نتایج جستجو برای: photochemical smog

تعداد نتایج: 11421  

Journal: :Mathematical Modelling in Civil Engineering 2013

2004
Linda J. Broadbelt

Objective: Emission of volatile organic compounds (VOC’s) into the atmosphere leads to increases in the concentration of ambient ozone, a major component of photochemical smog. Therefore, the ability to determine the contribution of a selected VOC to ozone formation would be extremely valuable for both environmental and industrial reasons. To this end, a promising strategy is to create detailed...

2000
A. Richter J. P. Burrows

Nitrogen oxides play an important role in the chemistry of earth’s atmosphere. In the troposphere, they provide the only chemical source for ozone, arguably the most important radical in the lower atmosphere. Nitrogen oxides are central in the formation of photochemical smog in the industrialised countries and also in regions with intense biomass burning. In addition to its relevance to troposp...

2017
Thomas Gautier Zhe Peng A. Giuliani Nathalie Carrasco Guy Cernogora Ahmed Mahjoub Jean-Jacques Correia Cyril Szopa P. Pernot A. Buch T. Gautier Z. Peng N. Carrasco G. Cernogora A. Mahjoub J.-J. Correia C. Szopa

We report here on the coupling of a gas reactor with a VUV beamline at the SOLEIL synchrotron radiation facility. The reactor may be irradiated window-less with gas pressure up to the atmosphere. The photochemistry is monitored by a mass spectrometer gas analyzer. This set up, termed APSIS for Atmospheric Photochemistry SImulated by Synchrotron, has been used to simulate the atmosphere of Titan...

2001
István Lagzi Alison S. Tomlin Tamás Turányi László Haszpra Róbert Mészáros Martin Berzins

An important tool in the management of photochemical smog episodes is a computational model which can be used to test the effect of possible emission control strategies. High spatial resolution of such a model is important to reduce the impact of numerical errors on predictions and to allow better comparison of the model with experimental data during validation. This paper therefore presents th...

Journal: :International journal of pharmaceutical and bio-medical science 2023

Smog is a harmful mixture of fog, smoke, dust and air pollutants such as nitrogen oxides, volatile organic compounds etc. Ground ozone can cause distressing health effect. complex atmospheric pollutant consisting ozone, with adverse effects on human health, vegetation, materials; other eye-irritant phytotoxic (such aldehydes peroxyacetyl nitrates); dioxide (cause the “whiskey-brown” color in Lo...

2000
S. Kondragunta R. R. Dickerson G. Stenchikov W. F. Ryan

High concentrations of both ozone and aerosols are observed in the eastern United States during stagnant weather conditions associated with transport from the W or NW; they show similar spatial and temporal patterns. We discuss a causal mechanism that may contribute to this correlation-the radiative eeects of aerosols on photolysis rates. We measured j(NO 2), the rate coeecient for nitrogen dio...

2012
G. J. Engelhart C. J. Hennigan M. A. Miracolo A. L. Robinson S. N. Pandis

We quantify the hygroscopic properties of particles freshly emitted from biomass burning and after several hours of photochemical aging in a smog chamber. Values of the hygroscopicity parameter, κ , were calculated from cloud condensation nuclei (CCN) measurements of emissions from combustion of 12 biomass fuels commonly burned in North American wildfires. Prior to photochemical aging, the κ of...

Journal: :BMJ 1991
F Godlee

relation to their workload."' Doctors in general practice may be salaried, paid on a capitation basis, or paid per item of service or per patient treated-or they may be paid by a combination of these methods. In the Netherlands, for example, the health insurance schemes fix an earnings target for general practitioners and calculate the capitation payment to provide 70% of this target. The assum...

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