Search results for "Ozone"

Stratospheric sulfur and its implications for radiative forcing simulated by the chemistry climate model EMAC

2015

Multiyear simulations with the atmospheric chemistry general circulation model EMAC with a microphysical modal aerosol module at high vertical resolution demonstrate that the sulfur gases COS and SO2, the latter from low-latitude and midlatitude volcanic eruptions, predominantly control the formation of stratospheric aerosol. Marine dimethyl sulfide (DMS) and other SO2 sources, including strong anthropogenic emissions in China, are found to play a minor role except in the lowermost stratosphere. Estimates of volcanic SO2 emissions are based on satellite observations using Total Ozone Mapping Spectrometer and Ozone Monitoring Instrument for total injected mass and Michelson Interferometer fo…

Improvement of the Valencia region ultraviolet index (UVI) forecasting system

2012

The CEAM Foundation (Valencia, Spain) has developed an operational ultraviolet index (UVI) forecasting system based on the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model. The main objective of this system is to provide the general public with a tool to minimize the impact of ultraviolet (UV) radiation, which can cause important human health problems. The system presented in this paper has been developed in collaboration with the Environment Department of the Regional Government of Valencia, and it replaces the one running until 2007. The new system substitutes the previously used Ozone Monitoring Instrument (OMI) observed data with the total ozone column data forecasted …

Measurements of total ozone amount over Badajoz (Southwestern Spain) by means of a GUV multiband radiometer

2012

This paper presents the first measurements of total ozone amount performed at the radiometric station of Badajoz (Spain) by means of a multichannel radiometer GUV-2511. The retrieval of total ozone amount from GUV measurements of solar ultraviolet irradiance is performed with the support of look-up tables calculated using the SBDART radiation transfer code. This methodology is based on the different absorption by ozone suffered by the radiation at two certain near wavelengths. In this case the pair 305, 340 nm was chosen because of its better performance than the pair 305, 320 nm. The look-up table contains the ratio between irradiances at the mentioned wavelengths calculated under differen…

Ozone gas insufflation and infiltration for conservative surgical treatment of osteonecrosis of the jaw: preliminary results at 3 months

2018

the aim of this study was to evaluate efficacy and safety of ozone insufflation/injection in conservative surgical approaches of oNJ in two cancer patients.

Ozone insufflation and l-prf application in an idiopathic and recurrent case of osteonecrosis of the maxilla

2019

Stratosphere-troposphere exchange in the vicinity of a tropopause fold

2016

Abstract. Transport of air masses from the stratosphere to the troposphere along tropopause folds can lead to peaked ozone concentrations at ground level and hereby influence the long-term trend of tropospheric ozone. To improve the understanding of responsible processes and preferred regions of exchange, transient and reversible exchange processes in the vicinity of a tropopause fold are analysed on the basis of a case study. The global and regional atmospheric chemistry model system MECO(n), which couples the limited-area atmospheric chemistry and climate model COSMO-CLM/MESSy to the global model ECHAM5/MESSy for Atmospheric Chemistry (EMAC) is applied. Using similar process parametrisati…

Global impact of monocyclic aromatics on tropospheric composition

2017

Abstract. Aromatic compounds are reactive species influencing ozone formation, OH concentrations and organic aerosol formation. An assessment of their impacts on the gas-phase composition at a global scale has been performed using a general circulation atmospheric-chemistry model. Globally, we found a small annual average net decrease (less than 3 %) in global OH, ozone, and NOx mixing ratios when aromatic compounds are included in the chemical mechanism. This inclusion of aromatics also results in CO mixing ratio increases, which cause a general decrease in OH concentrations. The largest changes are found in glyoxal and NO3, with increases in the atmospheric burden of 10 % and 6 %, respect…

A multivariate approach of changes in filamentous, nitrifying and protist communities and nitrogen removal efficiencies during ozone dosage in a full…

2019

[EN] The application of low ozone dosage to minimize the problems caused by filamentous foaming was evaluated in two bioreactors of an urban wastewater treatment plant. Filamentous and nitrifying bacteria, as well as protist and metazoa, were monitored throughout a one-year period by FISH and conventional microscopy to examine the effects of ozone application on these specific groups of microorganisms. Multivariate data analysis was used to determine if the ozone dosage was a key factor determining the low carbon and nitrogen removal efficiencies observed throughout the study period, as well as to evaluate its impact on the biological communities monitored. The results of this study suggest…

Elemental Bromine Production by TiO2 Photocatalysis and/or Ozonation

2016

Significant production of elemental bromine (Br2 ) was observed for the first time when treating bromide containing solutions at acidic pH, with TiO2 photocatalyst, ozone, or a combination thereof. Br2 selectivities up to approximately 85 % were obtained and the corresponding bromine mass balance values satisfied. The process is general and may be applied at a laboratory scale for green bromination reactions, or industrially as a cheap, safe, and environmentally sustainable alternative to the currently applied bromine production methods.

A Systematic Review of Air Quality Sensors, Guidelines, and Measurement Studies for Indoor Air Quality Management

2020

The existence of indoor air pollutants—such as ozone, carbon monoxide, carbon dioxide, sulfur dioxide, nitrogen dioxide, particulate matter, and total volatile organic compounds—is evidently a critical issue for human health. Over the past decade, various international agencies have continually refined and updated the quantitative air quality guidelines and standards in order to meet the requirements for indoor air quality management. This paper first provides a systematic review of the existing air quality guidelines and standards implemented by different agencies, which include the Ambient Air Quality Standards (NAAQS); the World Health Organization (WHO); the Occupational Safety and Heal…