were very different in size-resolved particles during haze and Photochemical Smog episodes.