نتایج جستجو برای: ozone

تعداد نتایج: 20569  

2000
Eugene C. Cordero

Ozone concentrations have been decreasing globally for the last 20 years in part due to increasing chlorine concentrations in the stratosphere (WMO 1999). The most dramatic example of these reductions has been identified in the high latitude southern hemisphere, where ozone levels are nearly entirely depleted in the lower stratosphere during September and October each year. This phenomenon, whi...

2008
Shiliang Wu Loretta J. Mickley Daniel J. Jacob David Rind David G. Streets

[1] We use a global chemical transport model (GEOS-Chem) driven by a general circulation model (NASA Goddard Institute for Space Studies GCM) to investigate the effects of 2000–2050 global change in climate and emissions (the Intergovernmental Panel on Climate Change A1B scenario) on the global tropospheric ozone budget and on the policy-relevant background (PRB) ozone in the United States. The...

Journal: :Global change biology 2013
Silvano Fares Rodrigo Vargas Matteo Detto Allen H Goldstein John Karlik Elena Paoletti Marcello Vitale

High ground-level ozone concentrations are typical of Mediterranean climates. Plant exposure to this oxidant is known to reduce carbon assimilation. Ozone damage has been traditionally measured through manipulative experiments that do not consider long-term exposure and propagate large uncertainty by up-scaling leaf-level observations to ecosystem-level interpretations. We analyzed long-term co...

2014
Hiromi Nagano Gotaro Shiota Hidetoshi Arakawa

Ozone is widely used for sterilization, deodorization, and cleaning. However, the effects of ozone on human are not well understood, because there is currently no reliable assay method for ozone. Therefore the accurate measurement of ozone is important for its safe use. Here, we report optimized conditions for use with fluorescein derivative 1 (probe 1). Under optimum conditions, probe 1 reacte...

2015
Joel A. Mathews David I. Kasahara Luiza Ribeiro Allison P. Wurmbrand Fernanda M. C. Ninin Stephanie A. Shore Shama Ahmad

We examined the role of γδ T cells in the induction of alternatively activated M2 macrophages and the resolution of inflammation after ozone exposure. Wildtype (WT) mice and mice deficient in γδ T cells (TCRδ-/- mice) were exposed to air or to ozone (0.3 ppm for up to 72h) and euthanized immediately or 1, 3, or 5 days after cessation of exposure. In WT mice, M2 macrophages accumulated in the lu...

2008
W. Lin

Regional ozone pollution has become one of the top environmental concerns in China, especially in those economically vibrant and densely populated regions, such as North China region including Beijing. To address this issue, surface ozone and ancillary data over the period 2004–2006 from the Shangdianzi Regional Background Station 5 in north China were analyzed. Due to the suitable location and...

Journal: :Tree physiology 1996
E Pääkkönen J Vahala T Holopainen R Karjalainen L Kärenlampi

Saplings of ozone-sensitive and ozone-tolerant birch (Betula pendula Roth.), clones B and C, respectively, were exposed to ozone concentrations that were 1.7-fold higher than ambient for one growing season under open-field conditions. Ambient air was used as the control treatment. In the ozone-sensitive clone B, there was an initial stimulation of leaf area growth in response to the ozone treat...

2014
S. Chatani M. Amann A. Goel J. Hao Z. Klimont A. Kumar A. Mishra S. Sharma S. X. Wang Y. X. Wang B. Zhao

A regional air quality simulation framework including the Weather Research and Forecasting modeling system (WRF), the Community Multi-scale Air Quality modeling system (CMAQ), and precursor emissions to simulate tropospheric ozone over South and East Asia is introduced. Concentrations of tropospheric ozone and related species simulated by the framework are validated by comparing with observatio...

2013
D. T. Shindell

The new generation GISS climate model includes fully interactive chemistry related to ozone in historical and future simulations, and interactive methane in future simulations. Evaluation of ozone, its tropospheric precursors, and methane shows that the model captures much of the largescale spatial structure seen in recent observations. While the model is much improved compared with the previou...

2011
I. Petropavlovskikh R. Evans G. McConville S. Oltmans D. Quincy K. Lantz P. Disterhoft M. Stanek

Remote sounding methods are used to derive ozone profile and column information from various groundbased and satellite measurements. Vertical ozone profiles measured in Dobson units (DU) are currently retrieved based on laboratory measurements of the ozone absorption crosssection spectrum between 270 and 400 nm published in 1985 by Bass and Paur (BP). Recently, the US National Aeronautics and S...

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