نتایج جستجو برای: ozone

تعداد نتایج: 20569  

Journal: :Environmental pollution 2001
S Syri M Amann W Schöpp C Heyes

Tropospheric ozone concentrations regarded as harmful for human health are frequently encountered in Central Europe in summertime. Although ozone formation generally results from precursors transported over long distances, in urban areas local effects, such as reactions due to nearby emission sources, play a major role in determining ozone concentrations. Europe-wide mapping and modeling of pop...

2005
R. Müller

Tracer-tracer relations have been used for a long time to separate physico-chemical change from change caused by transport processes. In particular, for more than a decade, ozone-tracer relations have been used to quantify chemical ozone loss in the polar vortex. The application of ozone-tracer relations for quantifying ozone loss relies on two hypotheses: that a compact ozone-tracer relation i...

Afshin Takdastan, Ali Akbar Azimi Ali Torabian Gholamreza Nabi Bidhendi Naser Mehrdadi

The excessive biological sludge production is one of the disadvantages of aerobic process such as SBR. So the problem of excess sludge production along with its treatment , and disposal in aerobic processes in municipal and industrial waste water can be seen in many parts of the world even in our country . to solve the problem of excess sludge production , reducing in by oxidizing some of t...

Background: Of the pharmacological modalities for knee osteoarthritis (OA), intra-articular injections including ozone(O3) and hyaluronic acid (HA) are commonly used for reducing pain and improving function. In this systematic reviewand meta-analysis, we aimed to compare the effect of O3 versus HA in reducing pain and increasing function in patientswith knee OA.Methods: ...

Journal: :Tree physiology 1997
C P Andersen R Wilson M Plocher W E Hogsett

Ozone exposure decreases belowground carbon allocation and root growth of plants; however, the extent to which these effects persist and the cumulative impact of ozone stress on plant growth are poorly understood. To evaluate the potential for plant compensation, we followed the progression of ozone effects, with particular emphasis on the development of new roots. Ponderosa pine (Pinus pondero...

1999
Susan Solomon

Stratospheric ozone depletion through catalytic chemistry involving man-made chlorofluorocarbons is an area of focus in the study of geophysics and one of the global environmental issues of the twentieth century. This review presents a brief history of the science of ozone depletion and describes a conceptual framework to explain the key processes involved, with a focus on chemistry. Observatio...

Journal: :Environmental science & technology 2001
M E Sather J L Varns J D Mulik G Glen L Smith C Stallings

Attaining the current lower tropospheric U.S. ozone standards continues to be a difficult task for many areas in the U.S. Concentrations of ozone above the standards negatively affects human health, agricultural crops, forests, and other ecosystem elements. This paper describes year two (1999) of a regional networking of passive and continuous ozone monitoring sites in the Dallas-Fort Worth (DF...

2005
V. Grewe

Highest atmospheric ozone production rates can be found at around 30 km in the tropical stratosphere, leading to ozone mixing ratios of about 10 ppmv. Those stratospheric air masses are then transported to extra-tropical latitudes via the Brewer-Dobson circulation. This is considered the main mechanism to generate midand high latitude ozone. By applying the climate-chemistry models E39/C and MA...

2000
EUGENE C. CORDERO TERRENCE R. NATHAN

The effects of wave and zonal mean ozone heating on the evolution of the quasi-biennial oscillation (QBO) are examined using a two-dimensional mechanistic model of the equatorial stratosphere. The model atmosphere is governed by coupled equations for the zonal mean and (linear) wave fields of ozone, temperature, and wind, and is driven by specifying the amplitudes of a Kelvin wave and a Rossby–...

Journal: :Environmental science & technology 2015
Ines Zucker Yaal Lester Dror Avisar Uwe Hübner Martin Jekel Yigal Weinberger Hadas Mamane

In this Article, we demonstrate the influence of effluent particles (in the range of <50 μm) on ozone degradation of trace organic contaminants (TrOCs) and effluent-quality parameters. Secondary effluent was filtered through different pore-size filters and ozonated at various ozone doses. Degradation of both ozone-reactive and ozone-refractory contaminants improved following ozonation of efflue...

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