A series of hydrocarbons containing both chlorine and fluorine. These have been used as refrigerants, blowing agents, cleaning fluids, solvents, and as fire extinguishing agents. They have been shown to cause stratospheric ozone depletion and have been banned for many uses.
A group of methane-based halogenated hydrocarbons containing one or more fluorine and chlorine atoms.
Compressed gases or vapors in a container which, upon release of pressure and expansion through a valve, carry another substance from the container. They are used for cosmetics, household cleaners, and so on. Examples are BUTANES; CARBON DIOXIDE; FLUOROCARBONS; NITROGEN; and PROPANE. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
A group of ethane-based halogenated hydrocarbons containing one or more fluorine and chlorine atoms.
The unstable triatomic form of oxygen, O3. It is a powerful oxidant that is produced for various chemical and industrial uses. Its production is also catalyzed in the ATMOSPHERE by ULTRAVIOLET RAY irradiation of oxygen or other ozone precursors such as VOLATILE ORGANIC COMPOUNDS and NITROGEN OXIDES. About 90% of the ozone in the atmosphere exists in the stratosphere (STRATOSPHERIC OZONE).
A shift in the balance between production and destruction of STRATOSPHERIC OZONE that results in a decline of the amount of OZONE in the lower stratosphere.
Ozone in the Earth's stratosphere. It is produced continuously by the action of solar ULTRAVIOLET RAYS on oxygen in the stratosphere. The stratospheric ozone (especially at the ozone layer) blocks much of the solar UV radiation of wavelengths of 320 nanometers or less from being transmitted to lower ATMOSPHERE of the Earth.
The reactions and interactions of atoms and molecules, the changes in their structure and composition, and associated energy changes.
A hydrocarbon used as an industrial solvent. It has been used as an aerosal propellent, as a refrigerant and as a local anesthetic. (From Martindale, The Extra Pharmacopoeia, 31st ed, p1403)
The maintenance of certain aspects of the environment within a defined space to facilitate the function of that space; aspects controlled include air temperature and motion, radiant heat level, moisture, and concentration of pollutants such as dust, microorganisms, and gases. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The mechanical process of cooling.
A series of hydrocarbons containing BROMINE; CHLORINE and FLOURINE.
The science of controlling or modifying those conditions, influences, or forces surrounding man which relate to promoting, establishing, and maintaining health.
An agency of the NATIONAL INSTITUTES OF HEALTH concerned with overall planning, promoting, and administering programs pertaining to advancement of medical and related sciences. Major activities of this institute include the collection, dissemination, and exchange of information important to the progress of medicine and health, research in medical informatics and support for medical library development.
A greenish-yellow, diatomic gas that is a member of the halogen family of elements. It has the atomic symbol Cl, atomic number 17, and atomic weight 70.906. It is a powerful irritant that can cause fatal pulmonary edema. Chlorine is used in manufacturing, as a reagent in synthetic chemistry, for water purification, and in the production of chlorinated lime, which is used in fabric bleaching.
Inorganic compounds that contain chlorine as an integral part of the molecule.
Atomic species differing in mass number but having the same atomic number. (Grant & Hackh's Chemical Dictionary, 5th ed)
A group of symptoms that are two- to three-fold more common in those who work in large, energy-efficient buildings, associated with an increased frequency of headaches, lethargy, and dry skin. Clinical manifestations include hypersensitivity pneumonitis (ALVEOLITIS, EXTRINSIC ALLERGIC); allergic rhinitis (RHINITIS, ALLERGIC, PERENNIAL); ASTHMA; infections, skin eruptions, and mucous membrane irritation syndromes. Current usage tends to be less restrictive with regard to the type of building and delineation of complaints. (From Segen, Dictionary of Modern Medicine, 1992)
Reproduction of data in a new location or other destination, leaving the source data unchanged, although the physical form of the result may differ from that of the source.
Organic compounds that have a relatively high VAPOR PRESSURE at room temperature.
Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)
Supplying a building or house, their rooms and corridors, with fresh air. The controlling of the environment thus may be in public or domestic sites and in medical or non-medical locales. (From Dorland, 28th ed)
The contamination of indoor air.
An institute of the CENTERS FOR DISEASE CONTROL AND PREVENTION which is responsible for assuring safe and healthful working conditions and for developing standards of safety and health. Research activities are carried out pertinent to these goals.
A nonmetallic, diatomic gas that is a trace element and member of the halogen family. It is used in dentistry as flouride (FLUORIDES) to prevent dental caries.
Statistical formulations or analyses which, when applied to data and found to fit the data, are then used to verify the assumptions and parameters used in the analysis. Examples of statistical models are the linear model, binomial model, polynomial model, two-parameter model, etc.
A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.
The study of chance processes or the relative frequency characterizing a chance process.
The condition in which reasonable knowledge regarding risks, benefits, or the future is not available.
The branch of mathematics dealing with the purely logical properties of probability. Its theorems underlie most statistical methods. (Last, A Dictionary of Epidemiology, 2d ed)
A theorem in probability theory named for Thomas Bayes (1702-1761). In epidemiology, it is used to obtain the probability of disease in a group of people with some characteristic on the basis of the overall rate of that disease and of the likelihood of that characteristic in healthy and diseased individuals. The most familiar application is in clinical decision analysis where it is used for estimating the probability of a particular diagnosis given the appearance of some symptoms or test result.
The complete summaries of the frequencies of the values or categories of a measurement made on a group of items, a population, or other collection of data. The distribution tells either how many or what proportion of the group was found to have each value (or each range of values) out of all the possible values that the quantitative measure can have.