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Chlorofluorocarbons ( CFCs) and hydrochlorofluorocarbons ( HCFCs) are fully or partly halogenated hydrocarbons that contain carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F), produced as volatile derivatives of methane, ethane, and propane . The most common example is dichlorodifluoromethane (R-12). R-12 is also commonly called Freon ...
Chlorine is cycled through the pedosphere via biotic and abiotic processes that lead to this reservoir acting as a sink. [1] [3] [4] [5] The chlorine cycle (Cl) is the biogeochemical cycling of chlorine through the atmosphere, hydrosphere, biosphere, and lithosphere. Chlorine is most commonly found as inorganic chloride ions, or a number of ...
The five most abundant greenhouse gases in Earth's atmosphere, listed in decreasing order of average global mole fraction, are: [ 5 ][ 6 ] water vapor, carbon dioxide, methane, nitrous oxide, ozone. Other greenhouse gases of concern include chlorofluorocarbons (CFCs and HCFCs ), hydrofluorocarbons (HFCs), perfluorocarbons, SF6, and NF3.
Retrospective video on the Montreal Protocol and the collaboration between policy-makers, scientists, and industry leaders to regulate CFCs. The Montreal Protocol on Substances That Deplete the Ozone Layer is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ...
Atmospheric carbon cycle. Schematic representation of the overall perturbation of the global carbon cycle caused by anthropogenic activities, averaged from 2010 to 2019. [ 1 ] The atmospheric carbon cycle accounts for the exchange of gaseous carbon compounds, primarily carbon dioxide (CO 2 ), between Earth's atmosphere, the oceans, and the ...
A third major source is marine algae, which produce several chlorinated methane and ethane containing compounds. Several thousand complex halocarbons are known to be produced mainly by marine species. Although chlorine compounds are the majority of the discovered compounds, bromides, iodides and fluorides have also been found in nature.
Fluorocarbons are colorless and have high density, up to over twice that of water. They are not miscible with most organic solvents (e.g., ethanol, acetone, ethyl acetate, and chloroform), but are miscible with some hydrocarbons (e.g., hexane in some cases). They have very low solubility in water, and water has a very low solubility in them (on ...
As of 2021, measured atmospheric concentrations of carbon dioxide were almost 50% higher than pre-industrial levels. [32] [33] The main sources of greenhouse gases due to human activity (also called carbon sources) are: Burning fossil fuels: Burning oil, coal and gas is estimated to have emitted 37.4 billion tonnes of CO2eq in 2023. [34]